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Ian Mackenzie
07-27-2008, 01:43 AM
Following recent prolific musings over E2 inspired ideas in the E2 clone thread I have elected to open a new thread on my own project.

I welcome on lookers and feedback but please refrain from splashing Monet's palette or Rolf Harris's 6 inch brush with subject matter that is just not relevant. It just makes it hard for those with a genuine interest to follow the real proceedings.

(Dont expect posts here every day or hundreds of SPL graphs. Do expect and system that sounds good and measures well. Sound Easy and various other tools will assist with optomising the system. In my experience most real problems are audible and the tools just help pin down where they are)

The notion behind my project is from the opening pages of the Everest and K2 product brochures. The idea being to bring to the table a 2 way based system that will deliver a very smooth, coherent and detailed sound not found in the earlier 43XX systems with hi sensitivity, low power compression and very low distortion. Will it be an MTM ? No. Will this be a rediculously expensive project. No. But dont expect it to be wife friendly.

Using a 2435 Be driver with acqualas treatment is preferred over titanium based/aquaplas treated drivers because of the superior resolution that beryllium brings to compression drivers. Careful selection of the woofer will it is hoped ensure that a higher crossover point deemed acceptable for the 2435 Be does not compromise performance.

My logic here is that superior accuracy can be obtained over titamium based compression drivers with good quality direct radiator 2 and 3 way systems so much so that a compromise in overall sensitivity is acceptable. But Beryllium in a properly execute horn/wave guide can offer resolution and sensitivity not found any other way.

It is not envisaged that a multiway horn system using 4 inch large format drivers will be explored.

The high frequency horn will be sourced from elsewhere because to the best of my knowledge the better quality JBL consumer horns are unobtainable now. It is intended that several types of full size horns will be trialed in the course of developing the project to explore and compare how they effect the sound.

Some links here to various horn offerings
http://www.artec-france.com/etudes.php?system=compact&item=pavillon&lang=en (http://www.artec-france.com/etudes.php?system=compact&item=pavillon&lang=en)
http://audioheritage.org/vbulletin/showthread.php?p=123500/lpost123500 (http://audioheritage.org/vbulletin/showthread.php?p=123500/lpost123500)
http://www.users.uswest.net/~ddshorns/cfd2-90x.htm (http://www.users.uswest.net/~ddshorns/cfd2-90x.htm)
http://www.users.uswest.net/~ddshorns/cfd2-110.htm (http://www.users.uswest.net/~ddshorns/cfd2-110.htm)
http://www.azurahorn.com/azurahorn_links.html (http://www.azurahorn.com/azurahorn_links.html)

Links to various woofers:



http://www.akoustik.fr/tad.php?RubID=5&r=Woofer
http://www.audioheritage.org/vbulletin/showthread.php?t=21713 (http://www.audioheritage.org/vbulletin/showthread.php?t=21713)
http://www.precision-devices.com/showdetails.asp?id=79 (http://www.precision-devices.com/showdetails.asp?id=79)
http://www.phlaudio.com/datasheets/38_pdf/5010.pdf (http://www.phlaudio.com/datasheets/38_pdf/5010.pdf)


In the earlier E2 clone thread I hinted at a idea of a JBL Suma (after Geddes).

While I admire much of Earls' work I think a lot of common sense applies to controlling the effect of the room by adequately treating early and near field reflections with appropriate room treatments. It is quite easy for example control stereo image width and depth with some basic room treatments just like they do in major recording studios. Even so horn with constant power response and those with flat only on axis response will be explored.

The notion of controlled and constant directivity will form a key aspect of the project where ideal and less then ideal power response will be examined and subjectively evaluated.. The effect and audibility of early and near field reflections will also be documented..

As far as selecting horns is concerned the intent here being that the system will where possible offer a controlled polar response and low horn related distortions.

From my own perspective this is as much about using a horn of the correct physical proportions rather than compromise performance for marketing or size considerations. I am not stacking horns for an array so there no point getting too excited about the cheapest, smallest horn to squeeze into the front baffle.

A fundermental study of horn theory and this is abundantly obvious. Even Earl agrees a 12 inch (1 khertz crossover point) waveguide is better then a 10 inch and a 15 inch works best.

Why use a pissy/sissy little ear lobe guide with a response like a wee dogs broken hind leg is beyond me . They are perfectly acceptable for SR applications but less than ideal for high quality audio playback where mininal reflections and diffraction distortions are preferred.

There are pretty horns out there too like the Tad 1400 clones seen on Ebay.

The thread has been place here to allow flexibility in using other than purely JBL drivers and parts to fine tune and optimise the system by selecting customised hand built woofers if required. In the case of the 1500AL it would be ideal but the cost and shipping are I imagine outside the scope of this project. Of course if I am convinced that a particular JBL woofer meets the requirements then it will be used. I have not determined what size woofer or how many per channel yet or what type of tuning .

I dedicate this thread to our good friend Rich who it would seem is MIA by all accounts. I doubt if my woodwork will ever be up to Rich's standards but there will be little to moan about otherwise...LOL:D

For those interested I will be selling off some 4345 related drivers at some stage....all going well.

These link's represent the type of system I am considering. Nothing too outlandish but quality. As they say the devil is in the details but as you can see in all these images the horn is not small.....nor the woofer.

http://www.audioheritage.org/vbulletin/showthread.php?t=20088

http://www.audioheritage.org/vbulletin/showpost.php?p=204405&postcount=52
http://www.audioheritage.org/vbulletin/showpost.php?p=204405&postcount=52
http://www.audioheritage.org/vbulletin/showpost.php?p=204405&postcount=52
http://www.audioheritage.org/vbulletin/showpost.php?p=204405&postcount=52
http://www.audioheritage.org/vbulletin/showpost.php?p=204405&postcount=52



Ian

Ian Mackenzie
07-27-2008, 06:01 PM
Like any project there needs to be resources and at this point that primarily points to information and know how in terms of attempting to make your own horns.

Thanks to Bruno Ginard in Lyon France for emailing details of some horn plans. I have fond memories of red wine tasting in Lyon!

Here is an excellent web page on making your own hi end wood horns.

http://www.geocities.jp/arai401204/index.html

http://www.geocities.jp/arai401204/Horn/A290S/A290-S90.html

I should have details of the woofer (with Tad specification soon) and a CNC monitor horn is in the pipeline but that will be some time off.

Ian

richluvsound
07-28-2008, 11:04 AM
I ain't missing :D

just keeping busy with other passions.

love to all, Rich

Chas
07-28-2008, 11:13 AM
I ain't missing :D

just keeping busy with other passions.

love to all, Rich

Hey, you're still alive! Now we need Zilch to interpret those curves you posted.:D

Skywave-Rider
07-28-2008, 02:16 PM
Hey, you're still alive! Now we need Zilch to interpret those curves you plotted.:D

Yes.
Gotta love the team.


Alas, I am only a spectator....

Ian Mackenzie
07-28-2008, 03:01 PM
Ah there you are!.

Nice to see you Rich.

If you have French as a second language it may prove useful. They appear to quite engaged in audio.

As far as the horn making goes I have not make any firm decision..just gathering ideas and some designsat this point.

Ian

Ian Mackenzie
07-28-2008, 03:02 PM
I will post a simulation of the woofer sometime this week.



Ian

richluvsound
07-28-2008, 05:57 PM
Hi Ian,

I have been thinking seriously about a new speaker. I would like to move to somewhere smaller, the 45's are the only real issue. It will be great to see what you come up with.

a mate !

PS nothing French in my life anymore-only memories

Ian Mackenzie
07-28-2008, 06:56 PM
Okay,

You should come to Australia and live in a beach house and paint visions of skimpy bikini's.

I don't think this system will be too large, the horn will not be tiny though.

Ian

Ian Mackenzie
07-29-2008, 01:39 AM
Hi Ian,

I have been thinking seriously about a new speaker. I would like to move to somewhere smaller, the 45's are the only real issue. It will be great to see what you come up with.

a mate !

PS nothing French in my life anymore-only memories

Rich,

I would suggest there is none better than this offering by Jean-pierre:

http://www.artec-france.com/etudes.php?lang=en&system=compact&PHPSESSID=c737576dee1bd6547a11b8dca00cc48e

http://www.artec-france.com/etudes.php?lang=en&system=compact&item=mediumgrave

I have reviewed this designed and shared emails.

Outstanding.

If you still have the Tad 2002 then you can realise this design.

The horn Jean-pierre has designed is very very good.

http://www.artec-france.com/etudes.php?lang=en&system=compact&item=filtre


For those of you want to also down scale with a JBL woofer could use the JBL 1200fe if you have a Tad 2001 or 2002 but you will need to do a complete crossover design and access to test equipment. (I would describe the level of difficulty in doing that as high and should only be attempted if you have the time, skills and relevant test equipment)

Ian

readswift
07-29-2008, 02:56 AM
hey, I tought about mounting a 12" Geddes front baffle (& seal the woofer cut out) on the upper half of a 4435, it'd look cool too.

Ian Mackenzie
07-29-2008, 04:26 AM
Well I hope it does not get to noisy now the thread has been moved.

As I said earlier I am not necessarily proposing to use stock JBL components or titanium based large format drivers. The reasons have been outlined earlier.

Those when want to go that route should consider the Tad 4001 as your best affordable option. I may even look at the Tad if the opportunity arises. (some good deals SH on the Tad 4001, or the JBL 2441 aluminium based diaphragm that has been tested for perform well with some of the diy wood horns). Dont get me wrong, the 2452 series are nice drivers but even the acquaplas treated diaphragms are not in the hunt according to reports from Studio's hence they invariably use the Tad drivers.

Of interest here is a link to the engineer of the Australian woofer that has drawn my attention. My understanding this they have a plant for making paper based cones with in house CNC tooling.

I came across Lorantz when doing broad search for suitable woofers. Michail Brarabasz the MD of Lortanz responded to an email for information and advised he can spec make a woofer to Tad or better of his own design as a result of demand from the local market and is planning to provide a suitable CNC wood horn. It will be interesting to see what Michail comes up with. Michail has written an AES paper on diaphragms and is acknowledged as an expert in magnetic circuit design and voice coil engineering.

I propose to visit the plant in the next few weeks.

Lorantz Audio Services was born in 1975, starting with many speaker components and speaker tooling purchased from the closure of Plessey Rola Co. Lorantz Audio Services commenced producing 6â€, 8†10†and 12†loudspeaker. Read more. The product range diversified to meet customer requirements, and the business was incorporated in 1990. In 1995 Hazel and Michail Barabasz of Lorantz were awarded the "Service to the Industry Award" by the Melbourne division of Audio Engineering Society for the development and manufacture of loudspeaker technology of the highest quality for a period of over 30 years.
Hazel and Michail Barabasz recipients of the AES Services to Audio Industry award 1995.

In 1995 Lorantz introduced CNC machining to achieve consistent high quality control standards in manufacturing


http://www.lorantz.com.au/about.php

http://www.lorantz.com.au/process.php#loudspeaker_system_designs

http://www.lorantz.com.au/process.php

richluvsound
07-29-2008, 11:12 AM
Ian,


I could use a sub with the DEQX as a 3-way x-over or an augmented twin 1200fe type set up. Any idea how high the 1200 can run with 2002?

Rich

Ian Mackenzie
07-29-2008, 03:14 PM
Ian,


I could use a sub with the DEQX as a 3-way x-over or an augmented twin 1200fe type set up. Any idea how high the 1200 can run with 2002?

Rich

Rich,

You wont need a sub with the 1200fe and I think that really gets away from the notion of a compact system. If you want disco levels then like forget it. This driver is at best 91-92 db sensitivity and its a 12 not an 18 inch woofer.

Just stack them vertically if you feel so inclined but that is starting to look like a big box. So I would suggest one driver to start with or look for a 15 inch driver which is my preference.

On the 1200fe crossover point you will need to explore this yourself and look at what JBL does with that driver in systems like the 4428 and the 5800. Start with an 18 db network on the woofer @800 hertz. The spec sheet on the 1200fe is self explanatory if you understand what sort of driver the 1200fe is.

I have not heard the 1200fe set up with the Tad 2002 so I cannot make any recommendations.

Its more a case of the horn you decide for the 2002 but again I would not push it below 800 hertz.

The Tad 1102 is another really excellent driver and would be my pick .
http://www.pioneer.co.uk/uk/products/43/203/1083/TL-1102/index.html

If I had the Tad 2002 (:banghead:) I would use the AR2140H horn with the Tad 1102.

Image courtesy of Jean-Pierre Landragin

The usual caveats apply. None of this is ever going to be plug and play.

Also please respect that these diy offerings by Jean-Pierre are never to be produced for commerical profit.

Ian

Ian Mackenzie
07-30-2008, 08:57 PM
Recources:

Some people have suggested digital crossovers for flexibility.

At some point I will look at extending SoundEasy capabilities for live digital crossover simulation using a high end 2 in 3 out PCI card as part of this project.

This may prove valuable if some of the earlier and deeper style Tad horn designs are utilized where some for of time delay is required.The larger and deeper Tad horns specify a 4 inch driver. The Tad 4001/ 4001 appears the logical choice as a suitable driver.

Another woofer that has emerged as a likely candidate is the AE 15M. The AE 15m allows running the driver up to 1.5 khertz acording to the designer will little loss in off axis response.

I will post details of this driver in due course.

I propose to arrange a visit to Lorantz in the next few weeks to look at their CNC wood horn developments.

As can be appreciated there is stready progress and it is hoped the result will be something that actually sounds like real music and not just a loud noise. The intention being a bit more discerning over the choice of components and how they are used.

Ian

Ian Mackenzie
08-02-2008, 02:05 AM
Along with other resources we need an loudspeaker crossover tool box.

To correctly design a loudspeaker crossover network requires collection of data/ measurement and a means of designing and optimising the crossover functions.

This can be done in the analogue domain with passive filters or analogue active filters.

There is also emerging technology to use the digital domain as shown in this link:

http://www.acourate.com/#TUTORIALS (http://www.acourate.com/#TUTORIALS)

Prior to starting this phase of the system development it is important to have some system goals.

Once the goals have been determined and proven realistic and viable the specifications that will meet the requirements can be set as targets.

Individual components can then be selected on the basis of meeting the target specifications.

The significance of this approach is that you can specify the system around your goals rather then attemping to specify the end goals against particular components. I have seldom seen projects work out well on that basis. For diy purposes the latter might be a more pragmatic approach but it is important to have a clear understanding of what your componments will and won't do.

For example in the case of most if not all the JBL PT wave-guides they were never intended to be used below 2,000 hertz (the CM cone based wave-guides work from 200- 2000 hertz) in the JBL systems and yet we see people trying to make them go below 900 hertz.

http://www.jblpro.com/PD5000/PDF/JBL_PD5322_95_CutSheet.pdf (http://www.jblpro.com/PD5000/PDF/JBL_PD5322_95_CutSheet.pdf)

In this example the PT-H95HF is passively crossed over at 36 db per actave @1.5 khertz using the 2431 compression driver.

Very often JBL components are designed and specified for a particular system or application..just like any other manufacturer. If you are cloning a system and have all the components on hand then your job is mostly done.ie a JBL 4343 or 4435.

But if you are starting from almost a clean sheet of paper with perhaps one dependant or known component ie the 2435 compression driver then there is a lot more to consider. For the diy project cost and availability will impact on the above process but there is no harm is carefully assessing all the viable options.

Broadly stated my goal is:

"The idea being to bring to the table a 2 way based system that will deliver a very smooth, coherent and detailed sound not found in the earlier 43XX systems with hi sensitivity, low power compression and very low distortion. Will it be an MTM ? No. Will this be a rediculously expensive project. No.''

Breaking down that goal into specifics ; smooth response, coherent, detailed sound, hi sensitivity, low power compression, low distortion.

Without going into micro detail at this point I need to specify my sensitivity target,: What is a hi sensitivity system? 90db 1 watt, 93 db 1 watt 96 db 1 watt , 99 db 1 watt.

Why do I want a high sensitivity system?

So I can use less powerful amps of very high quality. All things being equal high sensitivity systems have lower power compression and lower distortion and higher dynamic range than the low or moderate sensitivity counterparts. This is / was clearly audible in A/ B comparisons when I visited John Nebel's wall of sound in 2004 and we compared the 4435 to the LRS6332. The LRS system was more accurate in some repects but the 4435 was more life like in its presentation imho. Its was very obvious the LRS system needed far more power for the same levels.

I think 90 db is average for a home audio loudspeaker and 99 db is very high in the PA category. A more meaningful measure is the amount of power required for a specificed acoustic output at 1 metre. A 96 db sensitivity system is only going to need 1/4 of the power of the 90 db system for the same acoutic output.

So if a 90 db system needed a 100 watt amp to produce the require dynamic range then the 96 db system would need a 25 watt amp. When you are operating full biased class A amps these are serious considerations in terms of power consumption and okay global warming!

I do have on hand a 500 watt class A, A/B amp and I propose to use this for the woofer and a smaller fully biased class A amp for the compression driver.

But seriously I tend to believe along with many other people that a properly designed systems of hi sensitivity have better retrieval of micro dynamic and spatial detail.

So I can live with somewhere in the range of 95-96 db 1 watt.

Now the other goals: smooth response, coherent, detailed sound

Fortunately a 2 way design supports the requirement for a coherent sound because there is only 1 crossover point in the most audibly sensitive part of the human hearing frequency range. Just exactly where the crossover point will be and the type of filts is yet to be determined but it will be somewhere between 800-1.5 kertz.

I think +- 3 db for the woofer and +- 2 db for the horn is a reasonable and realistic specification. Smoothness in the 1-4 khertz range is most important. I have not set frequency bandwidth yet. This will be somewhat influenced by my room, particularly room gain. However on paper I would like - 6db points of 45 hertz and 20 khertz

Below and above these points may require some augmentation from an ELF device/ aka helper woofer or a super high frequency transducer. This will be determined by the in-room response and subjective performance.

In terms of the how part and what components to specify I have drawn up a spread sheet of all the likely candidates in terms of woofers and horns.

Obviously a 90 db sensitivity woofer is not going to work within my specifications.

But if I parralleled two woofers the net sensitivity would be 95-96 db @ 4 ohms.

Lower/modest sensitivity woofers tend to have extended bass response but they are not always to well suited to reproducing the midrange region and can have a peak as a result of break-up of the somewhay heavy and stiff cones that are best suited for extended bass woofers.

This would limit crossover point options. So it will be a case by case selection if that scenario presents itself. The JBL 1200 Fe http://www.audioheritage.org/vbulletin/showthread.php?t=21713 (http://www.audioheritage.org/vbulletin/showthread.php?t=21713)

and the Visation TIW 300 http://www.soundlabsgroup.com.au/bildgross/840_afrequenzgang.html (http://www.soundlabsgroup.com.au/bildgross/840_afrequenzgang.html)
are options in that category.

As to single drivers of 95-96 db there are too many to discuss here but the options included a driver in prototype stage made by a local firm Loranz who claim Tad performance, the Tad 1600 series drivers if they are available, the JBL 2234 and a interesting mid bass woofer by Precision Devices PDN.15BR40 Neodymium http://www.precision-devices.com/showdetails.asp?id=79 (http://www.precision-devices.com/showdetails.asp?id=79) .Audio Elegance also have some interesting 15 inch woofers using a novel motor to reduce flux modulation.

A woofer that provides easier crossover integration like the Precison Devices PDN 15BR40 and the Loranz AC-390X-B1 will have preference.

I have ruled out the JBL 1500AL on grounds of the hazards of shipping such a heavy driver and cost. ( I estimate it would cost $500 to ship each driver)

At this point the 2435 be compression driver is a given but it maybe upgraded to a large format 4 inch driver pending how the project turns out.

The type of horn or wave-guide will be critical and I propose to try at least two alternatives. I am looking a several wood horns, one of which will be CNC machined and fibreglass offerings from Azzrahorn and DDS.

When I have more specifc data and applications recommendations on some of the drivers I will post details.

Ian Mackenzie
08-04-2008, 04:07 AM
A couple of concept images if what the end result may look like:

Robh3606
08-04-2008, 05:03 AM
Hello Ian

You might want to see how the 2435 plays out on your chosen horn. They can run out of room up top. Depending on how well the top end on the horn plays it may limit your woofer sensitivity on a passive set-up. Best bet may be active depending on what drivers you end up choosing.

