built myself a 3-way with 2235 / 2123 / 2435 / pt-h1010

[frank23]

hi,

I built myself a 3-way with 2235 / 2123 / 2435 / pt-h1010 today.

Having collected these drivers over the years and having used them (except the 2123) on and off in different 2-way settings, I decided I wanted to know what a 3-way with the 2123 sounded like.

So I designed some cabinets so that I could also use the cabinets separately (should I want that), got me some wood and started glueing, cutting, drilling and building. It is now 23.00 here, and I have one channel playing using the M552 as a single channel 3-way active crossover.

The 2123 probably has to loosen up some as they have never been used. Tomorrow I'll probably tidy up the back of the cabinet which is now fastened with wood clamps...

Now I have to find myself another M552 and build the other channel too!

I hope to have a measurement microphone and behringer ultra deq 2496 soon to see what the output measures like. For now it sounds ok.

http://i200.photobucket.com/albums/aa253/frankvcp/DSC03770.jpg

http://i200.photobucket.com/albums/aa253/frankvcp/DSC03776.jpg

http://i200.photobucket.com/albums/aa253/frankvcp/DSC03782.jpg

http://i200.photobucket.com/albums/aa253/frankvcp/DSC03785.jpg

Regards, Frank

[grumpy]

I would think this nice group of parts could be made to sound quite nice :)
Especially not needing to push the horn/driver so low (as a two-way would).

When you have time, perhaps you could post crossover settings and any
EQ (active or passive) that you found appropriate/listenable. Often the M553's
are nearly the same price as M552's, so you might keep an open view
regarding what is available.

A humble suggestion, if you already have a portable computer:
skip the ultra deq and get a mic-pre/usb converter. Or, if you were
planning on using the EQ facility of the unit, add the mic-pre/usb
later, as you will get far more visibility into what's going on with
an software analysis package than the RTA function of the deq box.

[Robh3606]

Hello Frank

Curious to see how you like the combination of drivers.

Rob:)

[demon]

very interesting...3way with the 10" mid, i bet it kills!!
be careful.. ;) and keep us posted.

cheers,
mikey

[frank23]

I would think this nice group of parts could be made to sound quite nice :)
Especially not needing to push the horn/driver so low (as a two-way would).

When you have time, perhaps you could post crossover settings and any
EQ (active or passive) that you found appropriate/listenable. Often the M553's
are nearly the same price as M552's, so you might keep an open view
regarding what is available.

A humble suggestion, if you already have a portable computer:
skip the ultra deq and get a mic-pre/usb converter. Or, if you were
planning on using the EQ facility of the unit, add the mic-pre/usb
later, as you will get far more visibility into what's going on with
an software analysis package than the RTA function of the deq box.

I have set the crossover points at 150Hz and 3000Hz now. Also the m552 has the CC EQ configured for the high output.

What would be a better combination sound wise, buy another m552 and have dual mono, or buy one m553 and use one stereo (and have my current m552 free for other projects).

Do you have suggestions for the usb mic / software combination? I work on a mac, but can also use an XP laptop.

[pos]

150Hz is a bit low for the 2123, you will need some eq if you want to cross that low.
3000Hz is also a bit to high: the 2123 will beam too much at this frequency. The best is to choose a frequency at which the 2123 and the waveguide have the same beamwidth (ie 100deg) :
http://audioheritage.org/vbulletin/showthread.php?t=24621#5

Also the CD compensation build into the m552 is good enough for general purpose PA, but it is certainely not properly matched to this waveguide.

If I were you I would build Rob network (exact same component) for the top, and try the m552 to biamp with the 2235 coming somewhere between 300 and 400Hz

[frank23]

150Hz is a bit low for the 2123, you will need some eq if you want to cross that low.
3000Hz is also a bit to high: the 2123 will beam too much at this frequency. The best is to choose a frequency at which the 2123 and the waveguide have the same beamwidth (ie 100deg) :
http://audioheritage.org/vbulletin/showthread.php?t=24621#5

Also the CD compensation build into the m552 is good enough for general purpose PA, but it is certainely not properly matched to this waveguide.

