DIY-project: JBL Kebnekaise S4365

[bubbleboy76]

This will be my first DIY-project. It will be kind of "open source", so I hope all you guys can ship in with ideas, thoughts and help :)

Components at hand:
476mg compression driver
H4365 horn
1501fe woofer
4365 speaker grills
dbx4820 dsp
Crown CTS-1200 amps

I have a rough plan what to do :)

What would you have done?

"Kebnekaise" is the highest mountain in Sweden. Not especially high though :)

[srm51555]

Not sure what I would do different. Maybe raise the woofer height to ~45cm. Dual 1501fe's or adding a 2216nd as a helper woofer might be interesting since we are naming it after mountains. I look forward to seeing what you come up with.

[JeffW]

With the shorter vertical dimension of the 4365 horn compared to the M2, it should be possible to get the woofer a good height from the floor without making the cabinets too tall.

I look forward to your Kebnekaise design.

[Earl K]

Nice Project!

One suggestion I'll make ( even when bi-amping ) is to include a 10 to 15db pad with a bit of HF compensation ( a capacitor wired as a by-pass over the pad ).

Doing so will help re-align the 2 ( different ) sensitivities ( dynamic capabilities ) by offering a more cohesive ( combined ) wave-front .

One can check for this dynamic cohesiveness ( or lack of ) if one is used to things like the sound of live orchestrated woodwinds ( specifically those instruments using reeds ).
- When their harmonics ( mostly coming from the horn driver ) get out of whack ( & overly dynamic ) one's ears will rebel ( assuming one is familiar with what an oboe sounds like.

:)

[bubbleboy76]

The first concept draft, inspired by many things from this site.


The 1500FE or 1500AL and their variants also make excellent choices for those requiring extended bandwidth for an outstanding two-channel solution. G.T. has stated numerous times that if he had it all to do over again, his "1200 Arrays" would have been "1500 Arrays" with the 1500AL's operating from 25 Hz on up to the Array horns.


Modular design to be able to use the horn both vertical and horizontal. But most important, to be able to get the damn thing up my stairs!

Rounded backside inspired by K2 S9900.

Woofer is raised to be as close as the horn as possible. Another version I have has even more raised woofer, with 850mm high woofer-box, so that the centre of the woofer is at 60cm from the floor. But then the original 4365 speaker grill will not cover the whole front. I can solve the height with higher feets as well.

Do you like it?

[bubbleboy76]

From above.

[hlaari]

your project are in good progress:applaud:

[bubbleboy76]

Not sure what I would do different. Maybe raise the woofer height to ~45cm. Dual 1501fe's or adding a 2216nd as a helper woofer might be interesting since we are naming it after mountains. I look forward to seeing what you come up with.

Raising the woofer, check!

Dual 1501fe's, I would love to! Just send me another pair of 1501fe's, and I will do it!

[bubbleboy76]

With the shorter vertical dimension of the 4365 horn compared to the M2, it should be possible to get the woofer a good height from the floor without making the cabinets too tall.

I look forward to your Kebnekaise design.

:)

[bubbleboy76]

Nice Project!

One suggestion I'll make ( even when bi-amping ) is to include a 10 to 15db pad with a bit of HF compensation ( a capacitor wired as a by-pass over the pad ).

Doing so will help re-align the 2 ( different ) sensitivities ( dynamic capabilities ) by offering a more cohesive ( combined ) wave-front .

One can check for this dynamic cohesiveness ( or lack of ) if one is used to things like the sound of live orchestrated woodwinds ( specifically those instruments using reeds ).
- When their harmonics ( mostly coming from the horn driver ) get out of whack ( & overly dynamic ) one's ears will rebel ( assuming one is familiar with what an oboe sounds like.

:)

Interesting. Thanks. I will consider this.
It would be better to enhance the dynamics of the LF, than reducing it on HF, I guess. Just send me some more 1501fe's please!
The dsp-settings will have to reduce HF much more than LF, to the point of them having almost the same kind of sensitivity, I think.

I will have protection-caps on the compression-drivers, off course.

[bubbleboy76]

your project are in good progress:applaud:

:)
Do you have more of those 1501fe's? ;)

[bubbleboy76]

I have owned real JBL 4365s previously. Some might remember this thread:
http://www.audioheritage.org/vbulletin/showthread.php?36940-JBL-4365-Active-Crossover-settings&highlight=4365+active

2-way active ended up super super nice.

I am very interested to see how an vertical horn will sound in this application, Array-style.

[bubbleboy76]

Mounting diameter: 13.75"
Flange diameter: 15.25"

Does this mean I should make the inner-hole in the baffle exactly 13.75" diameter? Or is it the woofer that is 13.75", so the hole should be slightly larger?

The same question applies to the 15.25" flange diameter, should I do the outer-hole in the baffle exactly 15.25" diameter, or slightly larger?

I do not have the woofers until after easter, and I want to make test-boxes beforehand. That is why I ask this.

[bubbleboy76]

Anyone here good at box tuning calculation?

What would the port-lenght have to be to tune 113L to 28Hz, with dual ports with 69mm inner diameter?

Are woofer T/S parameters necessary for that calculation? I attach them just in case.

Original 4365 ports are roughly 8.5cm in diameter, with a lenght of roughly 15cm each.

Original 4365 box:
1048 x 597 x 429mm outer dimensions
4.2 cu ft (118.9L)
F6 32 Hz Anechoic 28 Hz 2Pi
F3 38 Hz Anechoic 32 Hz 2 Pi

My assumption is that the original 4365 box is tuned to 28Hz. I read that somewhere on this site, I think. Does it seem plausible?

[bubbleboy76]

This pic is so sexy I have to post it again, just to rub it in!

(But I guess most of humanity would consider this the ugliest speaker they have ever seen)

:)

[Flodstroem]

Kebnekaise är inte högt men naggande god! :D

Port tuning 28Hz = 5.5 in in length (2 each with a radius of 1.358 in) ;)

[srm51555]

Does this mean I should make the inner-hole in the baffle exactly 13.75" diameter?

This should be the actual hole diameter.

I do like the vertical waveguide.

[bubbleboy76]

Kebnekaise är inte högt men naggande god! :D

Port tuning 28Hz = 5.5 in in length (2 each with a radius of 1.358 in) ;)

Thanks!
And if each port inner-diameter would be 103mm instead, what would the lenght be then?

I was first thinking of naming the project "Elbrus", the highest mountain in Europe. Especially since it reads out like "Electric noise" in Swedish language.
But aiming for Swedish top-level seems enough at the moment :)

[bubbleboy76]

This should be the actual hole diameter.

I do like the vertical waveguide.

:applaud:

[ivica]

The first concept draft, inspired by many things from this site.

Rounded backside inspired by K2 S9900.

Woofer is raised to be as close as the horn as possible. Another version I have has even more raised woofer, with 850mm high woofer-box, so that the centre of the woofer is at 60cm from the floor. But then the original 4365 speaker grill will not cover the whole front. I can solve the height with higher feets as well.

Do you like it?

Hi bubbleboy,

I can not see any benefits from the "rounded backside", only box volume reduction.

Regards
Ivica

[bubbleboy76]

Hi bubbleboy,

I can not see any benefits from the "rounded backside", only box volume reduction.

Regards
Ivica

The reason for the rounded backside is that I want to be able to place them deep into corners, angled 45 degrees in. But it might be to costly, we'll see.

[ivica]

The reason for the rounded backside is that I want to be able to place them deep into corners, angled 45 degrees in. But it might be to costly, we'll see.

Hi bubbleboy,

I do not think that it would be the best solution to put the speakers deep into the room corner, not to mention the problem about the realization of such boxies.

Regards
Ivica

[bubbleboy76]

Hi bubbleboy,

I do not think that it would be the best solution to put the speakers deep into the room corner, not to mention the problem about the realization of such boxies.

Regards
Ivica

I know there are problems with corner-placements. But there are also large benefits in my room. The sweetspot gets very large, and that is very important for me.
The vertical horn will reduce corner-problems even more, I think. That in combination with damping behind the speaker of SBIR.

I want the speakers to be able to be placed deep into corner, that is one of my design-goals. So I will probably have the BR-ports on the front in the end. For a first-iteration test-box, I will try closed cabinet, and see if the room gain from the corner is enough.

If you would have told me that I will place speaker in corner some years ago, I would have said I had gone crazy. But I have tested a lot, and it really works the best in my room (very dependent on speaker directivity though). JBL LSR305 works extremely well deep into corner in my room, for example. I have amazed some friends with that. They could not believe that it got so much better in the corner, when the common sense says it should sound "shit". The 45 degree angle is critical for it to work.

The realisation is no problem, says my carpenter. I will not build them myself.

Even the original Everest was maybe designed for corner-placement? It is not stated explicitly, but it kind of looks like that too me:
http://www.audioheritage.org/html/profiles/jbl/everest.htm

[Ruediger]

... will reduce early reflections. That are the ones which have travelled from speaker to left or right wall and then back to your ears. Their amplitude response is that of a comb filter.

Ruediger

[bubbleboy76]

... will reduce early reflections. That are the ones which have travelled from speaker to left or right wall and then back to your ears. Their amplitude response is that of a comb filter.

Ruediger

So you promote corner-placement?

[Ruediger]

So you promote corner-placement?

Yes, cause early reflections are hard to deal with, if the room shall look like a living room.

And of course your speakers need to radiate only into 1/8 th space and not into 1/4 th space.

Ruediger

[Flodstroem]

Thanks!
And if each port inner-diameter would be 103mm instead, what would the lenght be then?