Rob:)

Hoerninger
08-04-2008, 05:36 AM
The oval "concept" horn looks interesting.

In the horizontal plane the flanges are opening wide just as the tractrix horn or the Kugelwellentrichter do. It can even be compared with the EII horn - without sharp angles - measurements concerning the divergence would be interesting.
__________
Peter

Ian Mackenzie
08-04-2008, 05:59 AM
Hello Ian

You might want to see how the 2435 plays out on your chosen horn. They can run out of room up top. Depending on how well the top end on the horn plays it may limit your woofer sensitivity on a passive set-up. Best bet may be active depending on what drivers you end up choosing.

Rob:)

Hi Rob,

Good point.

I agree it will depend on the horn and I think this is on the data sheet as I recall.

Going active is on the agenda so as not to fall foul of the problems Eq and level shifting issues experienced with another project.

I do not see what the big deal is about making it go flat to 20 Khertz, my spec is -6 @ 20 K herta as was in Gregs's diy system. I can't hear much reliably past 13 Khertz..its all air and ambience.

The plan a few horns even if have to borrow some and use a 1.5 to 2 inch adapter (which might actually work better) just to get a feel for what it does.

If it proves too big a PITA I will Ebay it or bin it and buy a Tad 4002/4001 which frankly I should have done at the outset and run a ribbon above 10 khertz.


ian

Ian Mackenzie
08-04-2008, 06:16 AM
The oval "concept" horn looks interesting.

In the horizontal plane the flanges are opening wide just as the tractrix horn or the Kugelwellentrichter do. It can even be compared with the EII horn - without sharp angles - measurements concerning the divergence would be interesting.
__________
Peter

It sure looks nice

I think its is a hyprid much like so many horns today with a hyperbolic/ exponential throat and then secondary planes that are seemless.

The earlier EV CE horns by Keele pioneered this approach according to an AES paper I down loaded recently. The Peavy Quadratic wave-guide is another hyprid (I plan to buy a pair).

Below is a very good paper on the evolution of constant directivity horns.

The smooth eliptical shape hides the contours.

The elipical shape overcomes the issues of the Geddes wave guide on axis as I understand it. In a way I imagine this is the next step on from the Geddes.

I have requested data.

I think they use a customised BMS concentic driver.

Also from www.stereo-lab.de (http://www.stereo-lab.de) on offer is a new pair of wonderful 1.5“ CF > 400 Hz Tractrix Horns made by Stereo-Lab.de. Diameter ~ 310 mm, Length ~ 290 mm, Thickness ~ 10 mm, made of a composite material which is poor in resonance, milled flange, inside and outside perfect finish with black structural studio coat.

Ian Mackenzie
08-04-2008, 03:06 PM
Those eliptical horns are not available for sold sale seperately.

Ian

Jakob
08-07-2008, 06:09 AM
Hi Ian!

When it comes to the 15"-drivers, have you considered the ME150? I know they could be bought at a very reasonable price from JBL earlier and it's a very impressive driver.

Regarding stereolabs tractrixhorn I saw on one of your pictures, I own a pair of 400hz flares that I use daily with some 2450's. They sound very good, but when comparing to the H9800 they image bad, at least in my setup (room etc).

Good luck on your quest!

Ian Mackenzie
08-07-2008, 06:21 AM
Previously unidentified issues seem to be creeping in on finding or should I say obtaing the desired drivers.

The Australian operation is not being very co operative or should I say not user friendly since they learn I am a JBL feak by referring them to the forums, they hate JBL with a vengence and want to charge me for measuring the drivers.

I have two options for the low end , maybe three at this stage.

Twin Visation 12 inch TIW300 woofers mentioned earlier.

Tad 1601/1603

A hyprid woofer configuration of the JBL 2245 below 50 hertz and a mid bass driver , either a 2234, a Pecsision Devices PDN.15BR40 Neodymium or Tad 1601.

The former is a pre engineered arrnagement in 180 litres only -4 db down 30 hertz ansd -6 db down at 25 hertz with slight rolloff below 100 hertz to account for room gain and wall boundary (fb 24.6) . Mid band senitivity ref 2.83 volts 97 db . Other tuning options are available.

The Tad option is nice.

The 1601 in an optimum tuned box is -6 db at 36 hertz in 97 litre box , the 1603 is -6 db at 31 hertz with only 132 litre box. The 1601 is somewhat more sensitive at 97 db compared to about 95 db for the 1603 from what I have seen.

The final option is a an idea of using the 2245 below 50 hertz and a studio Mid bass driver from Precision Devices (Neo) http://www.precision-devices.com/showdetails.asp?id=79 with all the bells and whistles.

There are some benefit despite the complexity. Crossover to the horn is more flexible up to nearly 2000 hertz,independent (IET) of both the 2245H and the mid bass so I can have extended bass and a punchy upper bass..

The Precision Devices driver is somewhat similar to the Tad 1601 curve and box size but the Tad is a little more extended. The 1691 can be crossed over up to 1200 hertz

Assuming I can obtain the Tad 1601 or the 1603 I will most certain acquire a pair.

The thing I like about all these 15 inch drivers is they are weighted towards high sensitivity for good mid bass performance and they are very clean. The 2245 can of course to used for ELF or as a help woofer wit any of these setups.

Non of the above comparisons take into account room effects.

This is another benefit of the small boxes using the tads drivers, they can be got off the floor with the horn at a comfortable listening height.

Odd as it may seem after looking at what I think will work the best for my two way system I come around to the Tad drivers. This does not mean to say none of the JBL drivers would work, they would but I think at this point the Tad drivers if available ( checked delivery 8-12 weeks) have the edge.

Ian

Ian Mackenzie
08-07-2008, 06:23 AM
Hi Ian!

When it comes to the 15"-drivers, have you considered the ME150? I know they could be bought at a very reasonable price from JBL earlier and it's a very impressive driver.

Regarding stereolabs tractrixhorn I saw on one of your pictures, I own a pair of 400hz flares that I use daily with some 2450's. They sound very good, but when comparing to the H9800 they image bad, at least in my setup (room etc).

Good luck on your quest!

I had not thought about the ME150..not much information on it it would seem.

Thanks for the tip on the horn

Please appreciate my original plan was to make a system like Greg's diy home system but as we know the horns are no more which is really unfortunate. So I have come up with something else that I hope has a high probability of being better than what I already have. I am confident a Tad based system will realise that goal. I also have a lot of information available on diy tad horns and access to an soa active crossover either analogue or digital .



Ian

stephane RAME
08-07-2008, 08:36 AM
A couple of concept images if what the end result may look like:

http://www.haigner.com/
http://www.theaudioeagle.com/david_designs.html
http://www.theaudioeagle.com/columns/column04.html
http://www.theaudioeagle.com/joe_designs.html

Ian Mackenzie
08-07-2008, 03:15 PM
They are interesting.

I propose to get away from the chunky box look if I can, probably a polygon.

The graph below is is only a guide. But it indicates a rising response at low frequencies. As speakers descend in frequency they become increasingly omni-directional. This means they become, gradually, a spherical radiator. The increased energy then bounces back into the room.

Courtesy of Martin Colloms and his book High Performance Loudspeakers:

The Colloms Curve & Average Room

Next I will try and superimpose this on the standard 2Pi response.

As a rule and if carefully taken into account, the tuning to allow for room gain assists in placement of the loudspeaker in the listening space.


In a recording studio the scenario particularly different where sofit mounting of large monitors is employed.

Below is the normalised family of curves incorporating the above Colloms Average Room.

This is interesting because so many of us use simulations but how often do weconsider the effect of room infulence in your tuning?

One of those drivers is a 2235 red in 5 cu ft 3 tuned to 28 hertz, the maxium of the hump is 2.9 db at 60 hertz.

In the overal scheme of things you might accept that as a flat bass response and be used to it over time but not to a trained ear.

The other curves are the tad 1601 blue/1603 yellow and the Precision Devices mid bass woofer green.

But what I find equally interesting is that the ear is most sensitive to the level of bass in the 35-50 hertz region. This is well documented by Witold Waldron (creator of Calsod) and other scientists.

The last family of curves is the tad 1601 Yellow and the 1603. In each case we have an optimum tuned box and a customised large box (about 50%) tuned to 25 hertz.

This is known as a dynamic alignment where the box is tuned to the best optimally flat response in the room. Of course it would need to be tested and voiced and a high pass filter used to avoid excessive excursions.

But as you can see the response is far flatter and there is significantly more low end extension.

Wit the dynamic alignent the Tad 1601 has a maximum hump at 63 hertz of 1.3 db and is -3 db down at 25 hertz and -6 db at 21 hertz. In the optimium 2Pi box alignment the 1601 is -3db at 31 hertz and -6 db at 27 hertz.

The Tad 1603 is -3 db at 22 hertz with the dynamic alignment.


In attempting this type of tuning you woud need to weigh up if the loss in dispacement limited output was worth while. Usually there is a compromise were there will be some benefit of extended output and smoother in room response.

There is another way of providing modifed room response. Electrical Equalization.

This can be analogue or digital

Ian Mackenzie
08-09-2008, 02:57 PM
Here is a B6 class 1 response of the Tad1601b (without room gain)

The actual maximum output on that curve is not correct so I have posted a BassBox simulation of the output and unassisted response.

Ian

Joe Alesi
08-09-2008, 05:19 PM
The Australian operation is not being very co operative or should I say not user friendly

Bloody Australians:D:D:D



.....since they learn I am a JBL feak by referring them to the forums, they hate JBL with a vengence and want to charge me for measuring the drivers.

Hello Ian,

If you need any help measuring the drivers freq. response I can help, once I sort out my dying laptop sound card. If you need Thiele/Small Parameters this is also possible but VERY handraulic.

Best
JA

Ian Mackenzie
08-09-2008, 06:54 PM
Hi Joe,

Thanks for the offer. I am a fair way off any measurements at this point but but will keep it in mind.

About the local well I guess he is of a factory mind-set. I think it must be the genes. The Poms are worse though.

When I asked for details of his claim they were as good as Tad/JBL like some LMS distortion measurements and other data I got a pelted with stones and every excuse you could think of not to provide data. The only supporting statements were his drivers are un breakable and better made.

In any case unless he come sup with something remarkable I dont be wasting further time in that direction.

Ian Mackenzie
08-09-2008, 07:35 PM
I have not decided if I will use two woofers per box yet like the JBL 4435 or a vertical array like the 1200fe box 4313B posted.

I need to do some room response models and some measurements to try and assess the true room gain below 100 hertz for this system.

At the end of the day if I need to provide for example - 3 db of downward equalisation contour below 100 hertz due to room gain for a relatively smooth bass curve (with the box near the rear wall) this will mean a reduction in cone excursion limts and distortion.

By way of example I recall hearing Bo's 4345 that had been setup nicely and the bass for not exagerated but was smooth and articulate.

Obviously the E2 with dual woofers was an all out effort for massive dynamic range but common sense prevails in terms of the room size and what will give the best overall results.

Ian Mackenzie
08-10-2008, 03:02 PM
Horn crafting.

I always wonfered how to create the horn flare and machine i wood.

Here is one way used by a professional in HK

Not as simple as it looks and the process is long to final assembly.

Lots of noise and saw dust too.

Finding the maple ply might not be so easy either.

I will explore this because making the jig is they key.

Ian

Joe Alesi
08-11-2008, 06:40 PM
Horn crafting.

I always wonfered how to create the horn flare and machine i wood.

Here is one way used by a professional in HK


Hello Ian,

I have thought about the same issue and a solid chunk of timber is nice, but requires the sort of specialised jigs you show or CNC machining.

Another possibility, if you can find one large enough, is to use a large wooden bowl perhaps 700-1000mm in diameter and cut it into quarters. OK- you don't have a great say in the profile, but the constuction is much simpler as you just need to glue on straight sides for a 90degree flare. Then to make the whole thing "like a rock" fill the dished top and bottom with filler/timber whatever- even polyconcrete.

PS: I'm still looking for the bowl:D- in the meantime I thought I might settle on a large commercial horn flare (pref. in Australia)....looking looking...

Best
JA

Zilch
08-11-2008, 08:33 PM
http://audioheritage.org/vbulletin/showthread.php?t=14933

Hoerninger
08-12-2008, 12:51 AM
http://www.audioheritage.org/vbulletin/showpost.php?p=111362&postcount=9

Ian Mackenzie
08-12-2008, 02:09 AM
Thanks for the links.

I think it prudent to try a few different horn types of commerical origin before spending much effort on a diy horn for the JBL 2435.

If I can get some sense out of DDS I will try one of those and one of the Peavy Quadratic horns and maybe a Le Leach flare.

The plan is to try a CD and a asymmetric horn and evaluate them if possible.

It seems to me that it takes like a panel beater to get a usable response with the Bi Radials and the lesser PT wave guides while shearing off valuable sensitivity.

I mean I have seen smoother on axis unequalised response curves out to 16 khertz on other types of horns with no fall off below 1000 hertz and claims by users they image beautifully and have enormous stage depth. Makes you wonder what all the CD fuss is about. I guess recording engineers who chose Tad monitors worldwide for the past couple of decade can't be entirely stupid.

http://www.geocities.jp/arai401204/Horn/A290/A290.html

The question is CD really worth it?

Perhaps for some people but not for everyone.

I suspect the large majority have not heard a really good horn system because of the way commercial realities impact on consumer products that are shall we say affordable and have good WAF.

Like most things there is no free lunch. Its come down to what is more important to the individual.

The Quadratc horn paper provides a very good plain language outline of the why's and wherefore's of various horn types. The Bi radials are far from perfect and I suspect what JBL now uses in their consumer gear is far from what they started out with.

On the diy front there seems to be more or should I say simply better horns (diy horns) around based on the 2 inch throats so I may also try a 1.5 to 2 inch adapter in the absense of an actual consumer JBL clone and see what happens. There are also some excellent 1 inch diy wood horn designs suitable for 1000- 1200 hertz crossover points.

To date the 9800 and the other JBL consumer horn? appears the only worthwhile JBL horns I have seen apart from the 2532.

Although the fact that Mr Widget appears to dislike the 9800 horn suggests spending weeks making a horn out of wood might be better spent on a Tad horn design or a variant thereof.

As I have stated from the outset the horn is the key and really good horns are few and far between and very very expensive.

Ian

Hoerninger
08-12-2008, 02:26 AM
... so I may also try a 1.5 to 2 inch adapter ...
Think it over as it will give more directivity at the upper limit of the driver-horn combination.
__________
Peter

Ian Mackenzie
08-12-2008, 02:58 AM
Hello Ian,

I have thought about the same issue and a solid chunk of timber is nice, but requires the sort of specialised jigs you show or CNC machining.

Another possibility, if you can find one large enough, is to use a large wooden bowl perhaps 700-1000mm in diameter and cut it into quarters. OK- you don't have a great say in the profile, but the constuction is much simpler as you just need to glue on straight sides for a 90degree flare. Then to make the whole thing "like a rock" fill the dished top and bottom with filler/timber whatever- even polyconcrete.

PS: I'm still looking for the bowl:D- in the meantime I thought I might settle on a large commercial horn flare (pref. in Australia)....looking looking...

Best
JA

Hi Joe,

I dont think its a difficult as it appears.

There are other approaches as well:

http://www.geocities.jp/arai401204/Horn/A290/A290.html

http://www.geocities.jp/arai401204/Horn/A290S/A290-S90.html

This would make a nice project over our summer.

I imagine that its a case of finding a commercial shop or a retired wood turner / crafter will all the tools in his shed and let him loose.

I would be happy to offer the right person locally serious money because it really is a messy business and there is a lot of room for mistakes as in this is not a weekend job.


Ian

Ian Mackenzie
08-12-2008, 03:25 AM
Think it over as it will give more directivity at the upper limit of the driver-horn combination.
__________
Peter

Peter , I appreciate you thoughts.

At this stage its about choices and really trying some different approachs in the practical sense.

Nothing has to be perfect at this point.

People who get uptight and close their eyes at the early stages sometimes miss an opportunity and end up listening to sheer crap for their entire lives.

I wont be trying to shoe horn if you will excuse the pun the end result based on what I might have right now as far a drivers goes.

That was in certain respects the situation with May and its still going.

As you know the 2435 is in effect a throatless affair. Any form of exponential or hyperbolic throat is going to effect directivity but there is more to it than meets the eye. The 2435 reponse above 10 khertz is not text book anyway so that may not be so important.

As things progress if I need to I can turn a customised throat adapter on lathe or if it proves necessary just buy a pair of 2 inch drivers to suit the horn I like.

In so far as the whole directivity thing is concerned its overblown from the earlier days of the PA horn directvity thing imho not well understood in the application of audio in the home.

Forget about horn speakers for a moment.

I have a set of very good 2 way Dynaudio speakers. The tweeter has nice power response.

I have a nice pair two way near field monitors. The tweeter has a wave guide with a dual concentric lenses on the diapgragm that very much restricts the HF dispersion pattern from 2-3 khertz up.

I would be guessing but the angle is in the vacinity of 90 degress or less and narrows coverage at the highest frequencies further.

There is simply no comparison in terms of imaging with the latter, its far superior.

What is interesting is the Dynaudio images best (but poorly) when only slighty toed in.

The nearfield monitors (used at 2 metres) work superbly when toed in almost on axis.

So the notion of wide dispersion and loudspeakers that flank front on into the home listening space might be an old accepted idea but not one that was well understood.

From what I have read broardly and I am no expert if in fact you want a system that images then the interactions in terms of reflections above 1000 hertz with the room become very important. Restricting the coverage angle and toe in of the loudspeaker in towards the listener then makes a lot of sense unless you are prepared to spend a fortune on room treatments and end up with a very technical room aeshetic. Earl Geddes has discussed this at length but people not get it because they are so swayed by convention. Limited information is described in some of the K2 manuals .

There is no rocket science in any of this but the devil is in the details.

Ian

Ian Mackenzie
08-13-2008, 06:53 AM
Enough Talk,

The ultimate plan is to obtain a Tad 1601a woofer and run it with the 2435 Be using either of these horns then obtain a 2nd pair of 1601a like the TSM-1: I think that will qualify for an E2 inspired loudspeaker.

The project will span the next 6 months while the horns and enclosures are fabricated.

http://www.geocities.jp/arai401204/Horn/A290S/A290-S90.html

Andyoz
08-16-2008, 06:45 AM
I came across Lorantz when doing broad search for suitable woofers. Michail Brarabasz the MD of Lortanz responded to an email for information and advised he can spec make a woofer to Tad or better of his own design as a result of demand from the local market and is planning to provide a suitable CNC wood horn.

Sorry to come in so late but I actually tried to get a job with Lorantz when I first graduated in the early 90's.

They are what I would call "...The Quiet Achievers"

Ian Mackenzie
08-16-2008, 07:09 AM
Sorry to come in so late but I actually tried to get a job with Lorantz when I first graduated in the early 90's.

They are what I would call "...The Quiet Achievers"

I cannot comment further other than I was advised ultimately that I was up for about $2000 in start up costs to replicate a Tad driver.:blah:

My guess is that if they figured they could make something that did not break it qualified as being better!:biting:

If money was no object I woud fly Rich out here as as Head of Fabrication between cold showers....LOL

Joe Alesi
08-16-2008, 07:14 AM
Hello Ian

Another possibility- not sure if you have already mentioned/seen these:

http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=270263471083&_trksid=p3907.m32&_trkparms=tab%3DWatching

http://www.fostexinternational.com/docs/speaker_comp/Wood-Radial-Horn.shtml

Best
JA

Ian Mackenzie
08-16-2008, 02:44 PM
Hi Joe,

Yes I was monitoring those and thanks for the link.

No doubt many have gone before me but I would like to explore making some of the 290S.

I do like this set -up..something to aspire to.

http://homepages.slingshot.co.nz/~audio/fatboys%20Tone%20review.pdf


Ian

richluvsound
08-17-2008, 01:02 AM
Ian,

those are stunning. The horns look like originals. laminated maple. I really like
widgets resin clones though. Knowing what it would cost to make, widjets are very very good value indeed . Tad cook the maple to remove the moisture from the timber then re-machine it to remove the scorched bits. A hell of a lot of work

carved from a solid block they would dry out and split.