If I were you I would build Rob network (exact same component) for the top, and try the m552 to biamp with the 2235 coming somewhere between 300 and 400Hz

ok, I'll try some other crossover frequencies and see what the result is, luckily it only takes the turn of a knob, ready in a few seconds

but since my goal is to have one driver cover the whole mid without a crossover in critical areas, crossing over at 1500Hz will be too low for that goal, but I'll experiment

I know the CD compensation is not optimal, I hope to get an RTA measurement device soon and see if it tells me the same as my ears

[grumpy]

Mac software... I've been pleased with FuzzMeasure. Their web site has
some usb/pre and mic recommendations.

I concur with 'POS', in that ultimately, you may want to consider a passive
network for the mid/high transition and to EQ the horn/driver.

M552 vs M553? seemed like if you could find an M553 at the same or similar
price, it would be a win-win.

[Russellc]

hi,

I built myself a 3-way with 2235 / 2123 / 2435 / pt-h1010 today.

Having collected these drivers over the years and having used them (except the 2123) on and off in different 2-way settings, I decided I wanted to know what a 3-way with the 2123 sounded like.

So I designed some cabinets so that I could also use the cabinets separately (should I want that), got me some wood and started glueing, cutting, drilling and building. It is now 23.00 here, and I have one channel playing using the M552 as a single channel 3-way active crossover.

The 2123 probably has to loosen up some as they have never been used. Tomorrow I'll probably tidy up the back of the cabinet which is now fastened with wood clamps...

Now I have to find myself another M552 and build the other channel too!

I hope to have a measurement microphone and behringer ultra deq 2496 soon to see what the output measures like. For now it sounds ok.

http://i200.photobucket.com/albums/aa253/frankvcp/DSC03770.jpg

http://i200.photobucket.com/albums/aa253/frankvcp/DSC03776.jpg

http://i200.photobucket.com/albums/aa253/frankvcp/DSC03782.jpg

http://i200.photobucket.com/albums/aa253/frankvcp/DSC03785.jpg

Regards, Frank


Nice, I would like to try the same type of thing. Also have the 4507 box and NOS 2123H drivers. will use 2425H and 2344a and 4430 HF comp however.

Russellc

[4343]

Nice, I would like to try the same type of thing. Also have the 4507 box and NOS 2123H drivers. will use 2425H and 2344a and 4430 HF comp however.

Russellc

That's almost the route I'm taking, except the box so far is designed to house everything. Might change that before I put it together after seeing the two-piece design. I'm working on a sub for one of my three 2235H's now, so maybe I'll try it with the 2223H and 2344 in a separate cab before I commit to the all-in-one box...

[Russellc]

150Hz is a bit low for the 2123, you will need some eq if you want to cross that low.
3000Hz is also a bit to high: the 2123 will beam too much at this frequency. The best is to choose a frequency at which the 2123 and the waveguide have the same beamwidth (ie 100deg) :
http://audioheritage.org/vbulletin/showthread.php?t=24621#5

Also the CD compensation build into the m552 is good enough for general purpose PA, but it is certainely not properly matched to this waveguide.

If I were you I would build Rob network (exact same component) for the top, and try the m552 to biamp with the 2235 coming somewhere between 300 and 400Hz

What is the " Rob net work" for these components?

Thanks inadvance, Russellc

[Russellc]

That's almost the route I'm taking, except the box so far is designed to house everything. Might change that before I put it together after seeing the two-piece design. I'm working on a sub for one of my three 2235H's now, so maybe I'll try it with the 2223H and 2344 in a separate cab before I commit to the all-in-one box...

I have the 4507 box for 2235H, so I'm thinking of a 2 piece design as well.
That knock down parts express box may be perfect for this! (Except for the 12 inch hole. there's plenty of room to add another front baffle over it with a hole for the 10 incher!)

russellc

[Zilch]

I believe we have been here recently:

http://www.audioheritage.org/vbulletin/showthread.php?p=249603#post249603

[pos]

What is the " Rob net work" for these components?