Do you have more alternative dimensions? The sim/calc program is rather complicated Due to Im working with this in Windows on my Apple Mac mini and it is efficient to do all sims in one occasion.

I made different sims when I did it for the 69 mm ports just for to see if X-max changes (at the power level of 250W) or if there was different levels of group delay, port air speed etc etc...
I didnt find anything that was better than the 69 mm dia. But if its essential for you to use port tubes that you have in stock then just give me a hint....

Btw whats the X-max for your 1501fe?

[bubbleboy76]

I do not know the xmax.
It was more from a visual standpoint, it would maybe look better with larger BR. So don't bother if it is a hassle. I have no other dimensions in mind.
The biggest variable for me is the box volume in liters, that can change a bit depending on several factors going forward.
I really appreciate the help Flodstroem.

[Flodstroem]

OK I see. But its not any hassle to simulate. ;)

If you are going to change the the cabinets to other dimensions then I can do a couple of sims for to see whats happened internal.
What I mean is the reflections of internal waves, placing of ports etc can be seen in the sim and one can find the most optimal placing of ports as an example for to get the least amount of reflections.

[bubbleboy76]

OK I see. But its not any hassle to simulate. ;)

If you are going to change the the cabinets to other dimensions then I can do a couple of sims for to see whats happened internal.
What I mean is the reflections of internal waves, placing of ports etc can be seen in the sim and one can find the most optimal placing of ports as an example for to get the least amount of reflections.

:applaud:

[bubbleboy76]

My plan is to use 2 x 12mm mdf with 1mm damping glue in between (25mm total).
Constrained layer damping. I really beleive in that concept.
And then some 15mm or so mdf extra on the baffle, for the woofer to be flat.
Bracing to be done with something stiffer than mdf, probably plywood.

[bubbleboy76]

Flodstroem, it would be interesting to know if a tuning of 25Hz would work with 113L. Or which volume would be needed for that.
And where on the front-baffle you would place the ports.
And which tuning frequency original 4365 box has, based on the data I provided (4.2 cu ft volume and dual 8.5cm diameter ports with lenght of 15cm).

[Flodstroem]

Im going to check that but Im to busy right now. I can do it Sunday evening as the earliest
X-max for the 1501fe seems to be approx 9.5 mm what I understand from this:
75881

[Flodstroem]

Flodstroem, it would be interesting to know if a tuning of 25Hz would work with 113L. Or which volume would be needed for that.
And where on the front-baffle you would place the ports.

And for your project its essential that the woofer should be located as high as possible in the cabinet or correct me if Im wrong...............

[bubbleboy76]

Correct.
For 2 reasons:
1. Keeping woofer/horn cc distance as low as possible.
2. Getting center of woofer as close as possible to 60-65cm from floor (1/4 distance floor-roof).

[Ruediger]

I did a quick lookup in Thiele's paper.

An alignment which fits is a QB3 somewhere (interpolated) betweeen alignments #2 and #3.

Alignment #3 results in f3 = 53 Hz, Vb = 49 Liters, fb = 42 Hz.

That is a ballpark figure. You can vary that a bit, but not much.

Ca. 50 Hz from a 50 liter box is quite attractive.

Ruediger

[bubbleboy76]

I did a quick lookup in Thiele's paper.

An alignment which fits is a QB3 somewhere (interpolated) betweeen alignments #2 and #3.

Alignment #3 results in f3 = 53 Hz, Vb = 49 Liters, fb = 42 Hz.

That is a ballpark figure. You can vary that a bit, but not much.

Ca. 50 Hz from a 50 liter box is quite attractive.

Ruediger

This is a bit over my head, at the moment. Bare with me :)
Is this vented or close box you are taking about?

This is much higher tuning than I expected. I want as much fullrange speaker as possible (including room gain).

You are indicating that original 4365 (119L) is more than twice as large as it should be?

50L would be very nice so I could reduce the dimensions more to my liking. But I do not want to have to have subs. They must be able to reproduce music by themselfes.

[ivica]

This is a bit over my head, at the moment. Bare with me :)
Is this vented or close box you are taking about?

This is much higher tuning than I expected. I want as much full-range speaker as possible (including room gain).

You are indicating that original 4365 (119L) is more than twice as large as it should be?

50L would be very nice so I could reduce the dimensions more to my liking. But I do not want to have to have subs. They must be able to reproduce music by themselves.

Hi bubbleboy76,

I can only imagine (using 1501FE driver) the bass box of round 156Lit, tuned at 36Hz ( with TWO duct internal diameter 105mm, and the length about 130mm each), so I can imagine to reach down to 35Hz (-3db) even less if room influence assumed.

regards
ivica

[bubbleboy76]

One option I have thought about is to use M2 box volume (140L) and tuning, togheter with M2 dsp for LF, as a starting point.

But 140L feels too large for my wanted speaker size. Going for 4365 box volume of 119L is more ok for my wanted design.

Another option would be to try to copy the K2 S9900 (96L) tuning.

(I really appreciate all the help).

[bubbleboy76]

Closed box with corner gain and a lot if dsp feels to me "easier" to get ok. With my limited knowledge.

[Ruediger]

This is a bit over my head, at the moment. Bare with me :)
Is this vented or close box you are taking about?


The oscillator equation (for circuits made from R, L & C or sytems made from masses, springs and friction) is the same in mechanics and in electrodynamics (see electroacoustical or electromechanical analogies). The math is the same. One can apply the mathematical techniques from electronics to mechanical systems.

The equivalent electrical circuit for a loudspeaker in a vented box looks very messy and hard to handle. Thiele found out that if certain assumptions are justified the equivalent circuit can be simplified. A speaker in a vented box is a highpass filter of order 4.

These filters have been investigated, there are Butterworh, Bessel, Cauer etc. They are described by polynomials in frequency and the coefficients are made up from the so-called Thiele parameters.

Thiele compiled a table with alignments such as Butterworth filter of order 4. Given the Thiele (-Small) Parameters you can jump into that table and look up matching alignments. Within a few seconds you can tell what is possible with a certain speaker and what not.

You can find the Thiele Paper here in this forum: General Audio Discussion, 3rd entry: Technical References, 11th entry therein.

In many cases you will need to interpolate between alignments. And you can make your Qt (speaker Q) fit. You can experiment with different parameters and plot the result. At least you get a starting point for an educated guess.

Ruediger

[ivica]

The oscillator equation (for circuits made from R, L & C or sytems made from masses, springs and friction) is the same in mechanics and in electrodynamics (see electroacoustical or electromechanical analogies). The math is the same. One can apply the mathematical techniques from electronics to mechanical systems.

The equivalent electrical circuit for a loudspeaker in a vented box looks very messy and hard to handle. Thiele found out that if certain assumptions are justified the equivalent circuit can be simplified. A speaker in a vented box is a highpass filter of order 4.

These filters have been investigated, there are Butterworh, Bessel, Cauer etc. They are described by polynomials in frequency and the coefficients are made up from the so-called Thiele parameters.

Thiele compiled a table with alignments such as Butterworth filter of order 4. Given the Thiele (-Small) Parameters you can jump into that table and look up matching alignments. Within a few seconds you can tell what is possible with a certain speaker and what not.

You can find the Thiele Paper here in this forum: General Audio Discussion, 3rd entry: Technical References, 11th entry therein.

In many cases you will need to interpolate between alignments. And you can make your Qt (speaker Q) fit. You can experiment with different parameters and plot the result. At least you get a starting point for an educated guess.

Ruediger

Hi,

Not to say that there are some Vented box calculators on Internet:

http://www.mh-audio.nl/reflexboxcalculator.asp
http://www.micka.de/en/
http://www.ajdesigner.com/speaker/bcv.php
http://www.ajdesigner.com/speaker/ajvented.php
http://www.troelsgravesen.dk/ports.htm

etc

ivica

[bubbleboy76]

I think I will start with LF test-boxes that approximates the original 4365 volume and tuning:

Testbox with 4365 LF internal volume (4.2cu ft / 119L)
External dimensions:
Width 560mm
Height 1000mm
Depth 310mm
About 126L without bracing (119L with 7-8L bracing)
25mm mdf
Woofer at top of front baffle. 2 ports at bottom of front baffle.
A thin layer of damping on the inside, like 1/2" thick.

I have choice of BR-tube with 69 or 103mm internal diameter:
http://www.hifikit.se/tillbehor/aeroport-4
http://www.hifikit.se/tillbehor/aeroport-3

Flodstroem, can you help me calculate the best port dimension and lengths for tuning this box to 20, 25, 28 and 32Hz, respectively?

[bubbleboy76]

Found this post about 1501fe. It is probably 32Hz tune on the 4,2 cu ft box in 4365 then.


Greg used it in a 4.2 cubic foot volume tuned to 32 Hz and yes, WinISD does yield smaller volumes with less bandwidth.

I do have a pair of enclosures in progress that are something like 3 cubic feet tuned a bit higher for more impact. The AutoCAD drawing is on my laptop which I don't have access to at the moment. All the MDF is already in the garage stacked next to the table saw and, true to form, it's been there for months. :banghead:

My plan was to build "B4" volumes with the option to tune them as "B6" volumes for response to 25 Hz. I figured that was as low as I wanted them to go.


I'm not sure what volume/tuning 1audiohack evaluated a pair in. I'm not sure what volume/tuning RobH3606 plans on evaluating the same pair in. I'm not sure what volume/tuning hlaari plans on using. Jerry Moro wanted to know how we all used them and whether or not we liked them. He mentioned that he didn't have a whole lot of experience with system design so he was interested in our feedback.