If money were no object I'd come and build two pairs !

Rich

Ian Mackenzie
08-17-2008, 05:26 AM
Hi Rich,

Thanks for the insight.

Why not come out for a summer vacation, blonde's, rock concerts its all here.

Mr Widgets horns are no doubt nice but far to heavy for shipping.

Shipping those wood horns on ebay is $400. If they keep relisting them I might get excited.

The woofers are on the immediate agenda.

Following several emails from Yuichi in Japan I think it is quite doable to make a wood horn out of suitable lumber.

I am no woody but we have hardwoods available locally and some imported timber specialist

This link is one way of doing it.

http://www.geocities.jp/arai401204/Horn/A290S/A290-S90.html

From viewing another local forum is would seem at least a few guys have carved these horns here and in NZ. I need to talk to them about their experiences.

Ian

Ian Mackenzie
08-25-2008, 05:25 AM
There is a possibilty I might acquire some Tad 4001 drivers.

If the deal happens it will mean I have have at least a means of verifying the performance of the 290 horns by Yuichi as those particular horns were designed to match the Tad 4001.

Pending how it all comes out I may end up running two Tad 1601a woofers per box. Alternatively I may run a Tad 1603 actively as an optional modular helper woofer for movies. I am not mad keen on using large iron core chokes for creating passive filters for helper woofers. Such are the restrains of the marketing department.

There are several commercial offering including this monitor by G.A in the lower image. Its actually quite clever.

These are just ideas but by extending the concept beyond a simple two way the system has more universal performance.

Hoerninger
08-25-2008, 06:06 AM
Ian, as you are thinking in public, just some added brainstorming:

... a Tad 1603 actively as an optional modular helper woofer for movies.Formerly I was always affiliated with the concept of one speaker system for each channel - fullrange passiv, plug and play. Today I reconcile with the idea of one (to four) subs, Harman has a paper on the subject. Main speakers and sub placements demand apparently different approaches.
This can make the mains smaller, although the G.A. monitor is quite nice I admit.

I am not mad keen on using large iron core chokes for creating passive filters for helper woofers.Running active I do not see the need for large chokes, active filter design should be straight forward (class D?).
____________
Peter

Ian Mackenzie
08-25-2008, 07:12 AM
The E 2 is active and it runs chokes but as I said that was probably influenced by other than technical input.

I agree the sub low frequencies are better distributed. One company over here VAS makes an AV widescreen support that is in effect a sub with distributed output.

However what my mind was toying with is in essence an Everest type layout but running the two woofers with several possible modes of operation as in parrallel up to the first crossover point of 650 hertz side by side, or as one woofer or as one helper woofer tuned to B6 alignment.

For movies the last option would perhaps have appeal for ELF extension while for heavy rock the first option would be interesting.

In its purist form of the 2nd option running one woofer unassisted would my taste in using smaller very hi quality amps where an 8 ohm load is preferred.

Ian

Ian Mackenzie
08-28-2008, 03:02 PM
Still trying to sort out sourcing and purchase of drivers..difficult.

I have however been in contact wth DDS horns and discussed the use of the JBL 2435 be driver on their horns. I am going to try one of their fibre glass 110 x 40 horns and see how it goes..

The wood horns are a work in progress and will fabricated a bit later in the year

Ian Mackenzie
09-01-2008, 03:46 AM
A useful inspiration C/- Nelson Pass

Thanks to TimG for the links.:)

http://www.diyaudio.com/forums/showthread.php?postid=1359032#post1359032

http://www.diyaudio.com/forums/showthread.php?postid=1359036#post1359036

http://www.diyaudio.com/forums/attachment.php?s=&postid=1359036&stamp=1195870329

Ian Mackenzie
09-04-2008, 06:19 AM
Here are images of the Emilar horn (thanks to Joe)

Joe Alesi
09-06-2008, 04:45 AM
Hello Ian,

DId you score the Emilar horns?????

Best
JA

Ian Mackenzie
09-07-2008, 12:44 AM
Work in progress.....

Ian Mackenzie
09-19-2008, 06:18 PM
While waiting for part to arrive here are two interesting links;

http://www.studiomaudio.info/onken.html (http://www.studiomaudio.info/onken.html)

http://www.geocities.jp/arai401204/Enclosure/E170/E170.html

There are many interesting enclosures for this style of woofer including a TQWT.

The response of the woofer as seen in the above link is remarkably smooth.

In another forum the distortion of the Tad system was measured and the woofer has very lower distortion down into the bass region.

Ian Mackenzie
09-21-2008, 01:25 AM
Below are actual modelling simulations of the proposed system.

The data was collected empirically and edited into SE.

Based on hard data from the designer (courtesy of Nelson Pass c/- Passlabs CA ) the voltage drives of crossover network have been carefully tailored allowing for the 3d location of the drivers and acoustic response of the raw horn/compression driver.

http://www.diyaudio.com/forums/attachment.php?s=&postid=1359032&stamp=1195870046

http://www.diyaudio.com/forums/attachment.php?s=&postid=1359036&stamp=1195870329


The actual transition from the woofer to the horn is quite sensitive to Z axis (lateral) movements.

Despite the simplicity of the network the actual measured response is very smooth within +- 2.5 db from 60-18000 hertz and the simulations support this data.

If you follow the above links Nelson mentions the design was put together for a business partner. As the story goes the system was put together in diy fashion from available drivers found in Nelson's barn one afternoon. Using a switchable crossover tool box it was found from measured response data that a simple 2nd order high pass network would enable equalization of the Emilar EH-500 horn and the Tad -4001. The rolloff of the driver starts at about 2.5 kertz and allowing for the raw response of the horn / driver the acoustical crossover point is about 750 hertz. More complex networks were attempted to obtain an even smoother response but subjectively they were not as sucessful as the simple network shown. Fortunately the Tad drivers allow relatively straight forward crossover networks and this is perhaps a legacy of the brilliant Bart Locanthi.

http://www.aracnet.com/~bart/bnl2/aesobit.html

http://www.audioholics.com/education/loudspeaker-basics/loudspeakers-when-is-good-enough-enough-part-1

richluvsound
09-21-2008, 04:35 AM
Hi Ian,

I cant but admire your horn in the avatar . Could post some info on here please.

Rich

Ian Mackenzie
09-21-2008, 05:14 AM
Whatever turns you on.

Someone in NZ made it. I'll see if I can get more details.

If you came out here we could go over there and have closer look.

richluvsound
09-21-2008, 06:03 AM
Hey Mate,

I'm just in the process of negotiating my contract at work - Paid holidays and all that. When can you get time off ? We could build those boxes in a week !:D

Build a Jig for the horns and bring it with me :p

Rich

Ian Mackenzie
09-21-2008, 12:53 PM
Difficult question to answer

Ian Mackenzie
09-21-2008, 01:00 PM
Hi Merlin,

You can come too!

Ian Mackenzie
09-21-2008, 01:12 PM
The 1st box I plan to use, the TQWT is not difficult to make as detailed in the sketch of the links above.

The Emilar horn, the Tad-4001 compression driver and the Tad 1601a woofer in the TQWT to form a system as a known quantity. Crossover components must be of the highest quality.

Then I will explore other enclosures and potentially wood horns.

http://www.studiomaudio.info/onken.html (http://www.studiomaudio.info/onken.html)

http://www.tone.co.nz/articles/cracking-a-fat-parameter-sound-58

The Parmenter Fat Boy system appears to be a cloned Tad horn and an Onken enclosure. The builder Jason runs a Hifi business in NZ. That system initially used a JBL woofer (unknown model, probably a 2226) and was updated to the Tad 1601a

That system reviews very nicely. The devil is in the details.

However as you may have gathered I am putting my toe in the Tad water carefully to start with. Experience has shown me things tend to work out better initally by starting off with a guide or a basic set-up and then grow with it.

There could be something in the wings as far as sourcing the key drivers at diy prices for interested members on the basis of my initial system working out. I am also investigating CNC fabrication of a wood horn that could be assembled in component form.

I cannot say more about this until I do some trials but it might fill the void left by Harman Consumer and the delays in obtaining components and lack of suitable horns from Harman.

richluvsound
09-22-2008, 11:27 AM
Hi Ian,

They are handsome !!! There is nothing more rewarding than building a pair of speakers that work !!!! Its amazing the help thats around when one is humble enough to ask for it ! It would be so boring just running around buying the labels to make one feel whole inside ! You have made everything yourself
so far . It will take time but, they will be worth it !:applaud:

Rich .

PM sent :)

Mr. Widget
09-22-2008, 11:28 PM
Beautiful photo...

The horn does look similar to the TAD TH-4001, but the TAD has vanes in it... this one does not. I have no idea how audible a change that might be.

You might want to talk with forum member rloggie. I believe he has had some or all of these parts in his home at one time. I know he has had TAD 4001s and I know he has had that Onken bass bin.


Widget

Ian Mackenzie
09-23-2008, 03:12 AM
Hi Widget ,

Thanks for the pointer.

I am not looking for the ultimate clone of a Tad system at this point.

The baffle size might be an issue in some rooms.

Everyone has their own ideas on the best box like the Jensen Ultraflex/Onken. The same applies to drivers and horns. Some people swear by the older Yamaha compression drivers on Vitavox horns.

I guess it all comes down to what you want to hear.

A lot has been written technically that challenges both the Onken and Jensen approach's but they appear to have a cult following.

The TQWT will be fun but I also plan to try some conventional bass reflex configurations to get some understanding of how the Tad drivers work for me.

I propose to make Yuichi's 290 wood horn at some point because he has verified the performance on the Tad 4001. Yuichi's 480 horn has been designed with and without vanes for 1 inch driver.

Ian Mackenzie
09-23-2008, 03:22 PM
Hi Ian,

They are handsome !!! There is nothing more rewarding than building a pair of speakers that work !!!! Its amazing the help thats around when one is humble enough to ask for it ! It would be so boring just running around buying the labels to make one feel whole inside ! You have made everything yourself
so far . It will take time but, they will be worth it !:applaud:

Rich .

PM sent :)

These are seriously big boxes. I though you wanted a small system?

Below are some links to all sorts of plans and some horn designs

You can use your tad 2002 on the 1 inch horns like Yuichi's 480 horn but the crossover point will be like 900-1200 hertz. In that case the Altec 416 would work but the Tad 1601 would be pushing it .

http://www.geocities.jp/arai401204/Horn/A480FL/A480FL.html

http://www.geocities.jp/arai401204/Horn/A480/A480.html

http://users.telenet.be/philmundi/jbl/jbl.htm

http://users.telenet.be/philmundi/jbl/img/p_onken.jpg

http://users.telenet.be/philmundi/jbl/img/Onken%20360%20litres.jpg

http://users.telenet.be/philmundi/vend/tad/pages/m8_jpg.htm

Some of rloggie previous systems

http://www.audioheritage.org/vbulletin/showpost.php?p=120589&postcount=1
http://www.audioheritage.org/vbulletin/showpost.php?p=91751&postcount=1

The image below blown-up shows what appears to be the Emilar horn.

Ian Mackenzie
09-23-2008, 03:23 PM
I will post pics of the Emilar horn later in the week

Royster
09-23-2008, 10:13 PM
Stunning speakers!

And thank you for sharing your expertise!

felixx
09-25-2008, 12:04 AM
Only two drivers.Simply beautiful.
Very nice finishing,impressive details...oil,colours..everything...I like it.

From your experience,how much $ do you think will cost such wood horns but for 1" driver ...somewhere for 800Hz cutt-off?

Ian Mackenzie
09-25-2008, 01:37 AM
Only two drivers.Simply beautiful.
Very nice finishing,impressive details...oil,colours..everything...I like it.

From your experience,how much $ do you think will cost such wood horns but for 1" driver ...somewhere for 800Hz cutt-off?

You won't find a 1 inch horn that goes down to 800 hertz properly with a 1 inch driver, 900 hertz and 1200 hertz is more usual. The 1 inch compression drivers have limitations below 1000 hertz and there may be compromises in distortion, output and smoothness of response.

The price of wood horns varies enormously and it comes down to specific details, quality and finish. Diy or buy made?

There are reasonable priced 800 hertz wood horns sold by diy loudspeaker vendors. There are people on the internet that made such horns too. You need to explore if they meet your requirements.

Cheap wood horns are not an indication of quality

Wood horns on Ebay tend to be costly.

http://www.ta-on.com/cyabinet-menu/framepage2.htm


Consider one of Yuichi's 1 inch diy wood horns and an Altec 416 GPA woofer.

felixx
09-25-2008, 09:05 AM
My thoughts is for Altec 414-16B + 1" or 2" driver in wood horns.The horn need to go down to 1khz...1,2khz,based on this measurements,what do you think?
http://www.audioheritage.org/vbulletin/showthread.php?t=18913&page=13
There is also Jensen cabinet for 414....12".
I have already the 414-16B woofers and Altec 806A into 811 horns.
Do you think is a proper way to change the 806A with an extended one,or to go upper with a help of a supertweter?...from 12khz upper...

Ian Mackenzie
09-25-2008, 01:01 PM
My thoughts is for Altec 414-16B + 1" or 2" driver in wood horns.The horn need to go down to 1khz...1,2khz,based on this measurements,what do you think?
http://www.audioheritage.org/vbulletin/showthread.php?t=18913&page=13
There is also Jensen cabinet for 414....12".
I have already the 414-16B woofers and Altec 806A into 811 horns.
Do you think is a proper way to change the 806A with an extended one,or to go upper with a help of a supertweter?...from 12khz upper...


This is something you need to try for yourself, measure and also listen.

My suggeston is open a new thread on your project and go from there

Ian Mackenzie
09-25-2008, 02:15 PM
This thread has stired up quite a bit of pm traffic about parts and horns in particular.:blah:

If you want to tackle a project like this you have to put in the hard yards on sourcing drivers, horns and other components yourself and figuring out what you want to do. ;)

This is not an overnight or weekend project and at this stage I am not going to make any recommendations about particular drivers, horns or sources of components until I have a full working system.:bouncy:

There are places and people who can help with parts and at reasonable prices but be prepared to do a fair bit of leg work.:)

Ian Mackenzie
09-25-2008, 02:26 PM
http://www.ta-on.com/network/framepage2.htm

Check out the babblefish translation. I don't think they are charge coupled...dang it!

About networkSaying, that suitability of the network which the music signal passes to straight decides system the grade of the whole SP it is not overstatement.
How, the expensive amplifier using even when, using how expensive speaker system, unless network is good, you cannot show either the half of the charm.
Expensive part, good sound? With think, as for the expensive part the good material when it is superior physically to be many, it is certain to become the shortcut which makes good sound. However because every part has the specific timbre, that the same part is used, it thinks that it is prohibited thing.
Combination of the right talent right place is necessary. But it is serious to search the right talent right place, but when… combination succeeds, being attractive, it plays back the natural music of the extent which is surprised.
You think that it is the cause to which also excessive impedance revision makes the stirring impression of music lose. Just what makes impedance physically even does not think, is connected to the playback of pleasant music with. When revision is done too much, there is no stirring impression, because funny it becomes the music which is not the straw raincoat, is.
It is the element whose also wiring part arrangement is important to the sound making. You must avoid the part kind of arrangement which receives the influence of [rikejihuratsukusu] completely. On that, how it tries not to become loop wiring?
Perhaps, experience necessity but… the device of wiring and clean wiring which will be been clear plays back the music above imagining. Until now excessively did not appreciate (excessively sound recording was not good), thinks even with CD that you make about splendid music inquire in that appearance.
When using the unit where the sound pressure differs extremely, for example, when the woofer 95db and the driver 112db being use, the device becomes necessary. Sound pressure difference of the woofer and the driver is also 17db, the fact that level you adjust with just [atsuteneta] is difficult skill. Assuming, if level adjustment was possible, you think that it is not the sound which you can agree upon. As a measure, when (10 db) the attenuation resistance about of −10db is provided on network side, sound pressure difference of the woofer and the driver becomes 7db and sufficiently level adjustment is possible with [atsuteneta] and reaches the point where it can do fine control.
Lastly, it is digression, but… the full range speaker whose sometimes quality is good we recommend that it becomes hearing. You think that speaker system (network) when constructing, important hint is given.

Ian Mackenzie
09-25-2008, 02:34 PM
http://www.ta-on.com/wood_h01/framepage2.htm

And here we have horns.....LOL

The fact that you analyzed the horn which was called the name machine of western RCA and the like thoroughly, found the secret in open factor of horn, open factor (m) function f (x) applied, evolved is HI-α wood horn. The result and high pass deterioration, horn it is ill-smelling, it displaced and gentleness of sound, good quality of the sound coming out today 蘇 it succeeded in making obtain.

'Seeking the wood horn of ideal',…HI-α horn development starts when inquiring about [uesutan] 15A which was called the name machine. As for 15A horn in spite even in the long horn which exceeds 3 meters, the sound coming out being preeminent, horn is ill-smelling the minute dust you do not make feel. Several there was an opportunity which inquires about [uesutanhon] to in addition to, but being in common, it was to be the horn where as for being able to say, the sound coming out is good to everything, plays back natural sound. When today we would like to make this gentle sound revive, it developed HI-α horn. The name machine the horn which such as [uesutan] RCA was called is analyzed thoroughly, the fact that secret is hidden in open factor is found, in the form which the basic design of [uesutan] RCA horn is followed you established and the fact that developed individual arithmetic expression is HI-α horn. The fact that you adhered to the material, adhered to form, furthermore, you excluded the element which becomes with 0 in sound thoroughly, sought ideal and developed is HI-α horn.
Feature of HI-α horn           1) Adopting the fin less.Shield pine sound manufacture starts shaving, first the wood product when putting out horn to world, in the audio boundary still as for the fin indispensable ones makes and though one person me just the fin is not must be horn, you insisted that. Number of people of the multitude are dealt with, (such as 300 people, 500 people and 1000 people it deals with) at the large meeting place and the like, as for the fin you think that in the sense that directivity is expanded it is necessary but…,

Though one person me just, as for the fin insisted that they are not anything ones of the cause of making turbid sound.
If today, also the certain large manufacturer fin less horn thought of that being developed and being sold by subject and tried adjusting, you think that insistence of shield pine sound manufacture was correct.

2) Developing shield pine sound manufacture individual arithmetic expression,Though me as for feature of horn there is the open factor.When the name machine open factor of the horn which such as [uesutan] and RCA was called is inspected, it is found that it is not made with the arithmetic expression which used single open factor. It is exponential hyperbolic and the like, as an arithmetic expression of horn, but with the arithmetic expression which as for this you saw from the side of cutoff quality of horn to the last and makes most profitable, considering the sound coming out, it is not something which is designed.Therefore the name machine the horn which such as [uesutan] and RCA is called has changed the open factor of the respective arithmetic expression delicately. Though me with you paid attention to this point, digitalized this, function (Fx) you actualized the playback of the natural sound where the sound coming out is good by the fact that it adds in usual open factor.3) The zinc alloy metal throat whose loss is littleIn horn, as for the pre- shear which corresponds to the throat section there are enormous ones which exceed the imagination.Saying, that most of energy loss and information loss occurs in this part, it is not overstatement.With shield pine sound manufacture many experiments were repeated, appropriate length of the metal throat was searched vis-a-vis the xylem, the metal throat of the long [me] was adopted from other companies.Also selection of the material produces big effect on music playback. With shield pine sound manufacture, the throat was produced with the metal where over 10 types differ, in the hearing comparing, the zinc alloy which plays back gentle sound without acquiring color, was adopted.4) Adopting the hard maple laminated wood for the xylemIn the torso part of the drum, even excessively it is famous for the maple material to be used and as a main material of the violin.The maple material to be beautiful the timbre 凛 as, there to be the stickiness, you think that because the power which answers to the request where the professional is harsh is concealed.The drum the highest material is made the maple. There to be the stickiness in sound, because deep sound is sent, is.Because this expensive maple material it starts shaving HI-α horn luxuriously with computer integral protection NC LutherThe curve where the precision which either the deviation of the sun/size section is not high completes.5) Adopting the board thickness type of the open part.The fact that it is overlooked unexpectedly is thickness of the board of the horn open part.The wood because sound is kind, is tend to overlook the horn calling, but the horn calling makes the edge of music sweet.Especially, wooden horn makes the extent board thickness which goes to the facilities appropriation open part thin not to obtain, the calling here are big ones above imagining.Therefore with saying, when it makes the open part thick, becomes wastefully not only becoming heavy, style bad and with respect to eyesight is not beautiful.With shield pine sound manufacture, barely in the surface and the underside, without making thickness the open part feel by the fact that the curve can be given, holding down callingAlso the eye which you saw to be beautiful being quiet, it became the horn which has the high-class impression.A certain certain large manufacturer is and, the horn where at the time of the [tsu] the top and bottom part is rather thick it has been sold, but you think as the thing which considers this point.