Thanks inadvance, Russellc
It is the network Robh3606 (http://audioheritage.org/vbulletin/member.php?u=23) is using in his similar design.
I believe he posted it somewhere on these forums.

[pos]

no, I though you had posted your 2123+2435/PT-H1010 network somewhere.

[Robh3606]

Hello pos

Forgot he was doing an active a M552. He needs to workout where he will be crossing over and if the on board 2360/2380 horn compensation works for him or not. Any of the compensation networks I have up are all tailored to run with a matched driver pairs. His drivers may be a bit different than mine so it will work but may need to be tweeked a bit.

Rob:)

[Zilch]

C'mon, guyz, NAIL this!

M552 CC is the wrong comp; we know it.

I ran a dozen 2435HPLs on PT-H1010 using the "Gauntlet" comp filter and M552 @ 1 kHz:

http://audioheritage.org/vbulletin/showthread.php?p=147389#post147389

Yes, I still have all of them and more, and can to redo it. How many is required? 20? 50?

I have provided the schematic, parts list, board layout, and pics of the charge-coupled finished goods; they cost all of $50 apiece, including the expensive 9V lithium battery and holder.

Build it, tweak it, make it work. Rob knows how to adjust the attenuation.

Why does this have to be shrouded in arcane mystique here? :banghead:

[Robh3606]

Why does this have to be shrouded in arcane mystique here? :banghead:

Where is the arcane mystique?? How to do this is all over these forums.

http://www.audioheritage.org/vbulletin/showthread.php?t=23343&page=2

Rob:)

[Zilch]

Where is the arcane mystique?? How to do this is all over these forums.

http://www.audioheritage.org/vbulletin/showthread.php?t=23343&page=2I don't know. It seems like every time somebody wants to do this, they start over from scratch.

Frank was an active participant in that thread. Why is he kerfutzing with M552 CC comp?

I'm not being unfriendly to or critical of him in that. The question is, "Where is the disconnect?" He could be using way more optimum comp for ~$20 in parts:

http://audioheritage.org/vbulletin/attachment.php?attachmentid=22352&stc=1&d=1170101554

[Robh3606]

Hello Zilch

History repeating itself. Look through the first 2 pages. We all have to try things for ourselves. Human nature?


http://www.audioheritage.org/vbulletin/showthread.php?t=9745&highlight=Quick+Dirty+4430

Rob:)

[Mr. Widget]

Why is he kerfutzing with M552 CC comp?I get the M552... an older active crossover sold by JBL. I realize it offered convenient though generalized compensation alignments for JBL's bi-radial constant directivity horns... but why is it called "CC comp"?

I realize this is a bit tangential, but you keep posting it and I have no idea what it means and feel a bit stumped.

OK, just figured it out... Constant Coverage. Is that term synonymous with constant directivity? To my recollection CD "constant directivity" is the commonly used term... that said, using the CD abbreviation can be quite confusing as it can also mean compression driver or compact disc. CC on the other hand typically means charge coupled to me... all of these abbreviations and short cuts drive me nuts...

"Oh, so that is what did it?" :D


Widget

[Zilch]

For 523x crossovers, JBL offered two series of plug-in cards with equalization, Flat Front Biradial EQ for Series 80 horns, FFBREQ, and Constant Coverage Biradial EQ for Series 60 horns, CCBREQ. These each have different high-frequency compensation contours. In M552, it's just Series 80 vs. 60 via different switch settings. In detail, those are different from their earlier iterations, as well, as are the built-in generic "CD Boost" curves of crossovers from different manufacturers.

Bottom line: HF comp for different driver/horn/waveguide combinations is unique to each, and best implemented with precision using an engineered passive or parametric filter. I recently illustrated this by measuring the full spectrum of six different PT waveguides on the same driver in another thread here.

Frankly, I have no clue what "Constant Coverage" means, but JBL apparently considered it to be a distinguishing feature somewhere along the line of development of these technologies. I would not be surprised to see "™" appearing after it in the contemporaneous literature.... :blink:

[Mr. Widget]

Personally I'd like to see more of this:
Frankly, I have no clue what "Constant Coverage" means, but JBL apparently... and less of this:
C'mon, guyz, NAIL this!