The 1500AL in the 4.6 cubic foot volume tuned to 28 Hz is a real work of art. The 1501FE won't beat it, but it should be very nice in its own right. Plus it isn't as heavy or expensive, albeit just as impossible to obtain. Rather irritating actually. To this day neither Greg nor Jerry seem to be able to fathom why it is impossible to get these transducers or their recone kits. I've read some of their internal emails and they seem totally perplexed. I suspect Harman simply doesn't want to stock anything and that means not building spares.

[Flodstroem]

I think I will start with LF test-boxes that approximates the original 4365 volume and tuning:

Testbox with 4365 LF internal volume (4.2cu ft / 119L)
External dimensions:
Width 560mm
Height 1000mm
Depth 310mm
About 126L without bracing (119L with 7-8L bracing)
25mm mdf
Woofer at top of front baffle. 2 ports at bottom of front baffle.
A thin layer of damping on the inside, like 1/2" thick.

I have choice of BR-tube with 69 or 103mm internal diameter:
http://www.hifikit.se/tillbehor/aeroport-4
http://www.hifikit.se/tillbehor/aeroport-3

Flodstroem, can you help me calculate the best port dimension and lengths for tuning this box to 20, 25, 28 and 32Hz, respectively?




Yea I can do it tomorrow I guess ;)
Good you have all the dimensions listed. That helps.

[bubbleboy76]

I updated the concept a bit. Now it is M2-box volume and port tuning. This is better I think.
I also reduced wall-thickness to 21mm to reduce weight.
BR-port lenght should be someting similiar to M2, if using the same volume, tuning and port-diameter, right?

[Flodstroem]

What dimension of the

Width 560mm
Height 1000mm
Depth 310mm

have you changed ? :)

[bubbleboy76]

What dimension of the

Width 560mm
Height 1000mm
Depth 310mm

have you changed ? :)

Hard to say... I redesigned the main-concept to get 20L more volume.
The test-box is not valid any more. I thought you left me hanging :)

[bubbleboy76]

I will not do a testbox, I changed my mind.
I will go straight for the dessert.
Flodstroem, there will be no more changes now. Can you calculate approx. port-lenght for tuning to 20,25 and 28Hz for the new concept?

[Flodstroem]

Yes I can do some plots, have actually done some............. you are not left hanging ;)

[Flodstroem]

I have done the sims. What I can say is that the 20Hz dont look any good. >100 watts less usable power resistance, X-max reaches at approx 30 Hz while the higher tunings manage 500 watts easily and X-max reaches below the tuning frequency at approx 21-23 Hz ;)

SPL is a bit different between the tuning fr. You will need some boost below 60-70 Hz I believe. But if using an active xover this isnt a problems.

What factor/variable is most important for your project?

28 Hz port length 4.5" (2 x 69 mm)
28 Hz port length 12" (2 x 103 mm)
25 Hz port length 5.75" (2 x 69 mm)
25 Hz port length 14" (2 x 103 mm)

This is the plot of the 20 Hz tuning @ 375 watts and 2 x 69 mm tubes
75922

[Flodstroem]

Btw, the ports (center of) should be located 32" below the top end (internal). Woofer (center of) approx 8-10" below top end (internal). ;)
If you shoos to place the ports on other locations then I cant guarantee from lack of reflection/standing waves etc........

[bubbleboy76]

Thanks!

Hard to say which factor is most important. After EQ and room gain I would like to be able to play down to 25hz, with +9db gain on 25-135Hz relative higher frequencies, if possible.
I live in apartement and do not play extremely loud.

I can start with about 25Hz tuning then, and later shorten the ports if 28Hz seems to be better.

[bubbleboy76]

Btw, the ports (center of) should be located 32" below the top end (internal). Woofer (center of) approx 8-10" below top end (internal). ;)
If you shoos to place the ports on other locations then I cant guarantee from lack of reflection/standing waves etc........

Those positions seems hard to fulfill with a box of 850mm external height. And I want minimal woofer/horn CC-distance.
I will put woofer as high as possible, and the ports as low as possible, on the front baffle.

[Flodstroem]

Those positions seems hard to fulfill with a box of 850mm external height. And I want minimal woofer/horn CC-distance.
I will put woofer as high as possible, and the ports as low as possible, on the front baffle.

You cant come closer than approx 7.5-8" so a 8-10" distance from the top end seems to be most practical or have I missed something?

Btw, havent you specified a hight for the cabinet to 1000 mm ?

[bubbleboy76]

850 height
560 width
rounded bakside
see latest pic

[bubbleboy76]

Some more detail added.
BR-ports has to be 150mm up from bottom to be able to be covered by original 4365 grill.

[pos]

Nice! :)

[Flodstroem]

I have done simś for your last model of cabinet.

You could use either the 28 or 25 Hz tuning. Both of them manage approx 500W power down to at least 21 Hz. But you will need a high pass filter to protect the woofers from frequencies below that point.

The sims says port lengths of:
28 Hz = 5" (127 mm)
25 Hz = 6" (153 mm)

2 ports and a dia of 69 mm in each cabinet placed 226 mm up from bottom (28 Hz tuning)
But, thats not optimal for the 25 Hz tuning. Best port location for the 25 Hz tuning is 277 mm up from bottom for to avoid unwanted reflections.
Its up to you to make a choice........... ;)

Woofer placement as high as possible.

Also the simś shows (but not here) a better efficiency than with your suggested 103 mm tubes. Your choice of the 69 mm seems to be
optimal in theis case. :)

Here you could see a 500 Watt plot/sim for the 25 Hz tuning and X max.

75937

[bubbleboy76]

Wow! Thank you very very much!

I updated the concept with your changes.

Was there pages missing in that last report?

[bubbleboy76]

Does flared ports alter this calculation much?

[Flodstroem]

Flared ports has nothing to do with tunings. They are flared for to be as silent as possible when the air is moving in and out ;)

[bubbleboy76]

In the TS-document for the 1501fe woofer a kind of addon-gasket is shown, and I think the mounting-dimensions includes this.
Anyone who knows the mounting diameter and flange diameter and flange-depth without the "add-on"-gasket? I think I would maybe not use it, but another thin rubber-gasket instead.
I think 1501fe has the same dimensions as the other 1500/1501-variations.
Trying to design box without the woofers...
/Magnus

[JeffW]

The gasket doesn't go over the edge of the mounting flange, so the basket diameter is the true overall diameter.

This is a pair of mine, I can measure the exact OD of the basket if you want to compare against the printed dimensions.

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=53679&stc=1&d=1321577130

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=53678&stc=1&d=1321577113

[bubbleboy76]

The gasket doesn't go over the edge of the mounting flange, so the basket diameter is the true overall diameter.

This is a pair of mine, I can measure the exact OD of the basket if you want to compare against the printed dimensions.

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=53679&stc=1&d=1321577130

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=53678&stc=1&d=1321577113

Yes please, that would be very helpful. Thanks.
I am a bit confused right now, what is a gasket, and what is not.
on your pics, there is no gasket, right?

[JeffW]

Yes please, that would be very helpful. Thanks.
I am a bit confused right now, what is a gasket, and what is not.
on your pics, there is no gasket, right?

On the older drivers, there was a foam "gasket" that covered the edge of the surround. It would only act as a true gasket if the driver was mounted to the rear of the baffle, it really served no sealing purpose when the driver was mounted to the front. These appear to serve a similar purpose, just a cosmetic device to cover the surround edge as best I can tell, but now make of a harder rubber as opposed to the segmented foam as before..

[Mr. Widget]

Flared ports has nothing to do with tunings. They are flared for to be as silent as possible when the air is moving in and out ;)Yes, but a flared port does change the tuning frequency. Most box calculators assume a non flared port, if you substitute a flared port, the tuning will change a bit.


Widget

[Flodstroem]

Yes you are right Widget. I read a I think it was a patent or a scientific report from JBL regarding flared ports and whats happened round the openings av the port. There was also som calculations regarding the issue of changes of tunings frequency or calculations for port length
I didnt find the report now but what I remember there was no huge difference. After all if building a speaker from scratch one is forced to check tuning frequency no matter what program was used for the calculations for to get everything to work as intended......... :D

[grumpy]

for scale of the "issue":

just ran an example that used a 4" dia x 17" long duct and resonance at ~400Hz (40Hz system tuning)
... above was with no flares.

one flare: 16.5", 410Hz resonance, same 40Hz system tuning
two flares: 16.1", 421Hz resonance, same 40Hz system tuning

model doesn't deal with differences in turbulence in regard to "chuffing" noise, but I would expect less
when using flares of a significant radius.

[JeffW]

OD of the basket is right on the 15 1/4" spec, not surprising.

I never paid much attention to the first couple of pages of the transducer info post, but the picture there and cut away are accurate as to the construction.

http://www.audioheritage.org/vbulletin/showthread.php?33555-1501fe

[bubbleboy76]

Thank you Jeff! So the outer hole inte the baffle needs to be a little little bit larger than 15.25" then, like 15.3" so it is not to tight? Any recommendations on hole OD size?

[bubbleboy76]

for scale of the "issue":

just ran an example that used a 4" dia x 17" long duct and resonance at ~400Hz (40Hz system tuning)
... above was with no flares.

one flare: 16.5", 410Hz resonance, same 40Hz system tuning
two flares: 16.1", 421Hz resonance, same 40Hz system tuning

model doesn't deal with differences in turbulence in regard to "chuffing" noise, but I would expect less
when using flares of a significant radius.

