folkdeath95

Dynamat and materials like that are meant to damp vibrations/resonances in metal car body panels. They can also be helpful with metal horns like K400s, but wooden panels already have more inherent damping than metal panels, so the benefits of applying it would be limited. I use the word "Dynamat" as a generic term. I'm not sure I will use this stuff. Bitumen sheets or material used in house buildind to damp walls or wooden doors could be interesting. I have some scrap of Dynamat, I will try it on some plywood board to see how it manage with vibrations. I already replaced the back panel with a thicker one (19mm plywood). I can feel the difference when I put my hand on it. And I can hear it with a clearer, less draft (I'm not sure of the word) bass sound. A definitely essential mod.

Thanks for your answers. Stiffening the walls seems to be a good idea. It must be worth the work. Nevertheless, I think that stiffening a cabinet can move parasitical vibrations to an upper frequencies, so maybe it could be usefull to put Dynamat after the bracing the enclosure. Your idea seems logical, as in a closed enclosure, the rear wave of the speakers has to be totally absorbed (and this how most closed speakers are made). But it seems that lots of people who tried this on their Heresy didn't like the result. So I'm quite hesitant. Did you stuff your cabinet with polyfill?

Hello, A lot of posts have been written about damping the Heresy's cabinet and it seems that almost everybody consider it as a bad thing. But all those experience were an attempt to damp the load of the woofer. I recently read a very interesting article about parasitic vibrations in speakers enclosures and I'm thinking about damping the cabinet walls (maybe with Dynamat or bitumen sheets). I already replaced the back wall with thicker plywood with good results, so I'm wondering if damping the walls could be as good. Does anybody here tried such a mod?

Your experience seems to prove one thing: theory is one thing, pratice is another. Inductor's sound is not just a matter of DCR. Air core inductors are onften prefered even if they have higher DCR. Crossover design is an hard thing and requires lots of tests that can somtimes be disappointing. Let's hope you can have a refound and continue your work on your Heresy.

Yes, you can sand your cabinets. When I bought mine, they were painted in green. I first had to scour them before sanding using an orbital sander. I used 80, 120 and 180 sanding paper and I didn't ruin the veneer. I also replace the back panel with and thicker one (18mm plywood) with banana plugs. I unglued the original sticker by the back panels over a pan filled with boiling water on my hob. The "cooking"[] takes approximately 15 minutes before the stickers started to unglue, then I gently peeled it from the wood.

I think the difference will be very, very small. When I was working on my Heresy, I measured the K22 with and without the crossover (I used a Behringer ECM8000 and the software used was Arta). IIRC, there was no visible differences between the two curves in the low end (before the inductor starts to act as a crossover). I haven't try to zoom on the two curves to see if there was any differences (but I could try when I'm back at home). But, theoritically, given that the K22 is less efficient that the other drivers, any small fraction of dB won by diminishing the inductor DCR can be considered as a good thing.

It seems that your crossover is a type E2. It could explain why I was a little lost when you talked about this 33µF capacitors that mine doesn't have. I thought the Type E2 was made for Heresy II, but it seems that I was wrong and that this crossover was used on Heresy I.

Hi Antone, I'm a little lost with all your crossover modifications. No offense to you, I think it's mainly because of my english skill. Could you please post a drawing of your new crossovers (maybe by modififying the Type E drawing that can be found here. Thanks.[]

On the simulations with WinISD, the K22 goes to 63Hz at -3dB, the Dayton goes to 60Hz. I don't know how deep goes the Crites, but in a Heresy cab, when trying to keep good efficiency in mind, it's hard to go deep (the best result I had on WinISD was 55Hz at -3dB with a Focal Audiom 12, but the Heresy needed to be trnasformed in a bass-reflex enclosure). If just looking the lowest frequency at -3dB, the Dayton could be considered as an improvement, even if I don't believe this 3 little Hz can be considered as an indication of sound quality.

Well, the curves I posted are only simulations made by a software using the Thiele/Small parameters of the drivers. Moreover, the volume of the box is only an approximation. I measured my Heresy to calculate the internal volume and found 54.5L. I wish to consider the volume of the braces, speakers, horns and crossover but I was to lazy to calculate it, so I set the volume at 50L in the software. I don't if this is more or less than the real internal volume of my cabinets. My curves are certainly not as accurate as measurements in a anechoid room, but it's a good way to make some comparisons.

Thanks for the informations, parts ref, etc... I made some quick simulations of the Dayton woofer with WinISD. It allows the Heresy to go a little deeper: 60Hz at -3dB versus 63Hz. The efficiciency is lower than the K22, did you attenuate the squawker and the tweeter to match the woofer SPL?

That looks pretty interesting. Do you have any clues to help us better understanding your work? Which woofer did you choose? Could you draw a schem of your crossover? Thanks.[]

Thanks.[]

With the swanping resistor, changing the position of the driver on the T2A doesn't affect the impedance seen by the amplifier, so the value of the capacitor can stay nearly the same. With the squawker back to stock position, the midrange is not too bright (to my ears). Only the trebble need to be attenuated. When plugged on tap 2 (with the squawker) it's OK, but I'm not sure it's safe to have two drivers plugged on the same tap (that was my main question). Thanks to both of you for your answers.

Sorry if I haven't been clear. The midrange is already back to stock position (tap 2) and I'm still trying to attenuate the tweeter. That's why I thought about pluging it on the tap 2 too. What will be the goal of the resistor in parallel with the tweeter?

Nobody have an answer?

Hello, Like many people here, I found my Heresy rather on the "treble side". I discovered on this forum that the Type E crossover could be modified to change this. So I decided to try this mod: The result was a "smoother", more quiet treble, as I expected, but I found that the squawker was attenuated too much. So I thought about pluging the squawker back on tap 2. But, there will be two drivers connected on this tap and I don't know if the T2A can work like this... Hence this question: Is it possible to connect two drivers on the same tap of a T2A? Thanks.

Thank you everybody for your very comprehensive answers.

I totally agree with you. But the formulas are good starting points, I think. Every art has its basics.[]

I've never heard of that before. From what I read, I thought the voice coil inductance wasn't included in the crossover calculation. On every source, the formula was: L=Z/(2*PI*Fc). From what you say, it should be read as L=(Z/(2*PI*Fc))-Le, right?

Yes, you're right, the measurement was made with the driver in the box (only the crossover was missing).

I didn't know that. I must confess I only studied the Type E crossover as my Heresy are my first Klipsch speakers. So I didn't point the similarities in crossover components. That's a very interesting information. (It could explain why so many KHorn users tweak their crossovers or the crossover upgrades like Al K's offers..) Maybe a little work on the Type E could give good results too...

Excuse my ignorance: which fact are you talking about?

Hello, Does anybody has ever seen the K22 impedance curve? The Type E crossover frequency for the woofer is said to be 700Hz and, so it seems that the 2.5mH self has been calculated for a 11 Ohms impedance. But I mesured my two K22 with Limp and the results are a little disturbing.Here is the curve of one of them (the second one is very close): At 700Hz, the impedance is close to 17 Ohms, so it should need a 3.9mH self... Can the age of my speakers (30 years) explain such a difference with the theorical impedance value? I've looked for a K22 datasheet with an impedance curve, but I didn't manage to find one.... Does anybody has any clues? Thanks a lot.

Thanks. Things become clearer in my head.