M552 CC is the wrong comp; we know it.All of the shorthand makes it seem that you expect the reader to have read every post you and others have made... that simply isn't usually the case.

As for your point about generic compensation filters built into these various pieces, I think we are all in agreement that except for cases where there is a DSP chip that has been programed for a specific finished product loudspeaker model, they are never meant to be "the answer". They just point you in the generally correct direction... they expect you to either live with that state of affairs or finish the job actively or passively as the system requires.

We all know that designing a filter for a specific horn, or even horn and driver is only part of the design... the low pass portion also affects the response and must also be taken into account. By definition, no generic filter will ever be ideal.

I think I've drifted off topic again. :o:


Widget

[4313B]

We all know that designing a filter for a specific horn, or even horn and driver is only part of the design... the low pass portion also affects the response and must also be taken into account.And, as you already know, the enclosure and baffle arrangement, or lack of one, also matters.

[frank23]

I don't know. It seems like every time somebody wants to do this, they start over from scratch.

Frank was an active participant in that thread. Why is he kerfutzing with M552 CC comp?

I'm not being unfriendly to or critical of him in that. The question is, "Where is the disconnect?" He could be using way more optimum comp for ~$20 in parts:

http://audioheritage.org/vbulletin/attachment.php?attachmentid=22352&stc=1&d=1170101554

:-)

Frankly, it is just lack of time. With 3 young children and a number of other hobbies there is only a few hours a week for tinkering. With the M552 I can easily fool around a little after the children have gone to bed. Just turn the knobs and compare.

Before I delve into building a real compensation etc. I want to have the feeling the drivers and horns have a basic quality in them that makes it worthwhile. I haven't found this with the 2435 / PT-H1010 yet I must say, but maybe it is just me. My 2420/2344 combination always sounds nicer.

Maybe fooling around with the M552 doesn't give the 2435 combo a fair chance. Tonight I have lifted the 2123/2435 two stairs up to a room with better acoustics, see how it behaves there (without the 2235 as that is too heavy).

I am going to have me a Behringer Ultra deq 2496 though!

And btw, I am one of those people that HAS read all of the threads about this. There is just so much info in there...

[pos]

buy a DCX2496 instead of a DEQ2496, so you will be able to do crossovers AND compensation (EQs) with the same unit.

[Zilch]

buy a DCX2496 instead of a DEQ2496, so you will be able to do crossovers AND compensation (EQs) with the same unit.Yes, of course, but nothing's gonna happen without measurement capability, and DEQ provides that.

Hit "AutoEQ," and it'll also tell what needs to be done.

With the requisite for precision design? Nope, but good enough to enable the listening comparisions desired here.... :yes:

[Ian Mackenzie]

I would start by working out where the power response of the 2123H falls off then you have a starting point. The power response is quite important for home use othrwise it will sound horrible. Aiming for flat on axis response alone is not really going for make a great sounding system for home use.

That is why you like the 2344. I have used the 2344 with a 10 inch driver (2122H) and it works very nicely.

Typically the maximum crossover is 1200-1500 hz for a 10 inch driver.(otherwise it will honk) like some of those Altec VOT's.

Then look at the specs for the wave guide. Do not use the wave guide lower than the designed minimum crossover point ...distortion will sky rocket and it will sound horrible. The power response of the wave guides also falls aprt at low frequencies and the response gets rough. Most of these wave guides are not intended for use below 1200 hertz. Ideally the LF power response of the waveguide should match the 2123H at the required crossover point.

The next step is the design a low pass filter for the 2123 that equalizes its rising response for the designated crossover point. (This is a ball breaker without suitable test equipment).

Do the same for the wave guide and incorporate passive EQ.(ball breaker no2).

Using a a stock universal active filter is shooting in the dark particularly if its for home use. The older vintage horns and drivers where much more user friendly for stock active filters (see Drew's clues).