Interesting. Is higher resonant frequency better, in some regard?

Flodstroem, did you see where my theoretical port resonant frequency will be?

[grumpy]

If it moves away from in-band signals or resonant responses for that driver, sure.

The change is pretty marginal though, vs changing port diameter or number of ports.

[Odd]

Troels Gravesens has made some measurements.


Vent flange - does it have an impact on Fb?
http://www.troelsgravesen.dk/vent_tuning.htm

Tuning frequency vs. flanging:
No flange: 34.6 Hz
One end flanged: 33.9 Hz
Both ends flanged: 33.7 Hz.
Well, not much to write home about from this study! From no flange to double flange we lower the vent tuning by 0.9 Hz.

[pos]

I used that calculator, and it gave me accurate results:
http://www.psp-inc.com/tools2.html

It is meant for the flared precision port (http://www.psp-inc.com/products_3.html)s sold on parts express, but works just as well for the JET70 ones that can be found in europe

[bubbleboy76]

I used that calculator, and it gave me accurate results:
http://www.psp-inc.com/tools2.html

It is meant for the flared precision port (http://www.psp-inc.com/products_3.html)s sold on parts express, but works just as well for the JET70 ones that can be found in europe

Nice!
This one gave me a little bit longer port-lenght than Flodstroem suggested.
6.9" lenght for 28Hz tuning.
8.9" length for 25Hz tuning.

(Volume of box:5 cu ft, Port-diameter 2.7)

[bubbleboy76]

I have bought some more of the "little things".

http://www.hifikit.se/tillbehor/aeroport-3 (http://www.hifikit.se/tillbehor/aeroport-3) (BR-port)
http://www.hifikit.se/tillbehor/akustik ... iel-farull (http://www.hifikit.se/tillbehor/akustikmaterial/dampmateriel-farull) (Internal damping)
http://www.hifikit.se/tillbehor/tatningslist (self-adhesive gasket)
http://www.thomann.de/se/neutrik_nl2_fx ... arch_prv_3 (http://www.thomann.de/se/neutrik_nl2_fx.htm?ref=search_prv_3) (Connector)
http://www.thomann.de/se/neutrik_nl2mp_d_typ.htm (Connector)
http://www.thomann.de/se/neutrik_scdp_0 ... arch_prv_1 (http://www.thomann.de/se/neutrik_scdp_0.htm?ref=search_prv_1) (Connector gasket)
http://www.thomann.de/se/adam_hall_4909 ... s_pack.htm (http://www.thomann.de/se/adam_hall_4909_gummifuss_pack.htm) (Feet)

[Flodstroem]

Nice!
This one gave me a little bit longer port-lenght than Flodstroem suggested.
6.9" lenght for 28Hz tuning.
8.9" length for 25Hz tuning.

(Volume of box:5 cu ft, Port-diameter 2.7)

Yea, that could be the case but you have calculated only by volume but my sims are based on a real cabinet with exact your specified
internal dimension including damping mtrl woofer and port location. Might be some differences due to that. But no matter how you do the
calculations, this is only a hint of what length you should start with. Real tuning will be done after checking a finished build and that will be very
exciting :D

[bubbleboy76]

The way of testing actual tuning frequency without measuring impedance, I read it somewhere here but forgot it.
Playing test-tones and feel with the fingers when the port is "excited"?

[srm51555]

The way of testing actual tuning frequency without measuring impedance, I read it somewhere here but forgot it.
Playing test-tones and feel with the fingers when the port is "excited"?

Here (http://www.audioheritage.org/vbulletin/showthread.php?37659-Project-M2-DIY-Thread&p=388697&viewfull=1#post388697) and the post after are good ways to test.

[bubbleboy76]

Thanks! Saving it here for me to remember.


Another (less precise, +/- 1Hz) method is to use a signal generator (I use a simple iphone app called "signal gen" for this) while touching the cone and find the frequency for which the cone movement is at a minimum (and air movement from the ports maximal).

With this method I found my current M2 build was tuned to around 24 or 25Hz (the tubes are too long, I prefer to aim for a lower tuning frequency and then cut them step by step...).

[bubbleboy76]

Some minor details updated.

[bubbleboy76]

Small additions again.
I got the BR-ports, and they did not have the same dimensions as stated on the website where I bought them. But the important one was correct, the internal tube diameter.
I will be able to pull out the BR-port without removing the woofer, that is a good thing. The inner flared end is smaller than the mounting hole will be.

I also got the sheep wool damping. This is an ecological project! ;)
But it is thicker than I thought. 40mm. Is this good or bad? M2 has like 20mm damping thickness, I think. 4365, I do not know. Maybe I should not cover all the internal walls?

[bubbleboy76]

Where can the speaker grill connectors used in JBL 4365 be bought?

I found this at home, I think it is from the 4365s.

Outer diameter 12mm
inner hole diameter 5mm
depth 20mm

[bubbleboy76]

4365 Exploded view.

[Flodstroem]

If you are not locked on those JBLś, HiFi-Kit has some that I have used for years. But they are not "rock strong" tough ;)
http://www.hifikit.se/tillbehor/galler-frontskydd/frontfastsattning

[bubbleboy76]

The "problem" is that I will use the original 4365 speaker grille.

[pos]

If the pins are similar to the one on S4700/M2 grills then you can try part 333249-001 (L820 grill cup black)
Got them from speaker exchange for a whopping $2.80 each.

[bubbleboy76]

If the pins are similar to the one on S4700/M2 grills then you can try part 333249-001 (L820 grill cup black)
Got them from speaker exchange for a whopping $2.80 each.

Nice. That is the same partnumber as item 8 on the 4365 exploded view. I could not find it on their website, and I did not want to ask them because they are a bit tired of me.

[bubbleboy76]

I still have not got a quote from my carpenter on the rounded shape box. I think he do not want to start anything before I have all the components.

I have a plan B, if the round shape gets too expensive to build. Something like this:
http://errnum.com/html/coax_speaker_build.html

[Odd]

Carpenter Sweden.
A few years ago there was an old nice man with a workshop on the west coast who made some enclosures for me.
I do not know if he is still working, but the website is still there.
JOA Snickeriverkstad AB (http://www.joasnickeri.com/index.htm)

[bubbleboy76]

Carpenter Sweden.
A few years ago there was an old nice man with a workshop on the west coast who made some enclosures for me.
I do not know if he is still working, but the website is still there.
JOA Snickeriverkstad AB (http://www.joasnickeri.com/index.htm)

Thanks.
I actually asked them about making a simple testbox some time ago, and got this answer:



Tyvärr kan jag inte hjälpa dig med detta projekt, då jag inte arbetar med MDF längre.



Med vänlig hälsning

Ian Garrett

JOA Snickeriverkstad AB


"I am not working with MDF anymore".

Is this the same guy you used Odd?

[Odd]

Yes it was Ian.

[bubbleboy76]

Anyone having a guesstimate how much volume (L) the 1501fe woofer will reduce the box inner volume?

[bubbleboy76]

Anyone having a guesstimate how much volume (L) the 1501fe woofer will reduce the box inner volume?

This calculator gives me 5.34 liters for the woofer.

https://www.diyaudioandvideo.com/Calculator/SpeakerDriverDisplacement/Help.aspx/

[bubbleboy76]

I did a quick lookup in Thiele's paper.

An alignment which fits is a QB3 somewhere (interpolated) betweeen alignments #2 and #3.

Alignment #3 results in f3 = 53 Hz, Vb = 49 Liters, fb = 42 Hz.

That is a ballpark figure. You can vary that a bit, but not much.

Ca. 50 Hz from a 50 liter box is quite attractive.

Ruediger

I have started to sketch on another alternative LF box design. The intention with this design is a "minimal" sized box, that can be placed deep into the room corner, if I should want to.

The box shape was first outlined as a rectangle with 40cm sides (because I want about 56cm total width, the hypotenuse), then I cut away triangles to make it just fit the woofer, and reach 50L net volume.

Also a less expensive shape, without the rounded backside.

I used the 49 litres volume (suggested by Ruediger) as target, and added one litre for "safety". So 50L. I tried a speaker simulator program called Basta!, that also suggested about 49 litres as optimal box volume for this woofer.

The rationale for this design is that I know I will probably end up with subwoofers in the end anyways, so these speakers will not have to play full range. And I also would like to try my corner-speaker-concept "all-in". This design is intended to be able to dock 100mm damping (like basotect) to the sides when put in the room corner.

Flodstroem, can you help me simulate where I should put the bass port, and if I can use my 69mm ports when aiming for the Ruediger suggestion of f3 = 53 Hz, Vb = 49 Liters, fb = 42 Hz? How much damping on the walls would be good? I have 40mm thick sheep wool that can be used.

(In the sketch the liter numbers for bracing and woofer volume are interchanged by mistake)

If I choose this kind of box, my thought is to first try it as closed box, to see if the corner-gain + dsp will be enough. And add BR-port later, if it is needed. In the closed scenario the box would be filled with damping.

Comments and thoughts are welcome!

[Ruediger]

<quote>

I did a quick lookup in Thiele's paper.

An alignment which fits is a QB3 somewhere (interpolated) betweeen alignments #2 and #3.

Alignment #3 results in f3 = 53 Hz, Vb = 49 Liters, fb = 42 Hz.

That is a ballpark figure. You can vary that a bit, but not much.

Ca. 50 Hz from a 50 liter box is quite attractive.

</quote>



You still need to interpolate between alignments 2 and 3. I did not do that. The figures I gave should show the magnitude, not more.