Ian Mackenzie
09-25-2008, 02:44 PM
http://www.ta-on.com/cyabinet-menu/framepage2.htm

You want boxes

Shield pine sound manufacture individual 'elliptical internal form', the distortion which occurs inside the cabinet, lost [ri] everything, equalized the back pressure of the cone paper, aiming for the rich music information due to accurate air damping and the gentle music playback which does not have the distortion, developed.
Rigidity of the cabinet is raised.The structure which assumes that it is strongest in the power of horizontal direction, is three prism structures. The fact that these three prism structures are allotted to corner everything of the cabinet, is TS structure. Three prism structural itself become powerful reinforcement, the cabinet where it is resistant to the strain and the box calling completes.

NS cabinet internal constitutionhttp://www.ta-on.com/a-ns-01/hokyou2001.jpghttp://www.ta-on.com/a-ns-01/goreen-0001.jpgIt shaves inside each board which forms the cabinet and it can lose the parallel aspect by being packed, hold down the occurrence of the standing wave can.
http://www.ta-on.com/a-ns-01/goreen-0001.jpgIt shaves the board and each it becomes zone uniform without resonance being inclined to the frequency of specification densely due to [mu] thing, playback of natural music becomes possible.
http://www.ta-on.com/a-ns-01/goreen-0001.jpgThe gentle curve which was made on the cabinet side is due to diffraction, the disorder of frequency is held down.

The standing wave is held downThe standing wave makes excessive sound, makes the sound coming out bad. Existence of three prism structures of the TS type cabinet decreases the parallel aspect inside the cabinet, decreases the occurrence of the standing wave.


The [ri] is lostPlease stand in corner of the room, try hearing your own voice. It seems that just a little is plugged…, it isn't audible in the voice which becomes cloudy? Also inside of the cabinet is the same thing. Not only making the sound where sound stagnates in the corner part, becomes turbid, the sound coming out is made bad. The corner is lost, the music playback environment whose form of ellipse is gentle is made.
TS cabinet internal constitutionhttp://www.ta-on.com/a-ns-01/ts1.jpg







http://us.bc.yahoo.com/b?P=lvIMmEKjqOG9kyaTWuyvagZuedswLkjcBZYADyBR&T=1427cg6r4%2fX%3d1222378905%2fE%3d97447847%2fR%3d yahoosrch%2fK%3d5%2fV%3d2.1%2fW%3dH%2fY%3dYAHOO%2f F%3d909442528%2fQ%3d-1%2fS%3d1%2fJ%3d79DAB444&U=12aps2st4%2fN%3dZMilAUWTWUE-%2fC%3d-1%2fD%3dRS%2fB%3d-1%2fV%3d0http://us.bc.yahoo.com/b?P=lvIMmEKjqOG9kyaTWuyvagZuedswLkjcBZYADyBR&T=143flbpbs%2fX%3d1222378905%2fE%3d97447847%2fR%3d yahoosrch%2fK%3d5%2fV%3d2.1%2fW%3dH%2fY%3dYAHOO%2f F%3d3988971312%2fQ%3d-1%2fS%3d1%2fJ%3d79DAB444&U=12b5hgo5s%2fN%3dZcilAUWTWUE-%2fC%3d-2%2fD%3dRS2%2fB%3d-2%2fV%3d0http://us.bc.yahoo.com/b?P=lvIMmEKjqOG9kyaTWuyvagZuedswLkjcBZYADyBR&T=141t2alde%2fX%3d1222378905%2fE%3d97447847%2fR%3d yahoosrch%2fK%3d5%2fV%3d3.1%2fW%3dJ%2fY%3dYAHOO%2f F%3d51623872%2fQ%3d-1%2fS%3d1%2fJ%3d79DAB444

Ian Mackenzie
09-25-2008, 02:47 PM
As odd as it may seem you can see a lot of the above in the Westlake systems.

Anyway some light reading while I attempt to make saw dust.

Ian

Ian Mackenzie
09-26-2008, 08:45 PM
The hardware.

Ducatista47
09-26-2008, 08:58 PM
A lot of the horns I have seen pictured here over the years, perhaps most, seemed to me lightly built. A lot of thin, cast resin or laid fiberglass looking designs and poorly reinforced aluminum castings. These Emilars look serious. I don't know if they will sound like the real thing, but they look the part. Nice stuff, Ian.

Impressive boat anchors, too. How heavy are those drivers?
Clark

Ian Mackenzie
09-27-2008, 04:21 AM
29lbs

The make the 2420's look like jam jars

It will be interesting when its all bolted together.

The next step is to fabricate a brace to support the driver

As to the end result well time will tell.

But the people in the know tell me its a nice horn for this driver.

Edit: A just trialed one driver/horn in a mock-up.

I think its going to be really good..did not sound like a horn..very open and transparent.

Will report more over the coming week.

Not used to the massive hardware..the driver hanging off the end makes the horn look small

Ian Mackenzie
09-28-2008, 05:03 AM
These pics do not portray the sense of scale very well but you get some idea. While these drivers are not new, the way they are put together is no nonsense. When I set it up the horn throat will be carefully aligned with the driver.

macaroonie
09-28-2008, 09:54 AM
If you take that horn off down to one of those water machining specialists they will be able to cut it in half (horizontally) with minimal material loss. After that you can take a resin mould of the two halves and clone away to your hearts content. The original will be easily repaired with cryo adhesive and you will scarcely see the join.
Richard knows all about the resin thing esp the resultant non ringing horns.
Just a thought--- Mac:)

Ian Mackenzie
09-28-2008, 12:16 PM
That won't happen.

There is no need to clone this horn.

Look hard enough and you will find them.

Same applies to the drivers.

As to alternatives I am still planning to try the Le Leach horns (Azurahorn) at some stage

Woody Banks
09-28-2008, 04:48 PM
Howdy Ian

You have probably already spotted these horns, but just in case. http://cgi.ebay.ca/Wood-Horn-for-TAD-TD-4001-4002-JBL-ALTEC-2-Driver-TSM2_W0QQitemZ290263304281QQihZ019QQcategoryZ73372 QQcmdZViewItem

Woody

Woody Banks
10-05-2008, 09:40 AM
I spotted these teak beauties on DIY forum page.

Ian Mackenzie
10-21-2008, 08:53 PM
Woody,

There are lots of traps for new players here..expecially if you value what looks nice.

http://www.soundstage.com/revequip/opera_m12.htm
http://www.opera-consonance.com/products/M15.htm

This thread apears to be capturing the attention of a few would be speaker builders and while something may look nice it may not sound nice.

Here we see Opera who have gone forward previously (China) and are capitalising on such a design for low powered amplifiers.

The boxes are unlined and not well braced but people like the look of them. The crossover point is also high for a 15 inch driver of unknown origin.

It reminds me of another brand cloning a JBL / Westlake idea.

What makes it so enticing is that the small value amps add so much of their own flavour the would be box builder can paint his own wagon and make all sorts of claims.

The exact details of the horn are unknown ..as also the driver is unknown but it looks nice.

Of course some people have absolutely no idea how to set up even a properly engineered loudspeaker so one may ask what is the point.

I have not heard the box in my avator and while I agree it looks nice there are some issues.

The large dimensions of the baffle and side panels invite box borne resonances and the large side vents modify the scientifically correct bass reflex function due to significant fictional losses. So what do you end up with? Well Murphy's law says the box will add something of its own.

I think the functional appearance of the more contemporary consumer JBL systems like the S4600 & S4800 make a lot more sense

Initally I will build the QWTB as mentioned above and then look at a classic Tad style box for a single woofer. Technically its a better approach within minimal front baffle radiating area and the ports do what they are supposed to do. The interior space occupied by the horn within the main enclosure helps break-up the potential for internal resonances. The box dimensions and panels also conform to more idealised proportions.

What really I like about this box is its practical and its proportions allow movement within the listening room to fine tune the system. Better to build a box that is going to be listened to than a chest of draws weighing 300 lbs!

I am not saying the Fat Boy is not a good idea, its just that using that box add another set of unknowns.

Ian Mackenzie
10-24-2008, 06:46 PM
Here is a very interesting and well written article on a DIY speaker.

The system uses the Tad 4001 on a Tad horn with a focal woofer loaded with a tractix from 120-500 hertz. Other woofers such as the Altec 416 , the Tad 1601a or a JBL 15 inch woofer could be used.

What I like about the article is the decision process they went down to determine the design.

Ian

Ian Mackenzie
10-30-2008, 06:35 AM
There has been some activity on various forums wanting to obtain the schematic of the Tad TN-2 passive crossovers.

After some research and development I have re created the filter.

Tests and modelling confirm the accuracy of the specifications against response measurements obtained from Tad data.

The particular filter topology is rather unique and its application is rather clever.

I must say Tad were way ahead of there time in repect to crossover network design

As this is proprietry data and to recover my costs in parts and time I will not be publishing the full schematic for the notch filters or the values .

For those interested enquiry via pm for further information.

Ian

Ian Mackenzie
11-08-2008, 06:09 PM
TIME OUT

Not a lot happening while I wait for woofers and a gap in time to look at all this again.

However I recently looked at alternative woofers and the driver selections chosen by designers of other 2 way systems.

Then after ready Earl Geddes paper on his two way systems, drawing the distinction between alternatives became a lot clearer once an appreciation of the listening room is considered.

http://www.gedlee.com/Loudspeakers.htm

I think traditionally people focus on woofer LF extension , sensitivity, X max , power handling trying to find the ideal driver that does all things well.(1)

This kind of micro analysis is okay except it does not take into account the real world and the very real compromises that exist.(2)

What happens in the real room?
How big or small is the room?
What is the system going to be used for most of the time?


(1) From my extensive search I have distilled down woofers into some basic categories in terms of 12 or 15 inch woofers.

Sub woofers or extended range woofers that err on the side of sensitivity and mid/Hf bandwidth for maximum LF extension. Great for low bass but not really suitable above 500 hertz.

Low frequency woofers where there is a nice balance of sensitivity, extension and Mid/HF bandwidth. A good all rounder of mid range sensitivity ie 93-94 db 1 watt sensitivity and does not need a really large box. But some drivers of marginally higher sensitivity need quite large boxes.

Mid / bass woofers where sensitivity and Mid/HF bandwidth is given priority over LF extension. Pro woofers tend to fit into the range, low power compression, maximum sensitivity but little low bass extension for domestic use. 97-98 db 1 watt sensitivity.

I plugged a lot of T/L parameters in Bassbox and looked at the driver applications and other things like T poles and flux demodulation rings.

Is real low bass extension really that important when weighed up against mid band performance and sensitivity for a 2 way system?

I dont think its as big an issue to one might imagine.

But obtaining real extension below 35-40 involves a lot of compromises in terms of sensitivity and Mid - HF response for a single 15 inch woofer. Two woofers or a help woofer means a much larger box, usually twice as big.

On exploring the Mid / HF performance it becomes obvious that a 15 inch woofer can provide very good mid band performance if designed carefully, but like an extended LF woofer forget it.

So in Bass Box I plugged in several Mid / Bass woofer candidates (Tad 1601a. AES 15M, B& C woofer as used in the Geddes system) and then applied the Colloms room gain curve.

All these woofers use either Alnico or elaborate Ceramic motors and suspensions to reduce mid band distortion.

In each case the response with room gain was flat to 40 hertz . ie at room / floor boundary.


(2) Then I painted mental picture from the Geddes paper.

In the case of small rooms, the positioning of the loudspeaker is important in terms of obtaining the correct imaging and LF response. ie less then 25-28 sq metres getting the bass response to work properly is not a simple problem.

In this respect a large box is going to be a problem. ie over 220 litres

Apart from the whole imaging issue which is what the Wave - guide is about Geddes pays a lot of attention to power compression for low distortion and distributed subs for assisting with room modes.

Therefore Geddes uses several subs of varying bandwidth to overlap the mains.

This got me thinking that as mentioned above, a 40 hertz mains target is not a big deal if subs are dedicated to that role, particularly for Home Theatre.

In this case the mains could be used as front in HT setup and limit the LF to the mains.

But the real point here is you dont need massive main boxes which are otherwise needed for a system of reasonable sensitivity. Familiar examples are the JBL 4350, 4345.

The focus can then be applied to obtaining very good mid / bass performance and low power compression from this type of driver.

As I have two idle 2245s this could prove an interesting option.

Ian

Ian Mackenzie
11-13-2008, 05:09 AM
Well it looks like I should have the woofers in early December.

The Tad prices have risen due to the weakening US dollar and the list price is now US$810 each. Add to that movements in the exchange rate and you have some very expensive hardware.

I am going to buy a pair of used drivers, regauss and recone them.

If I like what I hear I will probaly buy 4 new Tad 1601a and put two on ice.

Some people have asked would I consider the JBL 1500AL. The answer is no.

Its a totally different kettle of fish and is dedicated to a specific JBL system. The air play from our European counter parts tends to confirm this. Hence I am being conservative with my initial throws at using Tad.

You just cant throw a bunch of SOA drivers into a diy effort, clone or otherwise and expect a $60K sound. If it were that easy JBL would not be in business.

I may also trial a pair of the AE TD-15M Lamba drivers pending how the Tad 1601a's work out. The Lamba driver is more sensitive, takes more power and has more Mid/HF extension but does not have the LF extension of the Tad 1601a.

This is trade off is true of all drivers when balancing sensitivity with LF extension.

The AE 15M woofer is close to 98 db while the tad 1601a in a system is c
lose to 95 db.

So the AE 15M will go louder in terms of mid band efficiency per watt and is rated at 3x the thermal wattage but as you can see has limited output below 35 hertz and 6 mm Xmax.

While the Tad 1601a will produce full power down to 29 hertz and is only -3db at 35 Hertz while the AE 15M is -6 db down at 35 hertz.

The ideal is 2 Tad 1601a per box and that may happen at some point.

The important thing is both woofers are both engineered for fairly straight forward crossover network functions and they are both very clean drivers

Joe Alesi
11-13-2008, 06:05 PM
Hello

Great to see all the detail you are posting on your project:applaud:

I can see you are still on the hunt for the TAD woofers...another possibility if supply is limited would be to try the older JBL 2205. I have heard it said that the TAD was modelled after the 2205 ( I don't know how true that is..I have my doubts).

Still SOME of the specs are not too different, the free air resonance and VAS are very similar. The power handling is different 150W v 300W - although measurement methods used never make this ultra clear. Q 0.22 v 0.3. There appears to be a big difference in Xmax though and the efficiency (1.8% vs 3.5%)

I'm not sure that this would make your woofer quest any easier...you never know. It may be interesting to model them against the TADs.

Ian, I don't recall...Are you goining for a horizontal pair of woofers or vertical arrangement...MTM etc..?

Best
JA

Ian Mackenzie
11-13-2008, 10:27 PM
I am only used one woofer per box initally.

johnaec
11-23-2008, 03:27 AM
Is this system using TAD drivers similar to what you're designing: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=160299355653&ssPageName=STRK:MEWA:IT&ih=006


John

Ian Mackenzie
11-23-2008, 05:19 AM
Wait and see.;)

Ian Mackenzie
11-24-2008, 05:30 AM
As a result of servere shifts in pricing and foreign exchange rates I wont be proceeding with this project basis of the previous discussions.

I just dont see the sense (any sense) in spending AUD $2000 on just two woofers right at the moment.

Okay it breaks a religious tie with using Tad but so what.

Therefore a panel of other drivers has been drawn up and data /response characteristics compared. Discounting the black magic of what may or may not be a great woofer the Altec 416, 515 from GPA and the Acoustic Elegance (Lamba) 15M appear to perform similarly expect for maximum displacement.

The JBL 1500FE also looks good on 3.5 ft 3 tuned to 32 hertz as in the 4800. I have no idea if the 1500FE is available or the pricing of it or GPA drivers. I expect the landed price to be in the order of the Tad 1601s.

This narrows it down to the Lamba driver.

The B & C 15TBX100 is another option (as used by Earl Geddes in the Suma)

The simulations allow for some conservative room gain.

The intent at this stage is to explore the Big Blue project mentioned earlier. This design featured a Tad horn, Tad 4001 driver, a Focal 15VX11 15 inch woofer (which is NLA) in tractrix mid bass horn and is reflex loaded. Its like compact VOT on steroids.

I have shared several emails with Christian Rintelen the designer who has been very helpful with some details.

http://www.nutshellhifi.com/library/europe.html


On paper it has 100 db sensitivity and in room response to 35 hz (-f3).

It was well reviewed in Europe at the Triode Festival in 2004. Any loudspeaker that gets the thumbs up from those guys has to have something going for it.

Its is just a proposal at this point but a very worthy alternative. My 2245H woofers could always be used for LF reinforcement below 40 hertz.

jbljfan
11-24-2008, 07:21 AM
Pops up here from time to time for approx. $470 U.S.
http://www.harmanaudio.com/search_browse/partlist.asp?BrandId=JBL&MarketId=HOM&Parts=000000000000004338

richluvsound
11-24-2008, 12:22 PM
Hi Ian

have you thought about re-coning a 2227 basket with a 1500 fe kit ?

Rich

Ian Mackenzie
11-24-2008, 12:36 PM
I doubt any one has

richluvsound
11-24-2008, 12:54 PM
Oh dear , and I have 2 2227 baskets hear ready for the same destiny !

Rich

4313B
11-24-2008, 01:19 PM
You can get 1500FE recone kits?

Ian Mackenzie
11-24-2008, 02:31 PM
In any case 2227 baskets are not that common.

Ian Mackenzie
11-26-2008, 02:36 PM
Okay,

After some more analysis on drver selection I am going to trial the Acoustic Elegance (Lamba) TD 15M.

While cost was a consideration in the end the Lamba driver has more features that suit my application and is in that sense better value for money at the present time.

For those not aware the reduction of the AUD cash rate by the Aust Reserve Bank has forced down the dollar from a high a 0.9 to the lows of 0.6. against the US dollar. The end effect of this is a high price and potential for probelms with customs because of the high import cost.

For comparison Lamba drivers are a 50% less then the Tad at the moment and one hell of a lot more use friendly.

What is more interesting is that this driver has some heritage from Altec Lansing in that the cone profile is very similar to that Altec. I did some web searches and it to would seem the Altec cone profile was found to perform the best.

I am sure the forum Altec fans will be pleased to hear this.

TD15M Highlights:
Pro Style Bass-Mid or bass horn
PVA Hand Coated Cloth Edge
Very Light, Stiff, Hand Coated and Sealed Paper Cone
6mm peak xmax, 40Hz~2Khz, 97dB@1w, 8ohm only


There are a number of other things that make this driver comparable to a contemporary JBL driver in the way the motor is set up.

A copper shorting ring is placed on the full length of the pole peice and there are (2) optional aluminium de-modulations rings for further improvements in distortion and reduced power compression. (I have only found these types of enhancements in JBLs top drivers.)

What is quite interesting is that it has a phasing plug that serves several purposes. It acts as a heatsink, it extends the Pole to imrove the performance of the motor and also acts to reduce IM distortion. The pole is 2 1/2 inches in diameter. The MMs is 70 grams and BL is 17.

I will post a link to an article by the designers later on what Xmax and BL mean in relation to driver performance.

There is no dust cap per say and it was found that with such low inductance the driver (0.2 Mh) did not need a dust cap to extend the response out to 4 khertz. The pole is 2.5 inches as I understand it.

Users are advised not to touch the phasing plug under high drive conditions to avoid scorched fingers!