You might be better of getting someone to work out the crossover. It will save a lot of time and frustration.

[frank23]

hmm, I have only come upon this thread now:

http://www.audioheritage.org/vbulletin/showthread.php?t=24291&page=6

great info! there is just too much info on this forum!

[Zilch]

And I just ran across this post:

http://www.audioheritage.org/vbulletin/showthread.php?p=134899#post134899

[Robh3606]

Just adding a bit to one of Ian points. If you look at the polars as far as matching the directivity at crossover you have a narrow window. Above 2K and things get a bit dicey. The driver starts to beam so above that you have a rather abrupt change in DI compared to the waveguide if you decide to crossover in the 2-3K range.

Rob:)

[grumpy]

Hi Rob,

Is this a modeled plot, based on parameters you've input for a 2123H
(and baffle or enclosure), or pre-canned actual measurements that come with Leap, or ???

[Robh3606]

Hello Grumpy

That is using the preloaded model in LEAP. It predicts the rising response as well. From experience using LEAP I would consider any modeling done by it to be fairly accurate. That's with an infinite baffle mount. You can change the modeling to go full anecholic or in room. With in room you can adjust volume and spacing inside the room as well 1/2, 1/4 and 1/8 space.

Rob:)

[Russellc]

It is the network Robh3606 (http://audioheritage.org/vbulletin/member.php?u=23) is using in his similar design.
I believe he posted it somewhere on these forums.

Sorry, I wasnt clear:D I was looking for the circuit itself!

Still digg'in for it........I know 2123H must be handled carefully and figured this would be a good way.

The part of this thread that's got me is how the 2123H is treated.....I want this part right, I intend on either 2344A or some other waveguide/CD driver on top.....I figured Rob's would be the best way!
Russellc

[frank23]

I am still working on this project, slowly...

I re-mounted the waveguide for the upright position and tried the 2123 / 2435 again upright on top of the 2235 instead of lying down "on its side". I find this sounds better.

And I have sourced a 2nd hand M553 that I will pick up this weekend. And I ordered the Behringer UltraCurve DEQ2496 / ECM8000 mic with mic stand and cable to make some measurements and try eq-settings.

Now, I'll just have to build me the left cabinet, buy another few meters of speakercable, wait for the equipment to arrive, hook it all up with my 3 class-A musical fidelity amps and I'll have myself an incredibly complicated, power eating full active, digital-eq-ed, 3-way system!

For vertical alignment reasons, I might want to turn the 2235 cabinet on its side so the 2123 / 2435 sits a little lower. What do you think, the 2235 center is now 49cm above the floor and when on the side, this would be 27cm. It would make it more vulnerable to kids I guess, and there'd be more floor reflections, but the bass would probably also be stronger as there is more acoustic floor coupling.

[Robh3606]

Hello Frank

Since you are going to be using 24db L/R filters you may want to take a look at this Rane Tech Note

http://www.rane.com/note160.html

Your set-up is very similar to mine. Depending on the Voice Coil off set you may want to add a shim plate under the PTH1010 to get the alignment a little closer. I don't use one but it's an idea I have always played with. That aims your nulls but it may not be an issue for you as you are. I have another set-up using the 112A as a midrange and the step response in really good on the horns axis. The offset there is 1.45 inches between top plates 11 inches vertical.

A vertical stack would be the way to go. That way the nulls don't end up off to the side in a listening position if you don't listen on axis. As far as the 2235 spacing you can always put it back if it gets boomy.

Rob:)

[Robh3606]

Hello Russel

I have ran both the 2344 and the PTH1010 with the 2123 in an active set-up. I don't have a passive solution network worked out for it. The only passive componenets were the compensation networks used on the horn/waveguides. I don't have a schematic posted for those either. Pre LEAP so it was all done using an RTA/CLIO.

Rob:)

[frank23]

Hi Rob,

Would you know of a way to measure the step response without clio etc?