I attach a flowchart which should give you the same cabinet parameters as an interpolation between alignments 2 and 3.


Ruediger

[bubbleboy76]

It is over my head to do that interpolation.

[cooky1257]

FWIW, My understanding of the research paper that begat the profiled ports currently employed by JBL was that flare made little difference to real world tuning - was dictated by csa of the narrowest point x actual length. from the paper 'Maximising performance from loudspeaker ports' ;
"An initial samples of 6 port tubes, all of length 120mm and minimum diameter of 60mm were made with NFR’s of 0,0.125,0.25,0.5,0.667,and1.0. In addition, all profiles had a small 12mm blend radius on both ends to avoid sharp edges, as well as a 140mm inner baffle for symmetry.
Unexpectedly, port tuning frequency was only weakly dependent on flare. Clearly, theport length and minimum throat diameter appear to be the main determinates of tuning. As port flare becomes more pronounced, the end correction, as typically calculated based on the radius at the mouth, overestimates the reactive air mass present. A better way topredict tuning appears to be basing the length correction on minimum throat diameter instead of maximum diameter." This method proved to be accurate to within 2%.

An observation on the bass enclosure design is perhaps as you are going to the trouble of a curved back you may be missing an opportunity to slope the top to more closely mirror the underside of the vertical horn.think B&W, This would allow the box to be slimmer slightly more elegant from the front while keeping your volume.

[bubbleboy76]

Hlaari, I have been receiving fake emails in your name from: hla08@outlook com
Be careful! They tried to make me send money to bank-account in Benin, Africa, in your name.
Maybe your email has been hacked? They knew things we have talked about.
I think you should change your email password, to start with (I will do the same).

[bubbleboy76]

Some small details added.
Some internal measurements can be seen in the attached pdf.

[bubbleboy76]

An observation on the bass enclosure design is perhaps as you are going to the trouble of a curved back you may be missing an opportunity to slope the top to more closely mirror the underside of the vertical horn.think B&W, This would allow the box to be slimmer slightly more elegant from the front while keeping your volume.

I have been thinking about phased/angled top of the box, like Array series. But I do not like the looks of that.

[cooky1257]

I have been thinking about phased/angled top of the box, like Array series. But I do not like the looks of that.

No problem;-)

Are you planning to include a plinth/feet/base?

[bubbleboy76]

I will try soft feet decoupling the speaker low frequencies from the floor, in the end, when I know the exact weight-distribution of the speaker.

The only problem with that approach is maybe this:


You will eat the bass kick immediately if any enclosure movement is allowed. The woofer kicks really hard and if any energy is consumed moving (rocking) the enclosure due to it not being properly coupled to the floor, you will lose bass kick and impact. The proper use and need for spikes (or equivalent) is not BS. It is based in sound theory and is easily demonstrable.

I will start with them on casters, I think.

[cooky1257]

I will try soft feet decoupling the speaker low frequencies from the floor, in the end, when I know the exact weight-distribution of the speaker.

The only problem with that approach is maybe this:



I will start with them on casters, I think.
Sorry,your response to the above quoted comment regarding spikes from Greg Timbers is to put your speakers on wheels. Ok good luck with that.

[bubbleboy76]

Sorry,your response to the above quoted comment regarding spikes from Greg Timbers is to put your speakers on wheels. Ok good luck with that.

I did not mean it that way. The wheels are not for solving the GT issue.

I want them on wheels so I can try, for example, having the woofer 1m out from the corner (to avoid corner-SBIR around 200-300Hz), and the horn on the wall, with correct dsp delay making them play togheter. And other placement strategies.

[BMWCCA]

I have my 4345 on casters with no apparent ill effects. :dont-know:

[bubbleboy76]

I played around in the free speaker designer software Basta!
http://www.tolvan.com/index.php?page=/basta/basta.php

First the JBL 1501fe woofer data entered (hopefully in the correct manner).

[bubbleboy76]

Basta! suggested the following box (with Keele algorithm) for 1501fe:

Vb=53,27L
Fp=44,79Hz

I assume Fp is the bassreflexport tuning frequency.

I wonder if this correlates to the interpolation Ruediger suggested?

[bubbleboy76]

Calculated system response for vented box (using the above suggested box) vs closed box (using the same box-size) with linkwitz-transform.

Graph shows calculated response for 1m 2,83 volt.

(no room gain, or baffle step, included)

Qb used for closed box=5 (much damping)
Qb used for vented box= 20 (moderate damping)

Closed box looks really nice too me, what I am missing!? 93dB sensitivity down to 20Hz.
There are 6dB more bass about 50-150Hz for vented, but I get smoother and deeper curve with closed. And the room gain will add a lot to this. Assuming I can add something like linkwitz-transform with my dbx4820.

With the assumption of having subwoofers to crossover to downwards, would you recommend me to do closed or vented box for the woofer? (I know you are going to say vented...)

[bubbleboy76]

Closed box comparison with and without linkwitz-transform.

[bubbleboy76]

Adding this kind of linkwitz-transform-DSP, would it be any problem technically? Maybe pos can comment that?
There are quite some gain to add, is it too much to do with digital dsp, you think?

[Adhoc]

I will try soft feet decoupling the speaker low frequencies from the floor, in the end, when I know the exact weight-distribution of the speaker.

The only problem with that approach is maybe this:

http://www.audioheritage.org/vbulletin/images/misc/quote_icon.png Originally Posted by gtimbers http://www.audioheritage.org/vbulletin/images/buttons/viewpost-right.png (http://www.audioheritage.org/vbulletin/showthread.php?p=386898#post386898)
You will eat the bass kick immediately if any enclosure movement is allowed. The woofer kicks really hard and if any energy is consumed moving (rocking) the enclosure due to it not being properly coupled to the floor, you will lose bass kick and impact. The proper use and need for spikes (or equivalent) is not BS. It is based in sound theory and is easily demonstrable.

I will start with them on casters, I think.

Timbers is correct when he says you should prevent the speaker from rocking back and forth. Using (common) spikes is not a good way though as you don't want the speaker coupled to the floor. You should avoid any vibrations from the speaker transmitted to the floor or room structure, giving off resonances. That means a decoupled speaker (isolated with springs or compressed rubber feet => a wobbly speaker if free standing) while at the same time immovable and fixed in its position. Both together can be tricky to accomplish but can be solved. A post on positive things about decoupling speakers: https://www.gearslutz.com/board/11882181-post22.html (That whole thread is good reading.)

[pos]

A post on positive things about decoupling speakers: https://www.gearslutz.com/board/11882181-post22.html (That whole thread is good reading.)
The important part in the linked post is the "very heavy slab base, many times the weight of the speakers (ours is 960kg)". This prevents most of the rocking.

[hpham]

Question: where to buy all the JBL drivers?

[bubbleboy76]

Question: where to buy all the JBL drivers?

That is the million dollar question.

I bought mine second-hand from a member on this forum.

[JeffW]

That is the million dollar question.

I bought mine second-hand from a member on this forum.
.

That's good to hear, I just saw your WTB ad in the marketplace and was wondering if you had done all this preparation without having secured the drivers yet.

[bubbleboy76]

2 more woofers would spicen up the mix a bit :)

[hpham]

That is the million dollar question.

I bought mine second-hand from a member on this forum.

Because I can't find the shop or distributor to sale modern driver of your nice project. I asked because I want to built one and really don't know where to buy.

[bubbleboy76]

Because I can't find the shop or distributor to sale modern driver of your nice project. I asked because I want to built one and really don't know where to buy.

These luxury drivers are not for sale. You can not buy them from JBL.

[pos]

2216nd variants as well as many current gen 1.5" drivers and horns are readily available tho.
You can also put Truextent Be diaphragms into a (possibly used) 1.5"/4" driver and get quite close to a 476Be.

[JeffW]

These luxury drivers are not for sale. You can not buy them from JBL.

Took over a year and a screw up on Harman's part, but I actually did buy a pair of 1501FEs from them. But this was back when they had drivers for sale by system on their website, there's not even any way to try to buy the drivers now.

[Ruediger]

It is over my head to do that interpolation.

Hi,

Here are the interpolations. Run them in a simulator software before cutting wood.

Linear interpolation in Thiele Table between alignments #2 and #3:

f3 = 57.9 Hz
fb = 45.4 Hz
Vb = 38.9 liter


We can as well make the driver fit the table. The driver's Qt depends on the amplifier's output impedance (equation 70 in the Thiele paper). The DC resistance of the speaker cables (back and forth!) and of crossover inductors which are in series with the driver gets lumped into that impedance as well. The net amplifier output impedance is ( 8 Ohms / amp's damping factor ). A typical value is 200. This yields ( 8 Ohms / 200 = 0.04 Ohms ).

1 / Qt = ( 1 / Qm ) + ( 1 / Qe ) * [ Re / ( Rg + Re ) ]

Alignment #3

Qt = .259 (our goal)
Re = 5.42 Ohms
Qm = 4.25
Qe = 0.25
Rg = 0.559 Ohms result: amp's output impedance + cables + inductors

f3 / fs = 1.77 -> f3 = 52.2 Hz
f3 / fb = 1.25 -> fb = 41.8 Hz
Vas / Vab = 4.46 ->Vab = 48.9 liter


Keele's Table:

Vb = 54.4 liter
f3 = 56.56 Hz
fb = 44.76 Hz

Keele, force 50 liter:

f3 = 61.6 Hz
fb = 47.3 Hz
R = 0.38 dB (R = Ripple)

Keele, force 50 Hz

Vb = 75.9 liter
fb = 41.3 Hz
R = -0.89 dB (R = Ripple)

There is a discrepancy between the interpolated values and the values from Keele's table.