The real draw card is the 19 mm top plate and 25 mm length voice coil. According to the folks at AE with the thick top plate you get a much more broad BL curve than with a thinner plate. The thick top plate also serves to enhance low power compression.

The XMax of the TD15M based on the BL curve and the point at which BL drops to 70% is 6mm apparently

Under test the driver has a good power response out to 2 hertz as a result of the cone profile..

On paper using an extended alignment the -f 3 is 43 hertz. The in room reponse using a modified Colloms room gain curve (a more conservative boost of only +2.5 dB at 50 herts increasing to +3 db at 30 hertz) the f-3 is 33 hertz using a 7 cu ft enclosure tuned to 34.6 hertz

The thermal limit is 133 db and max output as Fb is 128 hertz

Sensitivity at 1 watt is 97.8 db

This allows the enclosure to be placed near the wall floor boundary without the usual bloom that you get from an maximum flat alignment. If more ELF is required the mutiple 2245H will come into play.See graph below.

Is this an E2 inspired loudspeaker ..well I suppose it is ..on a bugdet.

More later.

4313B
11-26-2008, 03:07 PM
Pops up here from time to time for approx. $470 U.S.
http://www.harmanaudio.com/search_browse/partlist.asp?BrandId=JBL&MarketId=HOM&Parts=000000000000004338

I'm glad to see they are trying not to screw over their Dealers at the moment. There was a time there when they were undercutting their Dealers.

If more ELF is required the mutiple 2245H will come into play.See graph below.They are pretty tough to beat.

Is this an E2 inspired loudspeaker ..well I suppose it is ..on a bugdet.As an aside - I suspect that the E2 is the opus. I suppose it is possible that I could be wrong but...

Guido
11-26-2008, 03:45 PM
You can get 1500FE recone kits?

No, these are C8RME150 kits

4313B
11-26-2008, 03:47 PM
No, these are C8RME150 kitsAh! :)

Ian Mackenzie
11-26-2008, 05:47 PM
I did have a look at the 1500FE simulations for 3.5 - 4.1 ft 3.

Its a totally different beast all together to the Tad 1601a and the AE TD15M.

Based at least on what JBL have done the setup in S4800 is the best tuning in 3.5 ft 3 tuned to 32 hertz

Ian

richluvsound
11-26-2008, 11:32 PM
:o:

its the thought that counts Sorry guy's

Rich

Ian Mackenzie
11-27-2008, 01:17 AM
What I was saying is you need to work out what you want the woofer to do and every woofer is different.

Ian Mackenzie
11-28-2008, 12:56 PM
Here is a simulation of the 1500FE based on JBL data with the 4338 tuning cyan (4.1 ft 3 tuned 35 hertz) and the S 4800 yellow (3.5 ft 3 tuned 32 hertz). The other set of curves show the addition of room gain.

The bottom set of curves show the addition of the TD 15M response (Magenta) in its enclosure of about 7 cu ft 3 tuned to 34.6 hertz.

The 1500FE has about 1 db more output in the 35 hertz zone and a bit more displacement below 30 hertz and apperar well suited to a shelved alignment.

The big difference is on overall sensitivity were the TD 15M has about 3 db more sensitivity ref 2.83 volts and obviously the enclosure size is up 100 % .

I am happy to have the larger enclosure as a trade off of sensitivity so that I can use a range of lower powrred class A amps in the 20 -50 watt range

4313B
11-28-2008, 01:03 PM
Compare them to a known entity such as an LE14H, 2235H or 2245H.

Ian Mackenzie
11-28-2008, 01:25 PM
Compare them to a known entity such as an LE14H, 2235H or 2245H.

Here is the 2235 H in red tuned to 28 hertz in 5 ft 3 and an extended bass alignment of 24 hertz in 5.5 ft 3.

It goes significantly low on paper but does not have the sensitivity for the midrange extension of the TD 15M

I guess there is where peope have to make choices.

The other thing that comes out of this is that I can see why people align with the more aggressive tunning of the 43XX series with that big bottom end while the other more contemorary systems are seen as more Hifi.

The bottom curves show the 2235H (green), the 2245H (yellow) the TD 15M and then the TD 15M (cyan). The 2235H and the 2245H are in typical alignments of 5 ft 3 & 9 cu ft 3 tuned to 28 hertz


Edited

Ian Mackenzie
11-29-2008, 07:27 AM
I've been considering the type of enclosure style over a few coffee's today and the profile will basically end up along the lines of the 9800 or a bit wider. I may also look at the Tad style box which is more chunky

The issue being the enclosure volume and positoning the horn at ear height while trying not to have a total eye score facing the listener.

Other than that the fact the the woofer will operate up to 750 hertz makes building the box an interesting exercise. Unlike the 43Xwhere the woofer and mid cone are isolated both bass and mid frequencies will come from the common enclosure.

This can be be viewed as either a very simple issue in terms of a solution or a complex problem.

There is no piont having a nice low distortion driver if that is going to be spoilt by a noisy enclosure

Here is an interesting article and this is where is can get confusing:

http://www.silcom.com/~aludwig/Loudspeaker_construction.html

The problem is all the sound going back into the box is in the form of energy and the energy has to go somewhere.

So where does it go?

Some of it through the enclosure walls (1) and some back out through the driver cone.(2)

Okay that can be dealt with by using a sound absorber like fibreglass.

(1) In the case of the 43XX systems it was a simple matter of bracing the box to make it rigid to reduce LF excitation.

However in the case of the two way we do not won't an excitation of the enclosure in the pass band to 30- 750 hertz or somewhat higher and we want to mimimise harmful sound waves from the enclosure coming back out through the woofer cone.(2)

This is not as simple as it might seem.

According to the above reference and a few others I found the excitation of panels depends on rigidity, density and damping.

Bracing helps raise resonances marginally but raising the density of the panels has a far more significant impact on panel resonance supression.

It is quite difficult for diy person to be able to use bracing to control specific panel resonances without very specialised test equipment. In a B & K article very elaborate modelling and measurment was used to define the 600 hertz resonance problem in a Dali prototype loudspeaker.

Air cavities can also give rise to internal enclosure resonances as can the build up on standing waves. These resonances can be controlled with absorbant materials

Simplying using adequate absorbing material such as fibre glass inside the enclosure goes a long way to sorting these issues out. But the effect of using fibreglass is it absorbs LF energy in the way the port action works and it raises the box volume.

So what I propose to consider first is the enclosure construction material.

MDF is the most common material but it does apparently have some resonance issues unless the enclosure is designed carefully.

I therefore plan to look at Birch Marine ply, barium load plywoods and also HDF or HD3 board.

In addition to structural bracing I also plan to investigate panel damping and there are a number of industrial constrained lay damping systems available in sheet and pad form.

A firm called Acoustica market a range of materials called dampers and absorbers in the form of sheet product and foams for this type of application. The benefit of selectively using specific materials is we can absorb mid and and high frequencies without effecting low frequencies.

The enclosures will probably end up being very heavy:blink:.

This will all take a while to stew over but it beats chew over 13.5 uf capacitors.:D

4313B
11-29-2008, 07:42 AM
This will all take a while to stew over but it beats chew over 13.5 uf capacitors.:DYep, they won't just shut the hell up as advised. I think they may have reading comprehension issues.

Have you thought of building a really nice two-way using the 1200FE and the horn/cd of your choice and keeping the 2245H's as subs? As nice as all the JBL tens are the 1200FE is simply better. I say this because you're going over some of the very things that Greg considered before coming up with the 1200 Array. None of the tens, fourteens or fifteens can do what the 1200FE does and that's why he chose it as the best compromise.

Ian Mackenzie
11-29-2008, 08:04 AM
Yep, they won't just shut the hell up as advised. I think they may have reading comprehension issues.

Have you thought of building a really nice two-way using the 1200FE and the horn/cd of your choice and keeping the 2245H's as subs? As nice as all the JBL tens are the 1200FE is simply better. I say this because you're going over some of the very things that Greg considered before coming up with the 1200 Array. None of the tens, fourteens or fifteens can do what the 1200FE does and that's why he chose it as the best compromise.

It times like this when you wish a 375 would fall out of the sky land on someone's block.

Where's Hancock when you need him!!

I had looked at is and that is a possibility for my next job. Those 4345 boxes are being retired.

The 1200fe is a one hell of a driver but I wanted more sensitivity to run some specifc amps..full range.

In the above sim the 1200Fe is -3 db at 25 hertz in just 3 ft 3 but it will work in much smaller....damn!

I realise I am making life difficult for myself.

If things turn around in the next quarter I will give it a nudge.:)

Ian

Hoerninger
11-29-2008, 09:55 AM
Air cavities can also give rise to internal enclosure resonances as can the build up on standing waves.

In case you have a tall box where the lowest resonance is only determined by its length the following approach may be helpul, as in a bass reflex enclosure the lowest one can hardly be suppressed by a relative thin damping at the walls:
It is suggested to make at the bottom an extra cavity by a board with a slightly damped tube so that it performes as a dampened Helmholz resonator. This extra tube and the rest of the enclosure is tuned differently so there will be no harm. The alinment of the bass is far deeper, so there is no issue.
I have never calculated an example, but it sounds resonable.
Anyway ...


The enclosures will probably end up being very heavy:blink:.
___________
Peter

4313B
11-29-2008, 10:14 AM
The 1200fe is a one hell of a driver but I wanted more sensitivity:rotfl: I thought you might come back with its weakness.

Ian Mackenzie
11-29-2008, 12:43 PM
:rotfl: I thought you might come back with its weakness.

I dont see it was weakness, its just a compromise in using any 12 inch extended woofer.

I doubt 15 watts is a good match.

I have one of the best amps ever, a JLH 15 watter just waiting to be tried out.

Its works well on the 4345 full range but you know the problem with that.:D.

Ian

Ian Mackenzie
11-29-2008, 12:54 PM
In case you have a tall box where the lowest resonance is only determined by its length the following approach may be helpul, as in a bass reflex enclosure the lowest one can hardly be suppressed by a relative thin damping at the walls:
It is suggested to make at the bottom an extra cavity by a board with a slightly damped tube so that it performes as a dampened Helmholz resonator. This extra tube and the rest of the enclosure is tuned differently so there will be no harm. The alinment of the bass is far deeper, so there is no issue.
I have never calculated an example, but it sounds resonable.
Anyway ...
___________
Peter

You mean like a vario vent.

Interesting idea.

matsj
11-29-2008, 04:51 PM
Take a look at Tad TL-1102 if you are going 3 Way.

mats

speakerdave
11-29-2008, 04:52 PM
Take a look at Tad TL-1102 if you are going 3 Way.

mats

It's NLA, unless you know a secret.

Ian Mackenzie
11-29-2008, 06:16 PM
Guys

As I already mentioned I have placed the order for a pair of fully optioned TD 15Ms. It will be some time before I take on any other ideas.

Fortunately AE sell factory direct. All drivers are made (by hand) to order with a 5 day turn around.

Tad woofers are not on the agenda thanks poor stocking (4-6 months) and Bush red ink Inc.

I was going to get Alnico GPA 416-8C's as they are a nice driver but the 416-8C has limited Xmax and power handling so the preference went to the TD 15M this time around.

All those who I have spoken to that use the TD15M hold them in high esteem. They are not an extended LF driver by design but they are noted for very low distortion, lightning fast transients and they take no prisoners when it comes to poor recordings.

I have yet to hear and extended LF driver that performs to my satisfaction in the midrange as a two way design.

For this reason I have opted for focus on the Mid / bass as boosting LF below 50 hertz is not difficult with external augmentation if required.

But you cannot win back the midrange. On the downside a larger enclosure is a challenge but that is where diy wins.

Ian Mackenzie
12-02-2008, 07:41 PM
4345 cabinets for sale not.

In typical diy fashion nearly all my loudspeaker projects have morphed from one design configuration to another.

As luck would have it the current diy 4345 clone boxes that were previously adapted have almost ideal width and depth for the aformentioned 2 way Wild "hi sensitivity" beast.

My frugal calculations indicate that the depth and width the existing 4345 enclosures will satisfy the requirements for the largest of horns to be used so I will only need to modify the enclosure height (Internally with a partition) to obtain the necessary volume which is in the order of a net volume 200 litres +- 10%.

A new baffle with need to be fabricated and bolted down on the current baffle after the being cut out with a jigsaw.

These modifications will allow the current enclosures to be used as test boxes on site for initial measurements and setting up. It will also speed getting the project up and going once the woofers are delivered.

When I am happy with the way its works I will then focus on building new enclosures from scratch. In the short term I plan to trial the Emilar horns and some other horns such as Tad wood horn clones and perhaps an Edgar horn.

Do I feel sad about loosing the old 4345. Not really. I have had a lot of fun with this system over the past 4-5 years and I think I have taken that design asa clone as far as it can be without seriously re engineering the loudspeaker.

The drivers and crossovers have been passed on to very good homes for others to have fun with (I have retained the 2245H..I have 3)

The appearance will be somewhat chunky along the lines of a TSM-2

Ian Mackenzie
12-05-2008, 06:23 PM
Here is another snippet

http://www.angstromloudspeakers.com/det ... _cat_id=76 (http://www.angstromloudspeakers.com/detail.php?id=1571&top_cat_id=76)

Our cabinets are constructed of 2cm mdf and bonded to 2cm 13 ply Baltic Birch plywood. The cabinet is a tri-composite, mass loaded component. Our engineers found that when they bonded 2cm mdf to 2 cm Baltic Birch, outstanding acoustic properties were achieved. The bonding agent, a resonance isolation barrier, is very special; it will never crack or craze; it will never harden or become brittle; it does not expand or contract. It is a superb damping material. The opposing resonances of the
MDF and the Baltic Birch are, in effect, cancelled by the isolation barri

http://speaker-parts.worldomain.net/inf ... php#more-7 (http://speaker-parts.worldomain.net/info/speakers/speaker-cabinets-a-material-history-part3.php#more-7)
http://www.tnt-audio.com/clinica/cabine ... fed_e.html

I am getting showered with Pms.

Please be patient with replies ..thanks

dnewma04
12-09-2008, 07:49 AM
Ian, you made a most excellent choice with the AEspeakers (Lambda) TD-15Ms. 2 of the three best speakers I have ever heard were based on Lambda TD series woofers. I heard them compared to some 1601 variants (I can't say I remember which) and they only time that bass appeared stronger from the 1601 was with the subwoofers turned off and some Bach with big pipe organs was playing. Even then, the Lambda's gave me the impression of being the more detailed woofer and if there was a lack of bass, it wasn't immediately noticeable.

I am planning on using 2 pairs of TD15Ms (w/ the apollo motors) in MTM configuration for my mains.

Also, as pretty as they look in pictures, wait until you seem them in person. :)

Ian Mackenzie
12-09-2008, 11:15 AM
Hi,

I have not heard the Tad woofers (alinico) or the Lamba 15M although I have heard the JBL 1500AL.

The Tad 1601a has the deeper magnet (gap) of the Tad alinco motors while the JBL 1500AL is the expensive way of building a deep gap underhung motor.

I dont have room for an MTM design.

I have simulated the effect of baffle diffraction and baffle step.

With a 66 cm x 79 cm baffle there is a gradual fall off below 100 hertz to about 3 db @ 40 hertz. This should be compensated by apparent room gain in a 7 cu ft 3 alignment

dnewma04
12-09-2008, 12:45 PM
Hi,

I have not heard the Tad woofers (alinico) or the Lamba 15M although I have heard the JBL 1500AL.

The Tad 1601a has the deeper magnet (gap) of the Tad alinco motors while the JBL 1500AL is the expensive way of building a deep gap underhung motor.

I dont have room for an MTM design.


Low ceilings? :)



I have simulated the effect of baffle diffraction and baffle step.

With a 66 cm x 79 cm baffle there is a gradual fall off below 100 hertz to about 3 db @ 40 hertz. This should be compensated by apparent room gain in a 7 cu ft 3 alignment

I believe I am going to make mine fairly modular with the horns and each of the woofers residing in it's own cabinet coupled with spikes. It will actually allow me to try different setup configurations or to just run with a single woofer if my wife has a heart attack.

Ian Mackenzie
12-10-2008, 04:46 AM
What are you going to make them out of?

I am looking at several alternatives for the final boxes.

HD3, Birch Ply or a laminate of ply and a other.

At this point I am almost convinced MDF is not the best option for this type of system. The thing is not many people use anything else and its assumed its acceptable.




SUBSTRATE PROPERTIES

(Typical physical properties when tested to AS/NZS 1859.2-1997)
THICKNESS

Property Unit 18mm

Board Density kg/m3 1200
Internal Bond KPa 3000
Modulus of Rupture MPa 70
Modulus of Elasticity MPa 5500
Moisture Content % 8
Thickness Swell 24 hrs % <3 ave
Screw Holding – Face N 2800
Screw Holding – Edge N 2500


http://www.lenehanaudio.com.au/enclosures.php

dnewma04
12-10-2008, 05:30 AM
Well, this may be a long term deal, but I would like to make the baffle out epoxy granite along with using it to make the horn when I decide on a profile. I have liked 18sound XT1464s and have the 18sound ND1460 compression drivers so I might use those. Still keeping my options open in terms of the horn. If a TAD TH4001 or H9800 CNC file fell into my lap, I'd probably go with either one that I could get my hands on.

Outside of the baffle, I'm leaning towards a combo of MDF and ply with a little fiberglass if I can get my wife to think painted speakers are acceptable.

Ian Mackenzie
12-10-2008, 05:50 AM
Pity you are so far away,

We could share some ideas over a few beers!:cheers:

dnewma04
12-10-2008, 01:34 PM
Not exactly around the corner, unfortunately. But if I were, I'd be sure to have a few brews with you.

Ian Mackenzie
12-13-2008, 05:25 AM
Here is a model I created for the AE TD 15M using an Tad 4001/Tad style horn.

The woofer filter had to be manually optimised for the 36 db octave filters to get all the bumps out.

Despite the apparent simplicity of a two way system the precison required to optimise the response and other aspects of the design would not be possible without the computer.

In the graph you can just see the overlay of the horn polarity reversed with a slight depression in the lower midrange (on axis with the horn). It would have taken an enormous amount of work to get that right given the offset of the horn and the woofer. The Tad people really are in a class of their own when you consider these system were engineered when people were just starting to use computors to crunch numbers for loudspeakers.

dnewma04
12-15-2008, 10:43 AM
Wow. That's something. I would have expected a driver as well composed as the TD15M to be a cinch to work with. Do you have some pre-established preference for a 6th order slope?

BTW, after looking at this some more, I see you are just dealing with the differences in the alignment of the VCs. Are these based on physical dimensions or measurements? I have found that the physical dimensions of the VCs center and the acoustical center can be quite a bit different.

Ian Mackenzie
12-15-2008, 01:37 PM
Correct but you have to make certain assumptions with a model

Its a bit involved.

The steep filter does offer a measure of group delay and it would appear that this is in consideration of the path length differences which are quite critical.

Ian

macaroonie
12-15-2008, 02:21 PM
Hi Ian I am following your journey with interest. Here is my wee helper for you . There is a Swedish company called QLN. They brought into use what they called Q board or somesuch . In essence it is a sandwich of two sheets of MDF and in between is a visco elastic layer of adhesive ( pva ) loaded with tiny blobs of a very lossy elastic polymer. They borrowed the technology from the world of coach building where the floors in the passenger compartment were seen as a problem.
I had a passing acquaintance with this in the realm of turntables and I can assure you it does have a significant effect.
The visco layer is approx 1mm between the two sheets.
QLN made some pretty tasty if small speakers back in the day.
Beyond that I cannot help you other than to say that to the best of my knowledge QLN are still in business.
I assume it was Volvo coaches.
I think it is time you built some rough boxes to dry run your modelling. Nothing fancy just a cubic volume.
Best wishes Mac:)

macaroonie
12-15-2008, 04:33 PM
http://www.qln.se/index2.php3?page=qboard&submenu=reference

This should set you on a path. They sell the goo to end users or rather they did. Think of it as a box version of Aquaplas :D

Ian Mackenzie
12-16-2008, 12:57 AM
Good idea and its something I will look more closely at.

I have made enquires previouslyabout locally made product and it is obtainable but is very expensive compared to std ply and MDF. AUD$300 per 1.2 x 2.4 metre sheet.

