Questions for my Khancenter build (padding/stuffing and crossover placement)

[zjeff222]

I chose the Khans for my HT system. I'll start with the center because my current one is tiny while my current towers are, well, towers I already built a subwoofer box but I have no experience with loudspeakers.

I only have a few questions left.

1. Padding/stuffing: which surface should I pad, and/or which chamber should I stuff? I guess stuffing is easy to try but padding is not easy to change once the speaker is built. I'm not even sure I would know what to listen to make adjustments. So what do you guys do?

2. Crossover placement/fixation: I plan on having 3 boards fixed on the back walls. This would place them directly behind the drivers, so I'm not sure it's a good idea if the enclosure is padded and not stuffed. I chose this placement base on accessibility and induction between coils (crosstalk). So what would be the best placement?

[dar47]

Nice model. :T

I have tried, foam, rockwool and pink insulation, as well as 1/2" rigid insulation but I think I like the a short broadloom rug the best for ease of use and sound. Just buy a 5' x7' area rug at HD, $30. I line all surfaces except the bracing and the back of the front baffle. The mid chamber I use 1/2" rigid yellow insulation and carpet in front of that only on the mid chamber back wall to absorb the mid driver back wave. Cheap way of getting the 1/2" yellow rigid insulation is from those suspended ceiling tiles with the white vinyl layer over the yellow ridged isolation, just tear the vinyl off . You usually can buy just 1-2'X4' panel not a hole box at HD. All is glued on with simple hot glue, or PL Premium (usually have a extra tube lying around). :B

Your mid xover board should be put at the back not in the mid chamber, just run sealed wire into the mid chamber. I like to try and keep the boards not directly behind the drivers if possible.

Here is my current center,

[cjd]

I really like the 3 layer Sonic Barrier from PE. I use it on the walls adjacent to the drivers, and for something like the mid in this design, I also would place it behind the driver. Its most important role is managing reflections, but damping panel resonance is also quite good - combined with my excessive bracing I get very inert boxes. The thinner 3 layer is plenty. Keep an eye on magnet spacing and be sure to maintain airflow around the driver, especially on the mid. It's a bit snug, and any wall lining may not be able to go all the way up to the baffle.

In your box, I might stuff the back of the woofer chamber (behind the braces) and line just the front half; I'd start with just a handful of stuffing on the mid.

If you put the mid/tweet crossover in the mid box, I'd see if you can keep it behind the tweeter, so that directly behind the mid is some wall lining. You can then wedge a bit of stuffing between the crossover board and the tweeter back, so only the top 1/3-ish lightly stuffed that way.

C

[zjeff222]

Thanks for your replies! For now I'm having fun with sketchup - I'm waiting to have free time during the day.

So my obvious problem is the lack of depth of my box. Stuffing the back part is to allow me to keep the boards behind the drivers right? Is this a big compromise?

Also, do I need specialized stuffing or is it basically the same as cushion stuffing? (I have some of that already)

And, what is the best way to attach the boards to the box walls? (so that they can be easily removed and placed back from the driver openings)

Finally, is it worth the trouble designing everything so that the crossover can be serviced?

thanks again

[---k---]

I used a combination of rigid insulation and single layer Sonic Barrier (The thick, but cheaper stuff) on the walls of mine. I didn't stuff them beyond this. Whether you need to stuff or not is probably dependent on what you use on the walls and your preference. I suggest using Sonic Barrier on the walls like CJD suggested. Then, get some a small bag of pillow stuffing, or R13 pink fiberglass insulation, or Acoustic Stuff (order of worse to best, but such small differences I wouldn't worry about it.) and play with it. The process I've read many people use is to stuff it fairly full, then listen, then remove some, then listen, the remove some more. If you use the sonic barrier, I'm guessing you'd need no more than two fistfulls for each driver. You can also use a Woofer Tester to measure the impedance to find the too much point.

My crossovers are right behind the drivers. I;m sure it is better to have the crossovers away from the drivers, but that is a last 1% type of thing. I'm not worried about it. Maybe if I was building Jon's Ardents, I would be more concerned. If you can move them behind the mid chamber, great. If not, not worth loosing sleep over.

I've used heavy duty velcro to hold my crossovers. Works very well. Zip ties through holes in the cross over bracing works too.

I would definitely make it so you can get to the crossover after completing. I don't think you'll need to service them, but who knows.... No good can come from making them in accessible. Murphy's laws and such.