Thou shalt build prototypes!

Ruediger

[Ian Mackenzie]

You may wish to acquire Bassbox simulator software

But all models are based on assumptions

The Qb3 is a maximally flat alignment that in fact does not exist once the loudspeaker is in the real environment

For this reason experienced engineers like GT account for typical placement in a room and then design the box tuning to take suit

As a result we have the "banana.

In the room the bass sound crisp and smooth

TheQB3 in comparison can sound fat and bloated

[Ruediger]

<snip>
The Qb3 is a maximally flat alignment that in fact does not exist once the loudspeaker is in the real environment
<snip>


Please explain

Ruediger

[Ian Mackenzie]

I will post a Bassbox simulation soon

[Ian Mackenzie]

Okay

I will try and give you context of using a particular jbl driver designed specifically for a jbl system.

How that was incorporated in the JBL 4365 and relate that to your project

Firstly, The whole TL alignment thing is a continuum of parameters based on electrical filter theory

However, all the simulators assume the driver is in free space ie not in a acoustic space with wall/floor boundaries.

Secondly the simulator does not consider the impact of placing the driver on abaffle of particular dimensions where the baffle will behave as a reflector up to a certain frequency and then a diffuser.

In the context of the JBL 4365 Jerry or who ever designed a driver with a stiff diaphragm and characteristics that would make it suitable for GT to adopt a systems engineered approach to a two way system

They were interested in a woofer that would work in a 2 way system and by manipulating the box tuning in a real room and the Voltage drive to the woofer from the passive crossover this would give a smooth response with reasonable bass extension

How is this possible given your simulator outcomes?

As you have discovered this driver when plugged into a simulator yield a small box and high tuning in the 40's.

In the real world however such a box is not going to deliver any degree of dynamic authority in the bass because it can't below the port tuning frequency

So we make the box bigger and tune the box lower in the region of 30 hertz

The box is now around 150 litres.
In the attached Bassbox simulator graphic you can see two curves

One is the driver as if no room gain existed and the other with addition of room gain

This is ball park of course

The key is the acoustic output in the 30 Hz zone and overall response flatness

In the box itself around 3 Db of sensitivity is shaved of the woofer midband response by the crossover to ensure a smooth response on the baffle

[Ian Mackenzie]

The up shot of this is you have two choices being either un assisted or assisted tuning with boost at the box tuning frequency fb.

Depending on the driver the assisted box volume may be smaller than the unassisted box volume

Assisted alignment are not easy to implement in practice without test equipment and experience

The other consideration the baffle step response of the woofer on your final baffle?

This could be as low as the 150 Hz region where the output of the woofer falls off.

Jbl of course tale this into consideration when they design and voice the system and determine the optimum voltage drives for the crossover network

You may therefore consider a dbx drive rack to enable setup and manipulate the final response of the woofer for your diy project

Good luck

[bubbleboy76]

Thanks Ian!

I have a DBX Driverack 4820 and measuring equipment, so I will try to get it tuned in including the room-gain, in the end. For 5 mic-positions placed in ear-height in a "5 on a dice" manner around the listening-position, averaged. Like G.T has suggested.

[Ian Mackenzie]

Good idea

The sims are fun to play with but don't rely on them in isolation

You want woofer motor delivering real output from the port in the 30/35 region

Going further with critical insights the human ear is acutely sensitive to bass amplitude flatness, extension and low 2nd distortion according to AES publications

If you can get the system outside in your driveway again the garage door it will be much easier to see what the box is doing without too much interference from room modes

Once you get base line eq saved then getting it right inside wil much easier

[bubbleboy76]

hlaari knows how to pack woofers safely :)

[JeffW]

Here's how Harman packs the same driver. There was nothing in the box besides the driver and that sheet of bubble wrap, you can see the outline of the magnet in the side of the box.

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=53680&stc=1&d=1321577148

[Mr. Widget]

Here's how Harman packs the same driver. There was nothing in the box besides the driver and that sheet of bubble wrap, you can see the outline of the magnet in the side of the box.
Not to defend the outrageously poorly packed shipments that have left various warehouses contracted by Harman, they have moved their operations again and terminated their agreement with some of the past warehouse companies that they were subcontracting with.

There have been quite a number of shipping horror stories where Harman products have met terrible ends due to extremely irresponsible packing. That said when I received my DD67000 woofers last year they were very well packaged in custom packing with proper die cut inserts. I hope this is the new normal.

Of course Hlaari's example is not going to be matched by Harman anytime soon. :D


Widget

[hlaari]

I hope at all parts you got from me will work perfectly:)

My s9900 project does not go as good as I was hoping for, I have only got few parts of the s9900 horns:(
this have take a way to long time to get the parts I need for the project so I might sell the parts and the S9900 enclosures

there is possible at I can get a used pair of K2-S9900 for good price or I will go for the 4348 monitors from Japan




hlaari knows how to pack woofers safely :)

[bubbleboy76]

Here's how Harman packs the same driver. There was nothing in the box besides the driver and that sheet of bubble wrap, you can see the outline of the magnet in the side of the box.

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=53680&stc=1&d=1321577148

Are you kidding me?! :(

When buying 2216nd:s from speakerexchange, how is the packing then? Good?

[hsosdrum]

hlaari knows how to pack woofers safely :)

Outstanding! You could use that as the guts of a speaker cabinet (for a much smaller speaker, of course).

[Don C]

When I bought my M2 horns from them, they arrived unbroken. I considered this to be only luck as they were packed with bubble-wrap that looked insufficient to me. And the cardboard box was lightweight.



Are you kidding me?! :(

When buying 2216nd:s from speakerexchange, how is the packing then? Good?

[JeffW]

Are you kidding me?! :(

Not kidding. And I bought a pair of LE14H-3 that came in identical packing, the UPS driver was cradling the box as he was coming up to the door, the driver was hanging out of one box. As Widget pointed out in the thread those pics are from, they were never supposed to sell these 1501FE drivers to me in the first place, so I guess they didn't need to give much thought to packing.


When buying 2216nd:s from speakerexchange, how is the packing then? Good?

Never bought from them, but I don't see how they could be worse.

[bubbleboy76]

I have done some more design-changes lately.

I want to use the original 4365 speaker grilles that I have, due to wild and naughty kids. Hence, the front baffle must be 547mm wide.

I also want 140L internal volume, for a M2-like tuning (and possibility to use M2 components down the road).

I want to be able to place the speaker deep in a corner, and be able to dock damping to the sides.

I added details about bracing as well, the green dotted lines.

This is the final design, I think!

It looks very wide on the drawing, but I have tried it on a paper-model of the footprint, and it is a keeper.

Friends, speak now, or forever hold your peace! ;)

Flodstroem (or someone else), I would be very grateful if you could confirm the theoretical length and optimal placement of the BR-ports again regarding standing waves etc, with your software.

I would be very grateful for any other comments and feedback now, both negative and positive, before I send this to production.

[bubbleboy76]

The paper-model of the box footprint resembles an Manta-ray. Maybe, I should change name on this project :)

[cooky1257]

The paper-model of the box footprint resembles an Manta-ray. Maybe, I should change name on this project :)

Well you did ask.....I would just consider losing the L/R shoulders-you wont lose corner placement/triangular backside but will gain a more elegant frontal aspect when you consider the horn sitting on top(in either orientation)I've tried the H9800 horn vertically and ended up going back to horizontal as the preferred option.I'd also place the ports further apart so their outside edges line up with the edges of your driver.

[bubbleboy76]

Well you did ask.....I would just consider losing the L/R shoulders-you wont lose corner placement/triangular backside but will gain a more elegant frontal aspect when you consider the horn sitting on top(in either orientation)I've tried the H9800 horn vertically and ended up going back to horizontal as the preferred option.I'd also place the ports further apart so their outside edges line up with the edges of your driver.

Thanks for your feedback.

The shoulders was originally added because I needed to fit the driver depth (when I had smaller dimensions). But I kind of like it. But I see what you mean, they look too wide.
If I do it like an triangle with 547mm hypotenuse/front baffle, I get too small internal volume (45L).

The ports further apart, is it estetic, or functional regard? It is tight space to the back-wall (depending on port-length), that is why they are so close togheter. I can not have them vertically centered above each other, because the grille is only 700mm high, won't cover woofer and ports.

Some more details added about damping, and placed the ports a little bit differently.

[bubbleboy76]

I am starting to get weight anxiety, this thing will be too heavy probably :(

It is really hard to get all parameters the way you want them, I have learned so far.

One of my starting parameters was to break up the 4365 into smaller parts, to reduce the weight. 4365 was too heavy to carry up may stairs.

[cooky1257]

I am starting to get weight anxiety, this thing will be too heavy probably :(

It is really hard to get all parameters the way you want them, I have learned so far.

One of my starting parameters was to break up the 4365 into smaller parts, to reduce the weight. 4365 was too heavy to carry up may stairs.

Guestimate here; If you were to make the rear corner a right angle you'd recover the vol from the loss of one side shoulder and if you increase the front to back distance by 40mm you'd be pretty much good to go-spaced out ports n all...Google sketch-up is an easy and fun way to mock up some 3d ideas..

[Don C]

Google sketch-up is an easy and fun way to mock up some 3d ideas..
I couldn't disagree more. A very steep learning curve there.