I have been looking for a impulse / step wav file to play on my cd-player and then measure the speaker output with audacity, but I haven't been able to find it. Is there another way? Maybe switch on a 1.5V battery on the amp input, that would sure be a step, just kidding, it would probably be blocked by the input capacitor :-)

From looking at it, it seemed that the acoustic centers for the 2123 and pt-h/2435 would be fairly aligned, how big do you think the difference is, 1cm max?

Frank

[Robh3606]

Would you know of a way to measure the step response without clio etc?


There is other software out there but I don't know if they will let you process a measurement in demo mode or if there is freeware or a trial set out there. They were playing with software over on DIY that a guy wrote and introduced there. I think its freeware might want to look for it.


From looking at it, it seemed that the acoustic centers for the 2123 and pt-h/2435 would be fairly aligned, how big do you think the difference is, 1cm max?


Well the rub is you can't tell by looking you have to actually measure to determine where the real acoustic center is. I used the line up the VC method when I did my 112A 2435/PTH1010 set-up. It's a passive crossover between the 112 and the PTH and biamped on the bottom. My alignment was more off physically than the 1 cm. If you look at the step response it look fine from what I did. I don't think you will have a problem with the 1 cm but I have never tried to measure what the real offset is.

Rob:)

[pos]

I don't understand why the voice coil is allways refered as being the acoustic center. The cone (or dia) is moving at exactly the same time as the VC, and that is what actually produce the sound, so this is what has to be considered the center (geometrically at least).

[4313B]

You might want to check out Mark's work here:

http://www.aes.org/e-lib/browse.cfm?elib=8194

http://www.aes.org/e-lib/browse.cfm?elib=8424

If not, just move the horn forward or backward until the sum at crossover point looks best.

[frank23]

Well, after days and days of building, the speakers are about finished. All that's needed are a few input panels for the rear. The amount of time involved has been far greater than I expected, but it turned out that even with an active system, you cannot ignore things like panel and cabinet resonances. So while the cabinets look about the same as in the first pics, they have been built to a much higher standard than before. Before they where just "driver placeholders" whereas they are now cabinets, braced and damped.

http://i200.photobucket.com/albums/aa253/frankvcp/DSC03948.jpg

http://i200.photobucket.com/albums/aa253/frankvcp/DSC03950.jpg

http://i200.photobucket.com/albums/aa253/frankvcp/DSC03953.jpg

In the proces, I put the 4507 cabinet on its side to reduce the height of the system. The compression driver is now slightly above ear listening height, the total system being 114cm high. It doesn't look too big, I think people from outside of this forum seeing these pics will think "I can accommodate that", but it remains massive with the 15" and 10" setup.

Listening now, I think I have to analyse and retune the parametric EQ on the behringer that I use, it sounds slightly harsher now than when the 4507 were standing upright. The m553 crossover points are set at 160Hz and 1400Hz (taking the polar graph above into account).

Linkwitz has written very interesting things about this: http://www.linkwitzlab.com/frontiers_5.htm

This is one of the pics on the Linkwitz page, I just put it here to make you go there and read it :-)

http://www.linkwitzlab.com/images/graphics/scan0015c.jpg

[frank23]

So, how does it sound?

That was the question for me too. I had all the components and decided that I'd either had to sell them or try them out. I need to do a lot more critical listening, but for now I have to say that the system sounds very, very impressive. Dynamically it is on a different level than I am used to, it is kind of strange to listen to sometimes, but you know it is right when you hear it.

Luckily it can still do "small", I am now listening to the Oscar Peterson trio in a 1957 recording and this is about as small and intimate as it is on my other passive 1st order system. For me timing is very important and I was afraid that the EQ-ed multi amplifier / multi driver system would not turn out to be good in this area, but all seems fine.

And as for scale, large orchestral work is just "large" with a big L and a lot of low frequency extension.

Katie Melua also sounds ok, apart from the sssses which are always a problem on her piece by piece album and the music which is problem by itself. But the sound image is fine, a bit up front maybe but very powerfull.

I think I'll be hooked most on the low frequency extension and the clean dynamics of this system. What remains though is to try out different decoupling capacitors and maybe the 2420 / 2344 combination instead of the 2435 / PT-H1010. And what remains is trying it out a bit louder when the rest of the family and the neighbours are away...