There is also the Green Glue from the USA which is popular as damping layer.

So I am exploring buying a the damping layer and making my own damped board.

matsj
12-16-2008, 01:25 AM
Something like this:
Damping layer SWEDAC DG-U 6 and Damping Glue DG A2

http://www.swedac-acoustic.com/

Some nice Plywood to build from: http://www.fincolorply.com/koskisound.htm

mats

macaroonie
12-16-2008, 02:09 AM
So I am exploring buying a the damping layer and making my own damped board.


Thats the idea !!!!:D

Allanvh5150
12-16-2008, 02:20 AM
Have you ever thought about building a box out of chipboard and then building another around it out of MDF? Stuff it full of fibre glass at it works real well.:)

Ian Mackenzie
12-16-2008, 05:03 AM
Hi Allan,

Can you please elaborate?

Are you saying laminate the particle board to the MDF? What type of Glue or epoxy?

How big a gap b/n the two layers if you are saying stuff the gap with fibre glass?

What thickness of board 9, 12, 18, 25 mm

Ian Mackenzie
12-16-2008, 05:09 AM
Cupboard material research


http://babelfish.yahoo.com/translate_url?doit=done&tt=url&intl=1&fr=bf-home&trurl=http%3A%2F%2Fwww.hsi-luidsprekers.nl%2FKastmaterialenonderzoek.htm&lp=nl_en&btnTrUrl=Translate
http://www.soundguard.com.au/PDFs/news60815.pdf

dnewma04
12-16-2008, 06:01 AM
I think by chipboard, he is referring to OSB (oriented strand board)

http://www.medtimbermerchants.com/_userimages/osb.jpg

It's pretty much replaced plywood for floors and roofs over here in NA.

I read something about this method of CLD, but I can't remember what the properties of OSB that were that were sought after aside from providing a different impedance than the MDF.

macaroonie
12-16-2008, 11:55 AM
When I was using the lam system for turntables ( Ariston ) we laid up sheets of MDF on the factory floor and spread a measured amount over the surface and sat the second board over the top. Nothing fancy at all. The makers give application notes regarding the qty for ideal results No problems at all in fact the layer of 'goo' was remarkably even throughout the sheet. ( We were using this for plinths to good effect. Markedly better than the same thickness of MDF without treatment. Joe public would never see this as the edge was hidden in a shadow gap )
I can see no reason not to use a combo of mdf on the inner as the ballast layer and something better like Birch Ply as the outer.
In conjunction with well applied bracing and / or tension rods you should be in clover. I think one very quickly gets into the area of diminishing returns, and should also be taking a long hard look at the build of your listening area.
Single skin drywall shakes rattles and rolls , and all that other stuff. Now we need Andy.:blink:

Mac

felixx
12-16-2008, 12:54 PM
http://www.holver.ro/index.php?eID=tx_cms_showpic&file=uploads%2Fpics%2Fsph_baufu_09.jpg&width=800m&height=600m&bodyTag=%3CBODY%20bgColor%3Dblack%3E&wrap=%3CA%20href%3D%22javascript%3Aclose%28%29%3B% 22%3E%20%7C%20%3C%2FA%3E&md5=32a8dc9237c142610a4277b5f039d103

http://www.holver.ro/1983.0.html

polar_bear_0104
12-16-2008, 05:55 PM
Ian (and to all the guys contributing in this thread),

Thanks for a most fascinating, well-documented journey. I'm new to DIY and this is an awesome read (like a lot in this forum). Very inspiring indeed.

Keep it coming guys! and thanks for making this forum a great one!:applaud:

cheers:)

Ian Mackenzie
12-17-2008, 03:33 AM
I have contacted Accoustica locally and will work with them to come up with a practical and hopefully affordable solution

There are a lot of ways to do this but a lot of ways of wasting time and effort so I plan to get advice (technical ) which they have.

Please bear in mind I am dealing with a 2 way project and the woofer runs from 30 - 750 hertz or as high as 1200 hertz. This is quite difference to a sub woofer or a woofer box resonance and sound absorber issue.

Looking at Accoustica's product range they have roll form visco elastic sheet product for extensional for contrained layer damping and a board type product for marine applications that is mutifunctional as well as varioys grades of acoustic foams. They also have damping pads for industial applciations and home flooring as well as barrier and isolation materials.

I see the issue as a problem in the 30 -750 hertz range (up to 1500 hertz attentuated assuming 750 hertz crossover point)

We also dont want destructive sound from the box coming back out the big cone area or air born resonances created by the dimensions of the box.

As pointed out earlier we also dont want a noisy box in that zone.

It sounds simple but its not because sound is energy that has to go somewhere. Some of the materials used for industial applications and like marine are grouped as absorber, barriers and dampers.

According to what I have read below 300 hertz the threshold of audible box problems is not as accute as above 300 hertz and it is preferred that the noise is 30 db or more for more below the output of the cone driver.

So in a simplic way I want the woofer to act as if it were on an infinitely large baffle that did not resonate. Just like an open baffle speaker. People like open baffle because they dont sound boxy and because of the directional pattern.

All the box does is stop the rear radiation from cancelling out with the front wave of the woofer. The reflex porting tunes the mass of air / compliance in the box with that of the woofer equivalent compliance and the mass of air on the port to add reinforcement to the woofer cone output. So we dont wont to screw up how the port works trying to make the bax less noisy.

Therefore if we can absorb a portion of the sound energy on the region of interest from the woofer cone before it hits the hard structure of the enclosure cavity the structure is less likely to react and be noisy at those frequencies.

Typically this is more easily done at mid and higher frequencies than low frequencies. But we dont wont to absorb too much bass energy as this will effect the port action. Some of the materials are able to absorb as well and damp the substrate panel and I think this is the key to arriving at a workable solution.

I think the second line of defence is then to select a panel material as the enclosure shell that is inherantly well damped in the region of interest ie 300 - 750 hertz and is rigid at frequencies below 300 hertz. Below this frequency vibration and damping are a function of density and stiffness.

Somewhere on the www there was a good graphic that explained how to deal with sound problems in each region.

It was along the lines of 30-300 hertz stiffness and bracing, 300 -1000 hertz, mass damping and above 1000 hertz coincidence control .

I will see of I can find the graphic.

As you may have guessed I dont think making the box rediculously heavy is the answer to this type of enclosure application.

I have discussed this type of issue (large 2 way system) with some people who have applied some of the above and the results are night and day compared to building a plain box out of mdf or particle board.

This will take a little while to figure out so have a nice Xmas break.

Ian







Therefore applying simple logic one way to stio

cooky1257
12-18-2008, 05:05 PM
Seems to me you're trying to construct a DMT cabinet a la Tannoy.
The 215 consists of a hardwood frame with all panels(35mm front rear MDF, 25mm thick elswhere) attached via a lossy mastic type adhesive( not unlike No more nails).The internal figure 8 bracing runs horizontal across a vertical spine, all panels braced with eachother but whereas the lap joints on the brace are glued with wood glue the parts that meet the walls/top/ bottom again use a lossy mastic type adhesive.
The rear of the bass unit couples to this brace via a blutack type of putty that is stiff at LF but flexible to HF (and absorbs HF energy).

Ian Mackenzie
12-31-2008, 08:09 PM
As often happens with diy audio you get distracted while waiting for other things to happen........

So I started to think about what I listen to most of the time..at least when the main system is not in pieces.

This raises the age old question of pure audio versus the HT sound ie 5.1- 7.1 and how do you work it with the pure audio aspect.

Running enough class A power to heat a NY apartment in the middle of winter (all the time) is also not friendly on the packet or the environment.

For the most part I use seperate speakers for surround (read that smaller JBLs) with a receiver because I regard HT as entertainment and pure audio as late night stuff when its quiet and that special bottle of Port comes out.

Well things are a changing and if the content keeps coming the new Blue Ray lossess audio standards will exceed or at least equal PCM cd red book.

This all converges on what to do about the centre channel. Up until now I have elected to down mix the centre to the front L + R for practical purposes.

Of course HT fanatics will freak out at not having a centre speaker. My attitude is show me a centre speaker worthy of the job.

As the 4345 clones are semi retired and the E2 inspired project will be somewhat more compact I am wondering if a new centre speaker is do-able .

I am going to play with the idea while working on the main speakers (the AE TD-15m + Tad 4001/EH500).

What I might try is a pair of JBL 2123H cones with small vented alignments in a horizontal MTM arrangement much like some of the JBL centres seen in the NEW JBL 2008 catalgue. (now up on the reference section posted 24-12-2008.)

The high frequency device will most likely be a Eighteensound ND1095N driver and XT 1086 wave - guide. With a bit of room gain it will be -6 db at 75 hertz and woof out around 125 db at that frequency. It would have to be setup as a small front so as not to bottom the 2123's. But the real deal is the very seriously low mid band distortion of dual 2123h's .The crossover point will be around 1300 hertz and the 2123H centres will be about 20 inches apart. I am looking at the ND1095N because its the closest low cost alternative to the Tad drivers that I am aware of. It uses a titanium nitride (treated) dome and a polyestrer suspension. Its also a 1 inch exit and the XT1086 is a ready made wave-guide http://www.eighteensound.it/index.aspx?mainMenu=view_product&pid=178

If I am inspired by the results I might then look at a 1000 hertz wood horn like this http://www.geocities.jp/arai401204/Horn/A1K/A1K.html which is a drop dead gorgous horn and would match the larger 290 horns I have in the pipeline for 2009 along with single Tad 2002 compression driver. Matching customised AE TD10M mid bass woofers will then replace the 2123H which will find their way back into a modified 4345 along with the Eighteensound driver and horn.

At least that is the plan.

Also on the drawing board is the question of a suitable HT receiver or processor to route all the 1080p video / HD audio and drive the new Panasonic Plasma screen. I had alook at the Pioneer range and while I have not seen the 9th generation Pioneer screens the Panasonic 2008 range is very close to the 8th generation Pioneer stuff. Black is Black as they say.

I quite like LCD but Plasma better suitable my video needs.

The Integra installer range from parent Onkyo and the Pioneer LX 81 looks interesting. The digital engines in these newer boes are so good to makes sense to use them as the hub of a high performance A/V system

Well that was quite a distraction

A9X
01-01-2009, 05:25 PM
As often happens with diy audio you get distracted while waiting for other things to happen........Tell me about it.


This raises the age old question of pure audio versus the HT sound ie 5.1- 7.1 and how do you work it with the pure audio aspect.I simply have the best mains I can and use then for both 2ch and HT. If I want to use some tube amps to power them for example, I unplug the AVR and use the audio via a switcher/pre (input select and level control). Takes about 30 secs to changeover. I use Yamaha pro poweramps for HT duties and only the DVDP goes through the AVR.


This all converges on what to do about the centre channel. Up until now I have elected to down mix the centre to the front L + R for practical purposes.

Of course HT fanatics will freak out at not having a centre speaker. My attitude is show me a centre speaker worthy of the job.The only centre I would have in a HQ HT would be identical to the mains. If you only need a one or two person wide sweet spot, then in most rooms a centre is not required.

Ian Mackenzie
01-05-2009, 04:02 AM
I have one of the drivers boxes open.

My inital reaction is OMG..what have I got here...Holy F.

Who made this thing. Robby the Robot!

Its a weird thing to say the least..not conventional by any means

Massive is an understatement.

The driver is 380 mm in diameter, 230 mm deep and the maget is 150 mm in diameter and 100 mm high. The top plate is about 20 mm.

Those numbers are not normal.

The cone is a variation of curveliner and quite deep. The rear of the cone is uncoated and appears a stiff paper, no corrigations and the front has a think coating that is slightly reflective. The driver appearance is dominated by the large metal phase plug, there being no dust cap.

Below in the works I can see a deep voice coil former the extends like a long tube in past a massive spider sourrounded by vents into a massive top plate. There appears a thick curved ring of aluminum like a core above the top plate. The basket is solid metal not pressed.

My impression is it obviously not a mass produced driver and has been assembled with great skill and care. The paper cone has been hand spayed apparently while other aspects like the top plate appear freshly turned. The ceramic magnet appears of a stacked approach.

It would appear to be of a design for the engineer with a well equiped machine shop who made it for himself as a a diy project driver.

weight 32 lbs

TD15M - 8ohm
Fs: 34.7Hz
Qms: 5.09
Vas: 312L
Cms: .3mm/N
Mms: 70g
Rms: 3kg/s
Xmax: 6mm
Sd: 855
Qes: .35
Re: 6.6
Le: .2mH
Z: 8ohm
Bl: 17Tm
Pe: 500W
Qts: .33
1W SPL: 97.8dB

Ian Mackenzie
01-06-2009, 04:12 AM
To satisfy my inital curiosity I gave one of the woofers a quick run in a test box tonight with the horn and compression driver on top using a basic 2 way 12db passive crossover


Despite being far from an optimised system the resposne was remarkably smooth and uncolored overall.


The test box is an old 5 cu ft JBL component design tuned to 28 hertz

The correct tuning will be in the order of 7 ft 3 tuned to 35 hertz


The horn and driver is a real peice of work and I expect it will be quite impressive when everything is settled. Likewise there appears a good synergy with the woofer.

I will report more details later in the month.

Ian

Ian Mackenzie
01-14-2009, 05:03 AM
No further progress as I am waiting for suppliers to come back from holidays.

Ian Mackenzie
01-16-2009, 04:26 AM
http://babelfish.yahoo.com/translate...rUrl=Translate (http://babelfish.yahoo.com/translate_url?doit=done&tt=url&intl=1&fr=bf-home&trurl=http%3A%2F%2Fwww.hsi-luidsprekers.nl%2FKastmaterialenonderzoek.htm&lp=nl_en&btnTrUrl=Translate)
http://www.soundguard.com.au/PDFs/news60815.pdf (http://www.soundguard.com.au/PDFs/news60815.pdf)

Okay,

I have given it some thought.

By interpolating the results of the transalation you can see a trend in the various damping combinations.

The problem is to make the panel rigid for non flexing below 300 hertz but this makes the resonance in the 500 hertz region more pronounced in the passband. Concrete obviously damps the structure but its heavy and messy.

Slide 24 shows the effect of adding a mass layer with strengthening and this is a very good result with a reduction of 10-15 db in the 500 hertz resonance area.

The MDF board has somewhat wider band of critical resonance than Birch Ply.

The reason the 11mm mass plate is more effective is its heavier and thicker then the 7 mm mass plate.(1)

The effect of the glass wool is to asborb some of the sound energy and hence reduce the amount of resonance.

From the other slides it becomes clear that the constrained layer of the sandwich improves further damping of and reduces the 500 hertz resonances even more.(2)

So I think there are two levels (1) & (2) that can be implemented.

The problem then becomes how to implement either approach practically with minimal effort and cost.

I talked to Accoustica today and I can obtain some of the damping pad in the 12 mm range which has a constrained layer construction and mass of about 5 kg metre sq.

This would be applied to 50% or more of the interior of a braced 18mm MDF shell to implement option (1). Apply 50mm grade of Acoustic grade foam and this will supress the 500 resonance with a coefficient of about 1.25 @ 500 hertz

I have also looked at the Subdue range of barium loaded birch ply that are available in various grades. The Subdue 709 grade from Pyrotek looks interesting and I will enquire about cost. Purchasing the (2) panels in 1.2 x 2.4 sheet size allows the material to construct 1 pair of enclosures. The bracing would then be added to the panels. The Accoustica foam in 50 mm grade would then be added. An optional layer of the damping pad could be used as additional damping but the enclosure would start to become quite heavy.

The Subdue sheets are on the order of UUD$250-300 each.

I am not in favour of attempting to contruct a sandwich layer of MDF or Plywood.

I expect option (1) would be about 50% less to construct.

Attached below is a concept graphic (courtesy of eighteensound) for box form factor.

Its not nearly as difficult to make as it appears. I like this design because it gets away from the large chunky box look and there are certain structural and acoustic benefits.

However, before getting to engrossed in the final box idea I need to do some mpre modelling and measurement of the AE TD-15M in a test enclosure to confirm its LF capability.

The intent of the overall design is that of a two way with LF extension to 35 hertz (in room response). This will depend on how the driver subjectively behaves in the room and the overall balance with the horn.

The other attachment is a model in Bassbox of the effect of room gain with the enclosure against the front wall and about 1 metre from the side wall.

By using an extended alignment and utilizing the available room gain I hope to extend the -3 db point from 42 hertz to 33 hertz. The effect of the somewhat over damped alignment in a larger box is offset by the room gain and we end up with a relatively flat response.

Why is this important. I could probably live with -3 db at 42 hertz but more importantly its best to try and tailor the response to the enclosure location. Otherwise we end up with a bass hump and only modest bass extension.

This shown in the last attachment where an optimally flat QB3 alignment is compared to the extended alignment with room gain. The effect of the former is extension to 39 hertz and a hump around 100 hertz.

This is typical of what I heard from the JBL blue monitor series when stacked up against the wall in a shop over in Japan. ie 4338. Those systems go lower and the effect of room gain swamps the low end response unless you position the system carefully.

My room has significant modes at around 43 hertz so I am hoping the theory proves correct. Without room gain the reponse is about -3 db at 43 hertz. Room gain lifts the response to flat and extends it to about 33 hertz. This should be quite audible.

This is perhap more important for music reproduction than home theatre entertainment where we want to magnify the bass.

The intent is that this design will be able to be used unassisted for music and with ELF assistance for home theatre. Displacement limited power output is shown in the last attachment with output falling sharpley below 30 hertz while thermal limiting above 100 hertz at 500 watts rms. According to John at AE this driver as very little power compression. Being 97.8 db sensitivity for 1 watt @1 metre I doubt I will ever approach that condition.

Ian Mackenzie
03-05-2009, 04:35 AM
useful parts

http://shop.ebay.com/?_from=R40&_npmv=3&_trksid=m38.l1313&_nkw=emilar+horns&_sacat=See-All-Categories

pos
04-09-2009, 06:29 AM
Hi Ian

So where are you at with these TD15M drivers?

Ian Mackenzie
04-09-2009, 05:14 PM
It will be a while before I post further progress.

I make no representations that the TD-15M will suit everyones needs. It depends on what you are looking for.

ie Its not a replacement for a 2235H but it certainly has some of the hallmarks of JBL's more contemporary consumer LF woofers.

Because of the cost of manufactured constrained layer plywood I am working with a local company to produce my own cabinet matrerial.

If you look back at the earlier posts on box resonances issues "they" tend to be box specific in that there is no generic solution.

Once the resonances have been identified the question is what or which of the measured resonances are going to cause audible colourations in the passband of the woofer.

What I am saying here is there tends to be a situation where diy people go hell for leather on damping a box as in over kill or they completely miss the problem area.

At the moment I am leaning towards an eight sided enclosure with 22.5 degree corner angles. Smaller sections of wood tend to have higher modal resonances and are more easily damped than larger flat sections of wood. Its not difficult to cut specific angles with a table saw and a jig.

It will consist of a woofer enclosure base section of eight sides, a woofer front baffle and a horn enclosure section.

The woofer will be mounted on a flat section of baffle inset into the front face (of three sides) of the enclosure about 30-40 cm from the base of the enclosure.The inset baffle will align the woofer to a 1/4 wavelength with the HF driver at the crossover point. This allows both the LF and HF drivers to be operated in phase. A 3 inch section of acoustic foam above and below the woofer will control diffraction of the inset baffle

Above the woofer the enclosure will assume for same profile of the woofer enclosure with 3 front facing sides. This will allow the curved front of the horn to protrude forward of the baffle

Then there is the issue of controlling internal reflections in the 300-1000 hertz range.

I have been looking at some of the stuff over on a Tannoy user site and they have some interesting approaches to this issue with large boxes.

This will require a degree of experimentation to control harmful standing waves and box noise existing through the woofer cone.

Ian Mackenzie
06-02-2009, 02:15 AM
This project is not dead but there are other priorities right now.

I am confident I have re - engineered the Tad TN-2 network based on actual data and technical information gathered on this network.

Like all horns, this class of Riadial horn requires the right degree of passive equalisation to make it work right (as do all the current crop of TOL JBL horns).

The network has several functions, crossover slopes (36 db and 12 db), attenuation, impedience control and equalisation of specific frequency regions.