[bubbleboy76]

I have tried sketch-up 2 times, and I lost the will to live both times!
I have an M.Sc in computer science, and I work with usability of systems.
Sketch-up is over my head. There is probably some hidden cognitive code that needs to be broken before understanding that thing.

[cooky1257]

I have tried sketch-up 2 times, and I lost the will to live both times!
I have an M.Sc in computer science, and I work with usability of systems.
Sketch-up is over my head. There is probably some hidden cognitive code that needs to be broken before understanding that thing.

First create a rectangle(550x550), then push/extrude that into a block(838mm tall) then use the line tool to mark off the top/plan and the push tool to chop away the bits you dont want-think removal of material like a sculptor.

[bubbleboy76]

Kebnekaise 2.5

[more10]

I have tried sketch-up 2 times, and I lost the will to live both times!
I have an M.Sc in computer science, and I work with usability of systems.
Sketch-up is over my head. There is probably some hidden cognitive code that needs to be broken before understanding that thing.

I share your experience. It is completely not logical :-)

I use FreeCAD. It is programmable in python. I use the linux nighty builds in order to help find the bugs.

[cooky1257]

....I would just consider losing the L/R shoulders-you wont lose corner placement/triangular backside but will gain a more elegant frontal aspect when you consider the horn sitting on top(in either orientation)I've tried the H9800 horn vertically and ended up going back to horizontal as the preferred option.I'd also place the ports further apart so their outside edges line up with the edges of your driver.

Gives you an idea of proportions...

https://c1.staticflickr.com/5/4239/34535892744_f47539a933_z.jpg

https://c1.staticflickr.com/5/4209/35212208252_7f4c9f1a8f_z.jpg

[1audiohack]

Kebnekaise 2.5

I like it! I am a two woofer kinda guy. 3.5 way or different sub?

Barry.

[bubbleboy76]

I like it! I am a two woofer kinda guy. 3.5 way or different sub?

Barry.

2.5 way. No sub, and no UHF, for now.

Anyone who knows how exactly the ".5" augmenting woofer in the Everest2 is setuped crossover-wise (acoustically)? Where it overlaps the other woofer, and how it rolls off.

Edit: Found some slopes here, but I do not know if it is electrical or acoustical target curves:
http://www.audioheritage.org/vbulletin/showthread.php?29853-h66000-h9900-h4365&p=301424&viewfull=1#post301424

[bubbleboy76]

Looks like an 6dB/oct rollof starting at 80Hz in the Everest2.

Page 15 here:
http://www.jblsynthesis.com/tl_files/catalog//jblsynthesis/Everest%20DD67000/JBL%20Everest%20DD67000%20and%20DD65000%20Owner%27 s%20Manual.pdf

[bubbleboy76]

First create a rectangle(550x550), then push/extrude that into a block(838mm tall) then use the line tool to mark off the top/plan and the push tool to chop away the bits you dont want-think removal of material like a sculptor.

I got kind of that far. It is when trying to change things I get lost.

[1audiohack]

Looking at the measured response for the Lf woofer and its little board with two coils and caps makes me wonder.

I haven't looked for the component values yet but there is more to it than a coil.

Barry.

[bubbleboy76]

Maybe it is a kind of first-order Chebyschev-like electrical slope on LF1 in the Everest2?
Resulting in a first-order Bessel-like acoustical slope for LF1, with a bump down low compared to LF2.

[bubbleboy76]

Gives you an idea of proportions...

https://c1.staticflickr.com/5/4239/34535892744_f47539a933_z.jpg

https://c1.staticflickr.com/5/4209/35212208252_7f4c9f1a8f_z.jpg

Thanks!

[bubbleboy76]

Current state of affairs.

[bubbleboy76]

I have sold the DBX4820, and I will use a BSS BLU-160 instead. The BSS is more flexible, and has in practice an unlimited number of PEQs to use per channel.

I have drycoded some initial settings for now, based on the ones I had for my active 4365.

[1audiohack]

Looking good!

Barry.

[bubbleboy76]

Looking good!

Barry.

Thanks :)

[bubbleboy76]

Finally, the build has started :)

Here you can see 3 sheets of 2x12mm mdf being glued with damping glue.

[bubbleboy76]

This is exactly how each LF-box will look like.

[1audiohack]

Is that a jack screw to press against the motor back plate?

Barry.

[bubbleboy76]

Yes.

It will also make it possible to connect to the back-wall, if I should want so in the future, to reduce rocking.

The boxes will have weightadjusted soft decoupling feet (I have hard floating wood floor).

Inside it is a 31mm diameter "machine foot" pressing against the element back. There is 51mm free radius on the back of the element, so it will not disturb the ventilation holes.

[bubbleboy76]

The carpenter says he is very impressed how dead / non-resonant the constrained layer damping makes the mdf, when knocking on them.

[bubbleboy76]

Some progress.

[bubbleboy76]

Theory and practice.

[1audiohack]

That's super cool!!!

Barry.

[bubbleboy76]

The LF-boxes are finished now and painted! I will fetch them at the carpenter next week.
HF-boxes for the horns will be built next.

[berga12]

interesting build :)

you should replicate a Wood horn and not a plastic one :)

engage your 3D and CNC skills!

[bubbleboy76]

I should engage my molding skills. I want the horn in concrete like K2 S9500.

[berga12]

WOW!!! nice project!

[bubbleboy76]

Some delay at the painter, but now the LF-boxes are painted. Will fetch them this coming Saturday.

[baldrick]

Looks great!

But the boxes looks small for 1501FE? No vents?

[bubbleboy76]

It is ~50L net volume closed boxes that will be around 80% filled with damping, and have linkwitz-transform-ish digital correction (in conjunction with the room and corner gain).
Dual woofers per speaker, and most likely placed with significant corner and room gain.

~50L is also the kind of optimal theoretical box-size according to Ruedinger in this thread, with regard to suitable Thiele alignements for 1501fe. So I can add ports later. But it is not very likely. More likely they will have to serve as closed corner-subs, if this project do not work out for some reason. JBL TiK-sub works niceley closed with this size box.
Another option might also be to add a third and fourth woofer/box per speaker, hahaha :)

When I simulated closed box for 1501fe, box sixe 40L, 50L or 60L did not make a large difference, for the SPL-curve at least.

Basically, I choosed dual woofers in closed boxes over single woofer in larger ported box. My main design constraint is currently the allowed total speaker size. But with this modular approach my solution is scalable for the future.

[bubbleboy76]

Not visible, but there are magnets inside the front baffle, for the speaker grille.

[bubbleboy76]

The eagles has landed!

Now waiting for the horn-boxes.

[bubbleboy76]

More pics.

The boxes are filled to approx 70% with a combination of sheep-wool based dampingmaterial and bed-mattress foam (do not know correct english word).

[pos]

Those look great and well integrated!
I bet you already started listening without horns :D

Is that mattress foam you are using of open-cell type ?

[bubbleboy76]

Those look great and well integrated!
I bet you already started listening without horns :D

Is that mattress foam you are using of open-cell type ?

No listening yet. Will do the speakon speaker-cables today (using Canare 4S11-cable).

I will use the LSR305:s as tops, until I get the horns (just some temporary textbook electrical LR24 crossover at 80Hz is my plan).

Don't know about the foam. I was recommended this mattress by speaker-people in Sweden that has measured it in closed boxes, and compared it to other damping materials.
It is this one:
https://jysk.se/sovrum/madrasser/skummadrasser/basic/skummadrass-70x190-basic-f10#store_stock

It comes compressed, and kind of expands over the course of 2 days. So it sets itself a little bit tighter inside the box, I think.

[ivica]

...
Don't know about the foam. I was recommended this mattress by speaker-people in Sweden that has measured it in closed boxes, and compared it to other damping materials.
It is this one:
https://jysk.se/sovrum/madrasser/skummadrasser/basic/skummadrass-70x190-basic-f10#store_stock

It comes compressed, and kind of expands over the course of 2 days. So it sets itself a little bit tighter inside the box, I think.

Hi
Comparison between the diffuse field sound absorption coefficients of:
sheep wool sample S4,
mineral wool,
recycled polyurethane foam and
polyester fibers (PET).



https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5706224/figure/materials-10-01277-f007/

regards

ivica

[bubbleboy76]

Hi
Comparison between the diffuse field sound absorption coefficients of:
sheep wool sample S4,
mineral wool,
recycled polyurethane foam and
polyester fibers (PET).



https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5706224/figure/materials-10-01277-f007/

regards

ivica

I have seen something like this before, a combination of sheep wool and foam seems to be good for
my box inteded range (20-650Hz).
someone told me that it is best to have sheep wool closest to the element.

[bubbleboy76]

Horn box design.

The bottom will be openable with a lid.

I have left the idea of enabling a vertical horn position. But, the box will be able to be put in the middle between the LF-boxes, if I would want an MTM-topology later in life.

[bubbleboy76]

Work in progress.

[pos]

The black and white contrast will certainly look nice on that one!

[bubbleboy76]

The plan was to paint it all white.
But now you make me hesitate.

[1audiohack]

That is stellar work! Very nice.

Barry.

[bubbleboy76]

Adding bat-slayers to the mix.
Bought a pair of 045be from ebay. Thanks Johanwholst for the tip!
I hope they work....

From this graph it seem they will not need much dsp when used 10-20KHz.

There will be comb-filtering with the crossover to HF horn with 476mg. Maybe very steep slope would be applicable here? I have FIR-capability, so I can do very steep, if I want.

My HF horn/driver beaming starts at 8KHz. So the plan is to crossover at 8-10Khz somewhere.