[frank23]

after about two weeks of critical listening, the sound is much better now, due to a number of things:
- bas and mid drivers were almost new of just reconed so the suspensions are a little looser now
- I changed the amp configuration and with the different amp / driver combinations my mid is much sweeter and the bass is tighter and goes lower
- I went "all carbon" on the interlinks and used the same speaker cabling for all speakers to apart from the ams themselves, the whole chain is using the same equipment
- I optimised equipment polarity for best sound stage (yes, this can be easliy heard in a good setup)
- I added a thick carpet in front of the speaker to minimize reflections from my hard stone floor

"the cd of death" that I know can sound fantastic on an all tube high end system with zingali speakers, now even sounds bearable on my system!

this is "the cd of death" by the way: http://www.amazon.com/Peter-Tchaikovsky-Alexander-Glazunov-Concertos/dp/B000000SJP

[frank23]

I will keep updating my listening experiences here. Last week I did a modification that really affected the sound.

I always used a DC coupling capacitor (of about 40uF) to block DC from the amp output on my 2435 that I use from 1800Hz and up. I always figured DC was bad for compression drivers so I tried different capacitors and settled on a Russian paper-wax capacitor that gave the juiciest sound. But then someone told me that with the DC on my amps of only 24mV, I could connect them without a DC blocking cap, just like cone drivers.

I first connected a 2440 2" driver and listened to noise and switch on clicks, but there was total silence. So I connected the 2435's without DC blocking cap and never looked back. This was the final tweak my system needed. The emotional connection to the music has improved in a great way.

Classical is great, Jazz is great, great recordings are great. I am convinced (I know, I know I am in over my head here) my setup now sounds as good as can be extracted from JBL drivers.

I put high-end friends through a solo bach cello piece and they all mumble something about that the system sounds amazingly coherent although it looks quite thrown together and then say something about that they also want a big living room and paper coned drivers.

So, was I the only one being so stupid using a DC blocking cap on my compression driver when the low DC from my amp made it unneccesary?

[4313B]

So, was I the only one being so stupid using a DC blocking cap on my compression driver when the low DC from my amp made it unneccesary?Basically people who have direct access to replacement parts don't bother with blocking caps. People who don't have access to repair parts or can't afford replacement parts use them. 2435's, being as cheap as they are, can be hooked up directly to pretty much anything. If they blow up, just get another one off eBay. :p

[frank23]

Basically people who have direct access to replacement parts don't bother with blocking caps. People who don't have access to repair parts or can't afford replacement parts use them.

:-) replacement parts for the 2435... ehm, 1100$ you said for the membrane? ok, a lot less on ebay if they are available, lets hope it works out, my amps have no output protection... all in the name of music enjoyment then...

[speakerdave]

. . . . So, was I the only one being so stupid using a DC blocking cap on my compression driver when the low DC from my amp made it unneccesary?

I'll overlook the characterization--I'm using them. Stupid is how I'd feel if I blew a very expensive diaphragm. I may experiment later on to see if there is a difference. For the time being because I am still messing with different setups and connecting, unconnecting and reconnecting; it's too damn easy to make a silly mistake.

I am easily able to choose between amps with the blocking capacitors in place, and I am not finding anything about the sound objectionable, even though I'm using a plain jane solen capacitor. I know I don't understand the electronics well, but I think when that capacitor is of a value to be out of play in the range of frequencies normally being fed from the amp, it ain't doin' anything you could hear.

[frank23]

I am easily able to choose between amps with the blocking capacitors in place, and I am not finding anything about the sound objectionable, even though I'm using a plain jane solen capacitor. I know I don't understand the electronics well, but I think when that capacitor is of a value to be out of play in the range of frequencies normally being fed from the amp, it ain't doin' anything you could hear.

I understand. But although my capacitors were calculated to be out of play one octave below the crossover frequency it was a remarkable change when I removed them totally. I also used Solen Chateauroux 630V MKP types, so certainly not the worst one can find. Maybe it has to do with that the signal goes through it at all frequencies, maybe it has to do with damping by the amp at lower frequencies, I don't know.