Unfortunately most if not all diy efforts using cloned or Tad horns without the right crossover and passive equalisation would leave the user perhaps wanting to search for other options. This is just not possible without a lot of research and powerful software.

The intent is to realise the full potential of the 4001 driver and possibly the 4003 at some point with this project.

Its becoming more obvious to me as I look closer at what Tad have done that they were miles ahead of anyone else in terms of crossover network and drivers for a very long time.

I will post more details when time permits

Ian Mackenzie
07-06-2009, 02:22 AM
I been deliberating over the box for sometime now.

It would seem there is a method in JBL 's madness whe it comes to box shape and construction.

In simple terms a larger panel is more prone to vibrations than a smaller panel over the frequency range that the woofer operates.

Therefore you try and make the box from smaller panels if practical.

In our diy world we do not care are about high production overheads so there are more possibilities and it comes down to skills and tools available.

This in turn means moving away from the rectangular box that typically has large flat panels.

What is interesting is that Vance Dickaason claims that internal reflections are easily controlled with internal stuffing and that external box appearance is more a cosmetic consideration when it comes to controlling internal box reflections.

I guess it depends on how far you are prepared to go.

It is also important to distinguish internal box reflections from box resonances.

I have decided to cheat a bit an use a box a bit like 99XX style enclosure.

The box will consist of 3 sub components.

These link gives an indication of the shape.

http://www.soundlabsgroup.com.au/p/V-5957/Monitor+890+MK+III
http://www.soundlabsgroup.com.au/bildgross/845_bzeichnung1.html



The base/lower section which will be about 12 inch from the floor.

This section will have a hex front section and will have the port at the rear. It will also have the crossover and a massive base to sink resonance from the rest of the structure.

The woofer section will have a flat panel inset and will measure about 24 inches x 17 inches. As the woofer is 15 inches in diameter there is very little left in the panel to resonate.The panel is be carefully damped high density plywood.

The rest of this section will be a hex shape. The inset will be adjusted for phase alignment of the crossover region at a distance of about 3 metres.

The top section will hold the Emilar horn and will be about 11 inches high and will have a hex front section.

Each section will be assembled seperately but with a jig so all the panels fit. A 3/4 inch plywood frame will form a flange for each section to be fastened together.

The idea being that during development I can alter one section without having to discard the whole enclosure.

I bought Linearx Leap 5 & LMS4 recently and will use that package to design/tune the bass system and create the crossover network.

I have two basic ideas for the crossover network.

12 db acoustic slopes with the woofer centre 1/2 a wavelength from the compression driver so both drivers are in phase and classic LR 24 acoustic db slopes where the woofer is aligned to ensure at ear height the transfer funtion is maintained.. Both will have 750 hertz crossover points as a starting point.

I also plan to try an active system. The Passlabs people report very good results with this Emilar horn and the Tad 4001 compression driver in an active configuration.

The Leap package is now a fairly mature product and is so advanced that(despite the cost) I expect it will carve years off getting the system "right" but will probably take a long time to complete this project anyway.

Ian

A9X
07-06-2009, 12:09 PM
These link gives an indication of the shape.

http://www.soundlabsgroup.com.au/p/V-5957/Monitor+890+MK+III
http://www.soundlabsgroup.com.au/bildgross/845_bzeichnung1.htmlDamn, I spent a day drawing up an enclosure for my AE 15's to sit into the corner that is near identical, a fraction wider to accommodate the slightly wider driver and the Unity horn. I wish I'd seen that first and saved some time.

I think it is an excellent choice for all the reasons you mentioned and will look very good with the Emilar on top.

Loren42
07-06-2009, 12:33 PM
I bought Linearx Leap 5 & LMS4 recently and will use that package to design/tune the bass system and create the crossover network.


Sigh. When I am a rich man, maybe.

4313B
07-06-2009, 01:34 PM
That's a nice looking box.

They're running both those twelves up to the horn. :hmm:

richluvsound
07-06-2009, 02:40 PM
Hi Ian,


I hope you don't mind me putting these 2 pics on your thread. They are very much related to your project and would welcome any constructive criticism.

What is the damping in the box does the grey represent a specific product and amount.

All my timber is reclaimed or left-over CREDIT CRUNCH K2 THING

2435. H9800 clone and 2234, 2235, 1500al . Not all three , but will decide on the woof through an extended listening .

Rich

Ian Mackenzie
07-07-2009, 02:01 AM
What is the damping in the box does the grey represent a specific product and amount


Hi Rich,

I think it is common interbond otherwise know as polyester batting as used in insulation of houses

There are different grades..have a chat to Wimslow who sell diy kits.

On the design with dual 12's it apparently has had good reviews.

4313B
07-07-2009, 07:13 AM
On the design with dual 12's it apparently has had good reviews.I'm still deciding on how to arrange four 1200FE's so it's either this way or MTM. Thanks for the links again. Greg checked out the prospect of using two of the four 1200FE's as helpers as per the Everest II and it didn't look promising; Their response is too flat in the range it matters. I tried it anyway and it didn't work out too well. :rotfl: The resistor required across the helper 1200FE is so low it kills off nearly 3 dB of efficiency and that is completely unacceptable.

Ian Mackenzie
07-07-2009, 11:41 PM
I also doubt one woofer with 91=92 db would cut it with that horn so the plus's outweight the minuses.

http://www.soundlabsgroup.com.au/bildgross/845_bfrequenzgang.html

4313B
07-08-2009, 06:24 AM
I also doubt one woofer with 91=92 db would cut it with that horn so the plus's outweight the minuses.Agreed.

Ian Mackenzie
07-12-2009, 06:41 AM
Hi have been reading Wayne's crossover/driver spacing iideas over on Pi Speakers.

The novel ideal of using the lobes to punctuate the vertical dispersion to match that of the horn is quite interesting (ie 40 degrees).

I am not sure about the 700 mm centre to centre distance for a 750 hertz crossover point.

Ian

Zilch
07-12-2009, 10:34 AM
An axi-asymmetric horn/waveguide will lose pattern control in the vertical at a higher frequency than the horizontal. Properly implemented, the nulls may be used to augment vertical pattern control in the crossover region:

http://www.pispeakers.com/misc/Vertical_Nulls.wmv

4313B
07-12-2009, 10:48 AM
Very cool that he made a video! :yes:

Zilch
07-12-2009, 04:17 PM
Very cool the software WTPro developed to present realtime high-res response, too.... :thmbsup:

Ian Mackenzie
08-21-2009, 04:12 PM
I went to order some plywood the other day and the place has shut up shop. The said the cheap Asian product had destroyed the market.:banghead:

I did find some Aust made marine plywood but it was very expensive so I am exploring some other ideas.

In the short term I propose to make an MDF model to test and measure.

Ian Mackenzie
09-04-2009, 06:01 PM
Marine plywood on hand.

The plan mk1.9 is to build a cabinet from dual 12 mm ply with a viscoelastic layer sandwhich.

The cabinet shape will be in the order of 56 x 45 x 120cm (22 x 17 3/4, 47 1/4 inches).

The CLD will help damp the plywood while extensive bracing will stiffen and raise resonance above the passband of the woofer (I hope).

As discussed earlier MDF flat sheet in its raw form has significant resonances in the 300-500 hertz region that are very audible.

Depending on how successful the whole project is and the damping of the plywood I may consider an exterior shell using another 12mm plywood layer with vertical 2 inch stiffeners and rockwool.

After a lot of consideration the layout will be not unlike the 9900...everything is done for a reason.

The approach will allow some flexibility of horizontal driver offset

Depending on the design point for the crossover some adjustment can be made to the offset.

Ian

Ian Mackenzie
09-19-2009, 12:30 AM
The boxes are well under way.

The walls are dual sandwhich 12 mm marine ply and visco-elastic membrane consists of 1.2 mm thickness. The effect of the membrane is to damp the plywood.

http://www.acoustica.com.au/pdf/QuietWave.pdf

The interior dimensions are 118.5 cm (H) x 51cm (W) x 39.5 cm (D).

There will be 4 or 5 tiered frame bracing at odd intervals, diagonal stiffeners and internal partitions to break up standing waves and resonance modes. The front baffle under the woofer will be 54 mm total thickness

Ian Mackenzie
01-09-2010, 03:49 PM
Along with other resources we need an loudspeaker crossover tool box.

To correctly design a loudspeaker crossover network requires collection of data/ measurement and a means of designing and optimising the crossover functions.

This can be done in the analogue domain with passive filters or analogue active filters.

Prior to starting this phase of the system development it is important to have some system goals.

Broadly stated my goal is:

"The idea being to bring to the table a 2 way based system that will deliver a very smooth, coherent and detailed sound not found in the earlier 43XX systems with hi sensitivity, low power compression and very low distortion. Will it be an MTM ? No. Will this be a rediculously expensive project. No.''

Breaking down that goal into specifics ; smooth response, coherent, detailed sound, hi sensitivity, low power compression, low distortion.

Without going into micro detail at this point I need to specify my sensitivity target,: What is a hi sensitivity system? 90db 1 watt, 93 db 1 watt 96 db 1 watt , 99 db 1 watt.

Why do I want a high sensitivity system?

So I can use less powerful amps of very high quality. All things being equal high sensitivity systems have lower power compression and lower distortion and higher dynamic range than the low or moderate sensitivity counterparts. This is / was clearly audible in A/ B comparisons when I visited John Nebel's wall of sound in 2004 and we compared the 4435 to the LRS6332. The LRS system was more accurate in some repects but the 4435 was more life like in its presentation imho. Its was very obvious the LRS system needed far more power for the same levels.

I think 90 db is average for a home audio loudspeaker and 99 db is very high in the PA category. A more meaningful measure is the amount of power required for a specificed acoustic output at 1 metre. A 96 db sensitivity system is only going to need 1/4 of the power of the 90 db system for the same acoutic output.

So if a 90 db system needed a 100 watt amp to produce the require dynamic range then the 96 db system would need a 25 watt amp. When you are operating full biased class A amps these are serious considerations in terms of power consumption and okay global warming!

I do have on hand a 500 watt class A, A/B amp and I propose to use this for the woofer and a smaller fully biased class A amp for the compression driver.

But seriously I tend to believe along with many other people that a properly designed systems of hi sensitivity have better retrieval of micro dynamic and spatial detail.

So I can live with somewhere in the range of 95-96 db 1 watt.

Now the other goals: smooth response, coherent, detailed sound

Fortunately a 2 way design supports the requirement for a coherent sound because there is only 1 crossover point in the most audibly sensitive part of the human hearing frequency range. Just exactly where the crossover point will be and the type of filts is yet to be determined but it will be somewhere between 700-1.0 kertz.

I think +- 3 db for the woofer and +- 2 db for the horn is a reasonable and realistic specification. Smoothness in the 1-4 khertz range is most important. I have not set frequency bandwidth yet. This will be somewhat influenced by my room, particularly room gain. However on paper I would like - 6db points of 35 hertz and 20 khertz

Below and above these points may require some augmentation from an ELF device/ aka helper woofer or a super high frequency transducer. This will be determined by the in-room response and subjective performance.

I am aiming for an in room response of -6 db 35 hertz.

In terms of what components to specify I have decided to use the Acoustic Elegance TD 15M 15 inch woofer and the Tad 4001 compression driver on an Emilar EH 500 sand cast horn.

This particular woofer is underhung design, a hi sensitivity mid bass woofer in the 97-99 deb sensitivity range. Noted that baffle step compensation may shave off 3-4 db sensitivity depending on room gain below 150 hertz.

The Tad 4001 and the Emilar are an known quantity and it is possible to obtain a smmoth on axis response with a simple passive crossover network.This Be based driver should meet the design goals for low distortion and clear detailed sound.

When I have more specifc data and applications recommendations on some of the drivers I will post details.


I have posted again here as plans are in place to start some crossover network design and in room measurements with Leap 5.

The enclosures have been constructed (un finished at this stage) and are ready for mounting of the drivers.

Pics will be posted but the enclosures can only be described as inert and heavy. The 12mm marine ply with damping layer CLD laminate walls and diagonal construction ply partitions have made the whole shell very solid.

No measurements have been made but I expect the goal of pushing the panel resonances above the woofer passband to be met.

The above quote describes the original intent.

As is often the case these projects and stretch out and morph into other things with the flux of time so the quote is a timely reminder to not drift off in another direction.

Outside this particular project I do have other plans for something more exotic but this simple 2 way should prove quite useful.

I mean there should be no real need for biamping and it will run off as little as 5 watts of power.

Later on I will consider augmentation of the bass if suitable woofers become available or even the 2245H asa sub and perhaps a more advanced horn and driver but the under-hung mid bass TD 15M or a horn loaded variation will likely remain. The low distortion, bandwidth and speed of this driver defy conventional wisdom of a 15 inch driver. The 1500AL is about the only other driver I know of that shares similar qualities.The 1500 AL goes lower but does not have the TD 15M sensitivity or mid-hf extension (flat to 4k hertzon axis). The later makes the crossover design a bit more forgiving.

Ian

Ian Mackenzie
01-16-2010, 08:37 PM
box images in progress.

One inch CLD ply.

The bevel front panels above and below the woofer were cut on a table @ 40 degrees. Fitting the horns was PITA due to the weight of the 4001 driver.

The interior shape behind the woofer is like a PA Array Wedge. This was done to help reduce and spread the rear wave reflections and make the panels immediately adjacent to the woofer more rigid...aka the blameless box. Liberal use of acoustic foam will help absorb any rear wave.

The tuning is more like an extended shelf alignment tuning the box to 35 hertz, te woofer having a QTS of 0.33, Vas 307 litres and FS 34 hertz as I recall. The plan is that any potenial room gain from the front wall will add back the response below 80 hertz providing a smooth low end to the mid 30's. The total Xmas of this underhung woofer is only 6 mm so the max acoustic output is limited to 35 hertz anyway.

See full discussion on box tuning here:

http://www.audioheritage.org/vbulletin/showpost.php?p=236194&postcount=153
An interesting articleon making tad drivers
http://www.techradar.com/news/audio/hi-fi-radio/so-what-do-50-000-speakers-sound-like--646417?artc_pg=2

Ian Mackenzie
01-30-2010, 09:41 PM
Continued

Here we have the first draft of the crossover design using Leap 5

I started with the horn first and tried to use a simple 12 db 2nd order high filter.

However because of the bumpy and reactive nature of the horn/ compression driver impedance a simple 2nd order LR filter was not possible. In the end I used a split impedance / response equaliser network which effectively smooths the impedance and horn acoustic response. Tad use a very similar arrangement .

The actual low end response of the horn was more like a 12 db 2nd order slope so I integrated the acoustic response with an electrical 2nd order filter to arrive at a 24 db LR filter (-6 db at 750 hertz).

The response of the overall system (and horn) was on axis un gated at 1 metre from the VC of the driver. The woofer response was smoothed before tail correction and processing.

The woofer network is a 24 db LR electrical filter optimised for the slight rise in the woofer response above 800 hertz that is possibly due to the baffle dimensions.

I wanted to keep the system impedance as smooth as possible and that seems to be okay.

Reversal of the horn polarity indicates good phase integrity at the crossover point.

The dip in the mid bass is a room mode and can be ignored. The bass response appear to be useful down to the mid 30 hertz area.

Ian Mackenzie
02-05-2010, 06:40 PM
Attached is a revision of the crossover topology similar to that used in contemporary JBL TOL systems.

The woofer is 4th order low pass LR electrical filter topology, the horn high pass filter 3rd order electrical filter.

The equalisation of the horn is handled by two series RLC filters.

The smoothness of the crossover transition is the result of Flatness Optimisation using Leap 5. It is unlikely that similar results could be obtained otherwise.

The result is crossover slopes that are unique to the drivers and the 3 dimensional placement on the baffle plane. The filters are more like 6th order acoustic in their ultimate slopes.

Inverting the polarity of the horn results in a deep, sharp notch at the crossoverpoint of 750 hertz. Lateral movement of the horn +- 5cm results in little amplitude variation in the crossover region.

herki the cat
03-23-2010, 01:45 PM
Here is a very interesting and well written article on a DIY speaker.

The system uses the Tad 4001 on a Tad horn with a focal woofer loaded with a tractix from 120-500 hertz. Other woofers such as the Altec 416 , the Tad 1601a or a JBL 15 inch woofer could be used.

What I like about the article is the decision process they went down to determine the design.

Ian

Very interesting decision process. Well, I am curious to know is this Lofty speaker any better than the time honored Altec A7 with a Tad 4001 __ Altec 802-D and 288-series are No Slouches in the A7 family__ Also, as you well know, tractix, despite a slight extension of cut-off frequency, dose present serious phase shift distortion in the bottom octave or so, not inherent in the extremely linear exponential flare all the way down past cut off, which RCA's Dr. Harry Olson & Altec's Dr. John Hilliard always preferred.

Cheers , herki the cat

Ian Mackenzie
03-24-2010, 12:34 AM
Well Lyn Olsen thought it sounded good when to visited Paris.

I guess this is what the art of building loudspeakers is all about.

I mean some designs work far better than they have any right to and the we see some very expensive drivers in other designs and they don't seem to be anything special.

Perhaps

Mr. Widget
03-24-2010, 12:48 AM
Also, as you well know, tractix, despite a slight extension of cut-off frequency, dose present serious phase shift distortion in the bottom octave or so, not inherent in the extremely linear exponential flare all the way down past cut off, which RCA's Dr. Harry Olson & Altec's Dr. John Hilliard always preferred. I don't know which I'd prefer for monaural listening... but for stereo the tractrix horns do tend to create a better image than any exponential horns I have heard. I doubt Drs. Olson and Hilliard gave stereophonic imagining the level of importance that we might today.


Widget

herki the cat
04-05-2010, 01:30 AM
I don't know which I'd prefer for monaural listening... but for stereo the tractrix horns do tend to create a better image than any exponential horns I have heard.].... I doubt Drs. Olson and Hilliard gave stereophonic imagining the level of importance that we might today.
Widget

It could be that in comparing the exponential horn performance against a tractrix, of equal horn length, the tractrix will have almost two octaves of extended bandwidth in the important mid bass spectrum compared to the exponential horn which is unloaded & honking its head off in a nasty mode, while the tractrix, despite some phase shift problems still has decent real loading capability in this spectrum.

Mr. Widget, You are correct regarding Dr's. Olson and Hilliard's low level attention to the importance of stereophonic imagining since their attention was focused on mono theater formats. The Radio Broadcast market was fading around 1950 with Televising looming & obsoleting AM Radio. RCA marketing was not yet interested in stereo, and the monaural LC-1 monitor was considered adequate for near field monitoring.

However in 1950, Dr. Olson attempted to improve the LC-1's narrow beam dispersion in the high frequencies caused by the 15 inch cone operating full bore up to a crossover of 1500 Hz Dr. Olson placed a small metal bow-Tye directly in front of the Two inch tweeter nested in the two inch voice coil of the 15 inch woofer cone to scatter the high frequency's out to wards the small multiple-bump inverted cones on the woofer cone. ,

This modification did improve the high frequency dispersion, however the high frequency scattering did damage the phase shift in this spectrum, which was not very serious as a mono speaker, but it did damage the stereo imaging in stereo monitoring. Ce La Vie.

Ultimately, RCA marketing supplied JBL Monitors to the TV & Radio Broadcasting markets for quite a while, and_ Ha, Ha_ RCA Camden employees qualified as JBL employees with all the JBL discount amenities.

cheers, herki the cat

Ian Mackenzie
04-05-2010, 02:24 AM
Not many people woud realise I used the T%# crossover topology for the high pass filter (in the previous attachement) :D.