[johanwholst]

Testing mine at down to 10k as we speak. They do a fine job down there with a steep crossover

Hope they arrive in good shape. Im sure you will like them

[bubbleboy76]

What is the lowest frequency a JBL 476mg compression-driver can play safely, without risk of damaging it long-term? Let's assume a 48dB/oct high-pass filter, and "normal" home-listening levels. And H4365 horn-loading.
Anyone?

[bubbleboy76]

Testing mine at down to 10k as we speak. They do a fine job down there with a steep crossover

Hope they arrive in good shape. Im sure you will like them

Have you tried even lower crossover with your 045be-1? I am thinking about 8K crossover, because it is there the beaming starts on my LF-horn. And the distortion is lower in that area for 045be than 476mg, according to the specs.

[bubbleboy76]

It went white. Like the top of mountain Kebnekaise.

[johanwholst]

Have you tried even lower crossover with your 045be-1? I am thinking about 8K crossover, because it is there the beaming starts on my LF-horn. And the distortion is lower in that area for 045be than 476mg, according to the specs.

I have been testing out different xo lately and use it from 10k now. This is the lowest i tried them. No reason to go lower with 2384 but you must use your ears to judge with your midhorn.
I Like your paintjob!

[johanwholst]

Btw did your 045be arrive safely?

[bubbleboy76]

Btw did your 045be arrive safely?

Yes they arrived safely, and they look much better than the pictures looked like.
I hope distortion-measurement looks nice as well later on....

[johanwholst]

Im glad to hear that! It was a sweet deal

[bubbleboy76]

Yes!

[bubbleboy76]

Oh yes.

[bubbleboy76]

Quote from my friend:
Why do not JBL make them like this? They would sell thousands!

So JBL, feel free to contact me if you want to sell thousands of this model. Just give the contributors this thread a set of nice top-shelf drivers, and you are good to go ;)

[Odd]

Quote from my friend:
Why do not JBL make them like this? They would sell thousands!

So JBL, feel free to contact me if you want to sell thousands of this model. Just give the contributors this thread a set of nice top-shelf drivers, and you are good to go ;)

I would think JBL is waiting for your measurements before they contact.
We others are waiting too.

Very well done project.

[bubbleboy76]

I would think JBL is waiting for your measurements before they contact.
We others are waiting too.

Very well done project.

Yeah now the fun begins. I am not so interested in the hardware actually, more the software. But I had to put a year on hardware first, as it turned out.

[pos]

Looking good :coolness:

[bubbleboy76]

Quick-and-dirty measurements of the woofer boxes.

No EQ filters. 1/24 smoothing.

The speakers not fully inserted in the corner yet, and without the damping I will have later between speakers and wall.

I see that the dual vertical woofers seems to nicely cancel out a lot of each-other's SBIR (from floor and roof mainly, I guess) .

I also see that my room front corners do not behave the same acoustically (different kind of walls). Larger "corner-problems" on Left speaker. That corner is concrete walls. The other corner is wood/plaster. I maybe will have to make separate EQ-settings per speaker. Or maybe it is good with different LF behaviour from L and R down low, to smooth things out in total?

(Note, the dB-level was not calibrated in REW. It was higher than shown in the graphs.)

[hlaari]

Great to see at you finish your project:)
the enclosure are very well made





Ari

[bubbleboy76]

Small steps ahead. Cloth on the grilles.
I will add another layer, so the woofers are not shining through. I will try to find a better color-matched white cloth.
It's all white because I want the speakers to blend in with the walls (for them to disappear as much as possible).

[bubbleboy76]

Damping/support between speaker and wall.

The speaker will now be pushed in as deep as possible into the corner. This will push the SBIR cancellations from the walls behind the speaker up in frequency. Hopefully up into an range where the speaker is more directive, and where resistive damping has more effect.

(In a future dedicated room, the cabinet shape enables me to dock 12cm resistive damping to the sides, to reduce the harmful side-wall early reflections. Current room and current wife does not enable this though!)

Next step: a lot of measurements.

[bubbleboy76]

Another thing, it has started to sound pretty good as well! I really believe this stuff has quite some burn-in time, especially for me that can not play so loud in an apartment.

[bubbleboy76]

One of the JBL 045Be drivers I bought on ebay is bad.
See comparison with the good one. Measured from 10cm, with 3 cycles frequency dependent window.
Big suckout 4000Hz-7500Hz.
I had them cleaned magnet gap and cleaned membrane and installed properly centered in the horn with the correct screws by a speaker repair-firm. But still same problem.
Don't know if it matters for use 10KHz-20KHz though?

Anyone having a single 045Be to sell?

[ivica]

One of the JBL 045Be drivers I bought on ebay is bad.
See comparison with the good one. Measured from 10cm, with 3 cycles frequency dependent window.
Big suckout 4000Hz-7500Hz.
I had them cleaned magnet gap and cleaned membrane and installed properly centered in the horn with the correct screws by a speaker repair-firm. But still same problem.
Don't know if it matters for use 10KHz-20KHz though?

Anyone having a single 045Be to sell?

Hi bubbleboy76,

Did You check phase plug proper gluing , as I have seen on some JBL older drivers 2447, and 2451, that central part of phase plug can be moved due to the bad glue used.
Another experiment can be made, some paper 'shims' put under the diaphragm mounting ring in order to make some distances between the diahragm and the phase plug (just for an experiment).
Check with lower frequency tone of a kind of a buzzing noise can be hear due to mechanical diaphragm&VC assembly touching with the driver&phase-plug assembly.
Is there any diaphragm 'fracture' or VC bad gluing to the diaphragm.

I wish You to overcome the problem.

regards
ivica

[bubbleboy76]

If the driver is bad, but the membrane is ok, could I then fit my beryllium membranes into 045Ti drivers?

[pos]

Have you tried swapping diaphragms and cores?
How do the harmonic and intermodulation distortion measurements look?

[dn92]

It looks exactly as a not well centered JBL diaphragm. On the measurements you should also see distorsion in the problematic frequency area.

My experience in changing 2" JBL diaphragms (I experienced similar frequency responses problems) is that it was very sensitive in terms of centering them.
Use a generator and a mike, focussing in the frequency range not only the ear (except if you're a golden ear), try small movements or other fixing positions. This might be a bit stressing with Be I recognise.
as you have a reference unit working well you can also use impedance measurements trying to match the correct unit.

[bubbleboy76]

The right one is my bad membrane compared to a new one (another model).
This is after extensive cleaning. Looks like shit.
They tell me the core is OK, but the membrane is not OK.

[bubbleboy76]

Measurements from today comparing my drivers.
I am worried about my left 476Mg as well. Too high distortion?
(1m to mic. In middle of room with 3 cycles FDW)

[bubbleboy76]

continued...

[alpina]

Very beautiful. My congratulations

[bubbleboy76]

Off-axis measurements.

NB, there is a -9dB autoformer on UHF (because I will use the THX AAA headphone amp later).

[bubbleboy76]

Pics from measuring yesterday.

[bubbleboy76]

A distinguished member of this forum noticed that it is a 4” membrane on the picture. The service guy has worked in the wrong driver, it is confirmed now.

[martin_wu99]

So beautiful,great job!:applaud:but why not Kebnekaise S4367? i like 4367:D

[bubbleboy76]

So beautiful,great job!:applaud:but why not Kebnekaise S4367? i like 4367:D

It was 4365-parts I had the opportunity to buy.

[martin_wu99]

It was 4365-parts I had the opportunity to buy.
I can't believe that you have made it , are you a carpenter?:D

[bubbleboy76]

I can't believe that you have made it , are you a carpenter?:D

A carpenter made the boxes for me, but it is my own design.

[bubbleboy76]

Sweet music is playing.

[Robh3606]

Nice! They look great.

Rob:)

[Earl K]

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=82885&stc=1&d=1543676640

Beautiful!

Nice View!

Is that a Hagstrom hanging on the wall ?

:)

[bubbleboy76]

Thanks!

The guitar is nothing fancy. It is a DeArmond M-75T Champagne Sparkle.

[martin_wu99]

So beautiful:applaud: seems you have a telescope,what do you observe?:blink:

[bubbleboy76]

I watch the ocean to read my volume setting, judging the size of the small tsunamis produced by the quadruple 15" woofers!

[johanwholst]

Great work on your monitors!!!

Did you sort out your issues with the 045be driver that measured strangely?
Also, did you settle on a crossover frequency for the UHF drivers?

Johan

[bubbleboy76]

One of my UHF-drivers still have an issue at 6k-8k. My service-guys tried to fix it, but did not succed.
I crossover HF/UHF 96dB/oct Linkwitz Riley at 10KHz. I hope this avoids that problem mostly.
I would like to try crossover at 8k someday, but then I need a new UHF-driver.

[martin_wu99]

One of my UHF-drivers still have an issue at 6k-8k. My service-guys tried to fix it, but did not succed.
I crossover HF/UHF 96dB/oct Linkwitz Riley at 10KHz. I hope this avoids that problem mostly.
I would like to try crossover at 8k someday, but then I need a new UHF-driver.
why not go active?

[pos]

I'd say bubbleboy76 is already pretty active on the forum.

[bubbleboy76]

why not go active?

My wife also tells me that all the time. Yeah, I should probably do that!

[martin_wu99]

I'd say bubbleboy76 is already pretty active on the forum.
Absolutely!

[martin_wu99]

My wife also tells me that all the time. Yeah, I should probably do that!
Is your wife also a audiophile?:applaud:;)