But if your DC is low enough, I'd try them without for an evening if possible and see if it makes a difference. Of course the rest of the chain has to be transparent enough in itself, but I think the difference will be heard, or felt.

[speakerdave]

Well, there certainly is something in the line when the capacitor is there, so it is possible that it's audible. I just don't think I have a clear mental picture of what is happening with a capacitor if it is not getting anywhere near shutting down. I think the plates are just acting as electron banks with very short term withdrawals and redeposits. How hard could that be?

When I have some time I will try it with some other drivers with less expensive diaphragms and see if I can hear a difference with and without and with different qualities of capacitors.

[louped garouv]

I'll overlook the characterization--I'm using them. Stupid is how I'd feel if I blew a very expensive diaphragm. I may experiment later on to see if there is a difference. For the time being because I am still messing with different setups and connecting, unconnecting and reconnecting; it's too damn easy to make a silly mistake.

I am easily able to choose between amps with the blocking capacitors in place, and I am not finding anything about the sound objectionable, even though I'm using a plain jane solen capacitor. I know I don't understand the electronics well, but I think when that capacitor is of a value to be out of play in the range of frequencies normally being fed from the amp, it ain't doin' anything you could hear.

that's what I thought, that the protection cap was purposefully out of the "audible passband"

[frank23]

that's what I thought, that the protection cap was purposefully out of the "audible passband"

It is of course, but a cap always has an audible effect. For instance the input cap on your amp is out of the way at 10Hz, but has an audible effect at 10.000Hz. Changing caps changes the sound. Deleting the caps changes the sound, although they have no impedance anymore at the frequencies concerned.

[Mr. Widget]

It is of course, but a cap always has an audible effect. For instance the input cap on your amp is out of the way at 10Hz, but has an audible effect at 10.000Hz. Changing caps changes the sound. Deleting the caps changes the sound, although they have no impedance anymore at the frequencies concerned.I have used a moderate cost polypropylene 47uF protection cap on my 16 ohm mid drivers... ~200Hz first order filter. Directly shorting the cap, i.e. bypassing it with pure copper, I have never heard a change in the sound. I have also done this demo for others... even audio voodoo believers and no one has ever been able to repeatedly identify the cap as being in or out of the circuit.

This was done on a triamped system with the actual crossover frequency approximately 2 octaves above the nominal crossover of the blocking cap. The system was using a TAD TD/TH4003 mid... a very revealing combo. (The replacement cost for a blown TD-4003 diaphragm is $2300... you really don't want an oops!)


Widget

[4313B]

even audio voodoo believers and no one has ever been able to repeatedly identify the cap as being in or out of the circuit.ZOMG! Get outta here! Those guys hear EVERYTHING!

This was done on a triamped system with the actual crossover frequency approximately 2 octaves above the nominal crossover of the blocking cap. The system was using a TAD TD/TH4003 mid... Oh! No wonder! Might as well talk through two tin cans connected with a piece of string. Hardly the stuff of audio voodooists... sorry for the knee-jerk reaction above.

[Ian Mackenzie]

I think it depends on how revealing the whole signal path is (as in further up the food chain) and you need to have a whoe bunch of equipment at your disposal to figure that out.

I mean if one component in the signal chain stamps a big enough sonic foot print on the signal then that is largely what the Tads will be spraying in your ears above all else.

Porchedpm and I proved this several years ago when we were testing the 4343 upgrade project.

If the signal path is sufficiently polluted a particular capacitor might help matters.

[timc]

Ian. Are you saying it is possible to fix a problem by adding another?

Then the opposite should also be true should'nt it? That a cap can bring a balanced system out of balance?


Widget. In your eksperiment you were 2octaves aobve the protection Cap. Frank only 1 octave. That could, repeat could, have an effect. Personally i have the DC protection cap set very low. 3-4 octaves below. Cant say i hear if they are there or not ( H9800clone/2435)


-Tim