Harryup
04-20-2010, 07:43 AM
I found this thread very interesting to read since I'm on the same kind of journey.
I started with JBL2450+StereoLab Tractrix, bellow JBL2227 and as low bass 2psc of the Paradigm Servo-15. Since I'm using BSS FDS-366T I have a lot of options for adjustments. Over time I got more than a bit annoyed about the fact that the system was so narrow in beaming, but well that the drawback of horns kind of was my beliefs. I have been using horns for a rather long period of time so I have been constantly upgrading and rather happy despite the beaming. But since I have used passive filters earlier built by the book and I have used active analog crossovers I have never had the opportunity to alter the delay and phase so easily.
My system was measuring rather flat using professional gear, I then came across the Swedish XTZ-room analyzer. Still measuring flat I found some more room nodes I treated both physically and with the PEQ in the BSS. But that little software also told me that the drivers was way apart in distance. I checked in the BSS and found that I had missed that the scale was 0.001 m instead of 0.01 m so I missed by a factor 10. I realigned according to the XTZ software and the beaming vanished. Most likely skills with passive crossovers will give the same results although I have not heard that so far from DIY project. I certainly does not have that skills.
So encourage I went from rather happy to extremely happy to curious. First I came across the TAD 1102's and started using them instead of the 2227 and got in that case a warmer and clearer sound.
So I became a bit more interested in TAD 4001 since I have heard them back in the beginning of 80's at a friends house. So I found 3 4001's and became way happier. Less treble shelving necessary and an overall clearer sound. In my search for a 3'rd 1102 for the up coming center I came a cross the TAD 2002. Did I need them, of course not. Did I buy them, Yes.
And with new 1" Stereo-Lab tractrix 700Hz horn they sounded even more extended and the music sounded more relaxed and even a bit slower sins it became even clearer. Happy, oh yes and my friends acknowledge that this is the best sound I have had so far. Up until about 4 weeks ago. I found a pair of the Yuichi 1" horns second handed.
I must say that the improvements over the tractrix is stunning. Better transient response, a bit darker, more chest tones in voices, less nasal although that was not a genuine problem before. Guess that of fairness the weight of the "plastic" horns suffers a bit in resonance aspects.
One drawback is that I need a bit shelving 6 dB from 6-7kHz and upwards but the overall sound is extremely smooth and clear.
Now I do need to arrange boxes for my 1102's and decide whether I'm going to use 1 or 2 of the 1102's per channel.
But I'm happier than ever before and I have been happy all the time since every step has been an improvement but I has not been possible to get updated advices since Sweden is a very small market and studio gear is not so common among home listeners.

best wishes
Harry

Ian Mackenzie
04-24-2010, 04:56 PM
Hi Harry,

Interesting post.

Its reasonable to assume not all tractrix horns are the same.The BSS FDS-366T will also add its own tonal signature.

Ian

Ian Mackenzie
06-14-2010, 07:46 PM
I actually got around to measuring this system and listening to it this weekend.

No firm conclusions yet as there is a lot more work and experiementation to be done yet.

Ian Mackenzie
08-25-2010, 06:01 AM
Well I actually got around to trials of the crossover tonight.

Every loudspeaker builder will tell you his system sound great.

I can tell you it sounds as good as it measures.

The crossover point on my most recent network is 650 hertz.

I derived this after carefully reviewing the natural low pass response of the horn in that I wanted to use the final acoustic slope to form a 4th order response with a 2nd order high pass electrical filter. After careul optimation the response though the crossover point is within +-1 db on axis of the horn. The woofer has an electrical 4th order filter.

You cannot sense the crossover point at all and that horn is absolutely glorious.

While obviously not a Cd horn there is no detectable horn sound in direct comparison to my reference ( JBL 4208) running a mono signal to both the reference and the test channel.

Not wanting to elaborate with too many subjective statements but the lack of power compression is immediately obvious compared to the reference system.

There is a sense of space, scale and richness of tonal texture overall that is difficult to convey in words. In all a very coherent presentation. With an increase in volume the natural decay of sound from within the instrument (such as acoustic guitar) entlightening.

The bass reponse appears well extended, very natural and is not over pro nounced but makes the room quiver on the right recordings.

The results of the project at this stage are very promising.

I will post more details over the weekend

Thank Clark for providing some really excellent recordings.

Ian Mackenzie
08-26-2010, 05:12 AM
Yes,

Here is the reason:

http://www.audioheritage.org/vbulletin/showthread.php?21738-An-E2-inspired-loudspeaker-Quick-but-not-dirty&p=234430&viewfull=1#post234430

While there ain't a JBL sticker on this driver it is like a 2012 but with mid bass characteristics. The 15M shares many of the 2012 features such as a full copper sleeve on the pole and de modulation rings and is underhung.

http://www.jblpro.com/pub/components/2020h.pdf

Pending how far things go I may eventually produce the design to order.

For this reason the network schematic will not be public domain.

I have invested $1000's in development tools and materials so please understand.

I will post response curves in the near future.

JeffW
08-26-2010, 09:00 PM
...that horn is absolutely glorious.



You still using the Emilar horn? Tad 4001? I've lost track, but it's fresh in your mind.

TIA.

Ian Mackenzie
09-03-2010, 03:37 PM
Apparently.

I should add I have since tweaked the Xover and its getting better in terms of overall balance.

While a two way system might seem simple enough getting the right balance overall is a delicate process of adjustment of extreme lows and highs aside from trying to get a smooth linear response.

I should point out I acquired a pair of Tad ET 703 super tweeters recently and will trial them when time permits. In comparison to the JBL 2405 (077) there is no comparision.

Ian Mackenzie
09-05-2010, 04:07 AM
Well I am still listening to these monoliths so they can't be half bad.

The problem seems to be finding a source good enough to judge how good they are.

I have some Blue Ray disks with True HD audio and they excel on that (Jeff Beck).

The measurements aren't everything and has been some experiementing and the capacitor (quality) in series in the network is critical to attaining the resolution and stage depth these horns are capable of.

The network is not that complex.

Ian Mackenzie
10-06-2010, 02:43 AM
This project is still work on progress

Impressed with the performance of the Tad 4001 the next phase in tne project will be to upgrade to cost no object drivers.


There is a possibility I will front load the woofer to provide consistant horn loadind and time alignment of the compression driver and woofer like the blue thunder project.

Ian Mackenzie
10-09-2010, 12:12 AM
There is a possibility I will front load the woofer to provide consistant horn loading and time alignment of the compression driver and woofer like the blue thunder project.

For those interested this is the link to the post of the Blue Thunder


http://www.audioheritage.org/vbulletin/showthread.php?21738-An-E2-inspired-loudspeaker-Quick-but-not-dirty&p=225096&viewfull=1#post225096

I have kind of come back to this design after auditioning the direct radiator version I built and reading articles and reviews of similar correctly front loaded system. I also heard some front loaded systems in Japan and in CA when I visited Steve Schell in 2007.

They have a certain quality that that creates a sense of realism that is at best very expensvie to create even with the finest drivers like the JBL 1501.

In terms of drivers I plan to use the AE 15M woofer to start with and a Tad 4003 with the option of the ET 703 device. The JBL E145 would be an interesting alternative or the Great Plains 416. If the result prove encouraging I may look at other woofers. The Focal woofer used in the project is NLA.

As discussed in the Blue Thunder article there are also some interesting practical benefit. Basically the woofer does not have to work as hard it just seems to work.

I have not previously used the 4003 but apparently getting it to blend with some woofers has proven a chore. The AE 15M appears to have a dynamic quality (possibly due to the sophisticated motor adn low mass cone) and I expect the front loading from 120 - 600 hertz will will benefit that aspect of the performance.

This all might have seemed like a long winded exercise but half the fun is thinking about it, the other half is actually doing it and spending the money. As an thread there is a heap of info here and anyone can pic and choose snippets of data.

pos
10-09-2010, 01:03 AM
Hi Ian


They have a certain quality that that creates a sense of realism that is at best very expensvie to create even with the finest drivers like the JBL 1501.

What about a midrange cone driver like a TM1201 to get some more dynamic capacity in the 200-600Hz range?
I think you kept your 2245H's, that would be an intersting combo.

Ian Mackenzie
10-09-2010, 05:53 AM
Hi Pos,

Yes that is an option but l am trying to avoid another xover point.

Have you any experience with that driver?

pos
10-09-2010, 06:51 AM
Have you any experience with that driver?
Well, I have a pair waiting for some serious tests. I need to build test boxes!
I plan to use them toghether with a pair of 2245 (~200Hz) or ME150H (a bit higher), and H9800 (~1khz) or PT-F95 (~1.4khz).

JeffW
10-09-2010, 06:45 PM
This project is still work on progress

Impressed with the performance of the Tad 4001 the next phase in tne project will be to upgrade to cost no object drivers.


There is a possibility I will front load the woofer to provide consistant horn loadind and time alignment of the compression driver and woofer like the blue thunder project.

What horn are you going with now that the Emilars are up for sale?

Ian Mackenzie
10-10-2010, 04:12 AM
What horn are you going with now that the Emilars are up for sale?
Tad

Ian Mackenzie
10-14-2010, 04:59 AM
http://www.hifidiprinzio.it/files/2009/08/200908271249285.pdf

JeffW
10-14-2010, 06:28 AM
Gotta love Sid Haig.

4313B
10-14-2010, 07:11 AM
Wow! After looking that over I just realized that I'm really not all that into the whole "audio" thing. :rotfl:

I guess my rather conventional, E2-inspired JBL loudspeakers will just have to do.

Ian Mackenzie
10-14-2010, 01:00 PM
.
Wow! After looking that over I just realized that I'm really not all that into the whole "audio" thing. :rotfl:

I guess my rather conventional, E2-inspired JBL loudspeakers will just have to do.

Well looking Greg.s most successful designs they been anything but conventional.

My interpretation is this field belongs to esentric self obsessed artisans.

Ian Mackenzie
01-20-2013, 10:55 PM
Still a work in progress.

I will post a pic in the near future.

It will go in the living room that spans 4 x 8 metres overall.

allen mueller
01-27-2013, 06:12 AM
I'm excited to see some updates. This thread is one of my favorites and the amount of information you gathered is much appreciated. Thanks for your hard work.

Al

Ian Mackenzie
01-27-2013, 08:33 PM
Hi Allen,

Yes it uesful as its eary to forget a lot of this stuff over time.

I am in Bali at the moment but a few words are in order.

Like all diy projects it can take a while and sometimes you end up with a pile of drivers that need a home!

So I need to get this sorted out.

After you build a new home and everything is beautiful someone like Dan Ashcroft is in high demand to make something that looks good on paper fit the decor of the home.

The living room is vast and open plan so a system with some controlled directivity might be useful.

Coming up with something that will work is mean feat and I can now see what JBL crapple with in coming up with suitable systems.

There are several approaches but the ancher (for now ) is available components , the Tad 4003, Tad 703, AE 15M, Emilar horn and possibly a Tad horn.

I also have a pair Century Gold 1200H 12 inch woofers which will be the fall back plan if the above AE15M woofer box does not work out..its needs to be 7 cu ft 3. The 1200H and a helper sub would no doubt be more WAF friendly but not nearly as much fun as a large format system.

Another option at a pinch is I could turn out a 4344 for the living area and use the project system for the home theatre.(at least I know it works

As a reality check I plan to first trial existing boxes in the living room to assess the bass response.

This will be the get-go on progressing with the AE15M woofers. They are much like the Altec 416. A big box is unfortunately a must

If this looks promising I propose to look at a direct radiator (woofer ) system and compare with a Tractrix front loaded system.

If not I will post WTB a pair of LE14's

I was reading Mr Widgets long thread on curves mdf panels and that looks scary.

So the cosmetics will be added after the working systems is prepared. ie a curved front facia and sides as require.

A bit like trowling on makeup but there you are.

Ian Mackenzie
02-05-2013, 07:32 AM
I have conducted an inital trial.

Using my reference monitors manufactured by ex Linn designer Rod Crawford some insights into the new listening environment were obtained.

The idea behind this approach is that as a known base line I can gauge what the room is doing as this is as much an unknown as the new proposed system

The overall presentation was spacious, open and punchy with surprising sound stage depth.

There are not really obvious room modes room modes but the anticipated room gain below 100 hz was not overly apparent.

Some rear field effect is noticable towards the rear of the room some 25 feet back


The step will be to trial the significantly larger project boxes with the AE15M woofers and see how they fair.

Ian Mackenzie
03-16-2014, 12:02 PM
I recently restored the diy 4345 in the listening space, just need the correct JBL blue paint and I will bark them up. Unfortunately they are a bit too big.

The earlier post on décor still applies......

My latest idea is a wedge shaped box not unlike a pa monitor with a curved front and sides.

Currently exploring horn and wave guide options

Ian Mackenzie
03-22-2014, 07:01 PM
As far as box style is concerned i really like the L200 low boy classic design not withstand its dimensions were acoutically sub optimal.

While mostly listen in the setted position i am mindful of stand up listening so i have been pre planning with a string line to obtain the best compromise in terns of horn mouth height and baffle angle.

The ear height seated is 95cm. So i have gauged the tlit angle for centre horn height of 85cm. This gives a modest but effective lift in the horns. 30-40 degree vertical window in the far field .

The overall enclosure height will around. 95cm. This was derived emperically after accounting for hornheight driver spacing. The L200 was about 80cm in height dimension . This would have placed the botton of the woofer only 15cm off the floor and possible caused booming ro mask the midrange and a suck out in midrange due to floor bounce cancellation.

I have not yet decided if i will opt for straight side walls or truncated with a narrow rear wall . The overall width is about 60 cm. The volume of the side wall would all provsion for front horn loading of the woofer anf would break up the box modes with staight walls.

The plan would be a tractric horn or Altec from 120 hz to 600 hz.

The construction would be more challenging but woulf provide time alignment with the Tad 400 driver and the woofe.

Horn loadin the woofer also sorts out the difficult match up of horn and wooder coverage angles and defines the direct sound patten.

On reading Tom Hidley's'early studio design ideas in a aper by Philip Newell the choices are simple in terms of how to manage the amount of reflected sound wih either room treatment or controlled coverage. I dont want to intall deliberate room treatments
So control of coverage angle is useful where the system is targettinf more of a near field listening pattern.

If you look at the attachment Blue Thunder that is the idea.

Ian Mackenzie
11-11-2015, 01:23 PM
It's been a while since my last post and like other members projects....sometimes life gets in the way.

Over the past 6months l have been evaluating system configuration that would perform appropriately but also blend cosmetically in the listening room.

This is a very challenging quest and is a labour of love no doubt for the industrial design team at JBL.

I have looked at Tad horn clones, SEOS wave guides.and while these horns have some good attributes the wide of the horn make the enclosure look too much like a big box.

So, l have tacked the box dimension on two fronts, sourcing of a different driver and a new norm/waveguide.

The selection has come down to the JBL 2216 Neo driver that requires 60 litres less box volume than the AE15M @130 litres and the AH700 conical horn (no longer in production) that has a 40cm diameter and is some 20cm deep.

The room classic styling with leather furnishings and oak floor lend to box design not unlike the Altec Iconic but scaled for the 130 litre enclosure size.

The horn will be mounted on an adjustable pivot to enable critical adjustment of the driver angle and displacement relative to the woofer.

Some images below of raw horn images and FR curves.

It's not a text book perfect world but with some careful eq of the off axis power response excellent subjective performance rivalling most two way systems can be obtained.

The actual test curves will be published soon enough.

Ian Mackenzie
01-07-2016, 11:01 PM
Okay,

Over the holidays l have been able to finalise the prototype crossover.

The woofer is a piece of cake and there is box diffraction issue in the test box that l will ignore for now.

The conical horn took some understanding. It is true CD and when equalised extends to about 18 Khetz.

However the power response at 0, 5, 10, 15, 20 and 25 degrees varies somewhat and is hot in the 2-3 k hertz area on axis until about 15degrees off axis.

After a lengthy read of all the Harman papers by Floyd l reasoned the controlled directivity and off axis power response was more important than the 0-10 on axis response from the horn. Floyd says only equalise resonances, not diffraction and shoot for as smooth as possible response from 700-7000 hertz.

So the next step was to find the best fit for the off axis power response of the horn into the listening room.

Reviewing the averaged equalised power response 15 degrees off axis was the best overall compromise.

Based on this decision l set about to design for a flat response at 15 degrees off axis to the centre axis of the horn.

This will require the listening height to be 320 mm below the centre axis in the vertical plane of the horn at a distance of 2 metres. The seating is a bit more like 3 metres but the variation in the angle along this long axis is not significant.

I ended up with very little passive equalisation of the 2-3 khertz hump and rather than fight the horn on axis response with EQ l am using the off axis response to the advantage of the listening window.

Physically the driver layout will have the horn elevated above the seated listening height with the on axis response going over the head of the listener into the far field of the room.

I figure the far field some 5-8 metres back will have so much reflected sound the on axis hump at 2-3 khertz will not be an issue.

There were 3 areas of passive equalisation l decided to focus on in the end :2.5 k hertz, 4.5 khertz and 9 k hertz. This was to level the response overall.

I used a series LCR circuit to equalise the horn response overall and borrowed the topology from some of JBL recent designs. The low value of the Fixed LPad shunt resister provides low voltage drive ripple at the low end of the passband (unlike the 4430/4435 networks).

I will incorporate a variable L pad into the LCR to provide an HF adjustment. An LPad will also be inserted in the equalisation for fine tuning presence of the 2.5 Khetz region.

Structurally the horn will elevated some 320 mm above the listening height and the horn tlitled at 5 degrees back.

The bottom of the horn will be some 100 mm proud of the top surface for cosmetic reasons and to minimise enclosure diffraction.

The horn and woofer centre is 500 mm apart.

The bass reflex enclosure is conventional and 130 litres in volume and 102 cm in height.

The bass response can be boosted per DB Keele's alignment to improve low end extension and displacement limited output.

The overall approach of a smooth off axis response may be against conventional wisdom but if it's assumed the listener will be at about 2-3 meters from the loudspeaker the above approach will yield the best power response tracking on axis to the listening window per the Harman paper.

The curves are self explanatory but the crossover requires some description.

The crossover is an hybrid individual active and passive cascaded 3 db networks that when combined are LR12 CB network on the high pass section The woofer is active 12 db LR.

I spent a lot of time getting the phase in the crossover right and with careful adjustment the notch is some 30 db below the reference level.

The lateral displacement of the driver acoustic centres, the driver phase response and crossover phase response all impact on the phase optimisation in the crossover region.

I was able to optimise the phase null at the crossover point using LEAP.

The system could be described as phase compensated in the crossover design.

Fine adjustment of the crossover point spreads of the woofer and horn and the lateral displacement can be evaluated with LEAP.

Woofer acoustic voice coil= 115mm
Horn acoustic voice coil = 280mm
(Referenced the front baffle)

The distance from the horn mouth flange to the driver vc is about 275mm so the horn assembly can be conveniently located above the woofer enclosure.

As a result the summation is in fact dead flat at 0 degrees (320 mm below the horn) through the crossover region.

I also spent a lot of time investigating the vertical polar nulls.

The nulls above and below the central lobe are normal (in the crossover region).

I don't think this aspect of the design has precedence over other aspects including flat response and a reasonable match of the woofer and horn polar response at the crossover point. The horn polar response is 60 degrees and unloads at the lower end. The crossover point is 800 hertz. This will be evaluated with pink noise once the system is assembled.

After a while l was able to come up with a polar response lobe that favours the bottom half of the horn axis through the crossover region. When the driver phase is reversed the true frontal lobe is focused on axis.

Of course it remains to be seen what happens in practise but l am confident that the LEAP sims and LMS ground plane measurement are good.

The drivers are Tad4003! AE 15M (JBL 2216 to replace the AE15M)

From top to bottom

Vertical lobe in phase
Vertical lobe out of phase
On axis equalised response (at listening position 2-3 metres)
Network schematic
Voltage drives

Ian Mackenzie
01-07-2016, 11:18 PM
These curves are 5 db per division. I found 5 DB divisions useful for ironing out the bumps but l prefer 10 divisions for looking at the flatness and levelling of the overall response.


I don't think the notch at 2k hertz is a major issue, it's not the driver but the crossover artefact. Much steeper slopes would be required to minimise this.

I have combined the driver guide curves and the system curves below to illustrate the deviation in the power response.

All ground plane measurements were done in my drive way.

From my recollection using the 4430 crossover it had a shelf L pad around 2 Khetz and the effect is to warm brass instruments. I generally had the LPad up full do its not an unpleasant effect. I may create a adjustment for this once the system is up and going.

I have not listened to the most recent iteration of the crossover but using a simplified all passive crossover it was quite promising. Low level details are early discernible and you could really hear the recording environment.

These images are all via the I Pad Mini camera as l did not have access to upload via the desktop server.