my house is too small for that behemoth.

I've got a 15" sub in a tiny box with a linkwitz transform circuit so it plays down into the low 20 Hz anechoic. it's the bomb. and plenty loud for my dinky house. sounds astounding when movies have planes taking off. feels like you're on the plane.

it's so pimp, even the cats hang.

https://www.miataturbo.net/forum/att...1&d=1261495179

I've heard it, it's alright I guess. :)

I have heard of that trick before. Unfortunately my placement options are somewhat limited :)

OK I see what that is, thanks.

So speaking of floor mount treatments, what is the deal with spikes? I see them on subs, and hear how they are a must, but need to read up on them some more.

Very cool. I have seen linkwitz circuits talked about in the better DIY audio forums but have yet to try them out. That lets you use a small box but still have a low-Q response right?
I have not done much crossover tuning. This one is running off of the LPF on the receiver. Right now it is set for 120 Hz but I do not know what the slope is.

If we're whipping them out, I have one of these in 15" in the theater
Velodyne
It's pretty amazing.

And this guy in the living room
RSW-12 Subwoofer - Specifications

And some cheap Jamo subs in the office and the master.

Yah not only do room treatments matter but speaker placement is also critical. It may nto be necessary to cover the whole front in draping-- putting absorption where early reflections are and standing waves can help clean a room up without making it dead. Personally, I prefer to use broadband absorbers that are heavy on the bass absorption.

I recommend zero auralex products. They are overpriced and a foamed up room will sound like shit. Google owens corning 703 or 705 bass traps. You can DIY them or buy them or buy mine :) 703/705 on it's own has superior broadband absorption characteristics to foam. If you want to decouple your speakers, you can also just use styrofoam boards, or my favorites- mousepads. Decoupling does work some of the time but some of the time it can make things sound worse-- you will have to listen.

I've never heard of these linkwitz circuits before but I don't know speakers very well. If anyone local wants to buy some discount bass traps I have a lot of them that I'm not using now. :)

Tex,
Small footprint enclosures have spikes to add stability. That's obviously not what we're talking about here.
Large footprint enclosures use spikes to decouple them from the floor. The surface the speaker enclosure is contacting of becomes part of the enclosure. When you decouple the speaker from the surface, you will reduce the transmissions between the speaker and the surface. Some people will place brass spikes under the speaker enclosure, then rubber or solid discs under the spikes. A friend of mine in pro-audio turned me onto the Aurulex line, and now I use their products all the time. Previously, my least expensive consumer line I was using was Kinetics Noise Control.

fae-I think you need to take a closer look at the auralex line. They sell more than plain foam absorbers and diffusers. DIY wrapped owens corning boards might cost less, but not everyone wants to go that route. Not to mention, styrofoam blocks under your speaker cabs just looks ghetto as shit. MoPads list under $30 and won't offend the ladies.

http://www.auralex.com/sound_absorpt...nosuede/S3.jpghttp://www.bhphotovideo.com/images/i...345/619652.jpghttp://images.digitalmedianet.com/20...ry/mpad250.jpg

the L-T allows you to "pick" your Q and F3 and give any sub those values in any box. It's pretty awesome. I just built the circuit into the back of a plate amp. only drawback is that excursion requirements go up fast for small boxes, so you can't always play really low really loud. but I'd rather have 2 or 3 mini subs that go to 20 Hz than one that wont fit in my living room.

btw, total cost to build mine was like $400 all told. about half and half sub and amp and the rest in wood and spikes.

Their pro panels do have good specs and their partscience products also look good. Their construction products also look good and their u-boats might be easier to install than rubber disc isolators. There are just other products out there that are as good or better for cheaper. IMO they still do most of their business unethicallly- selling very profitable foam as a panacea.

You are right that DIY bass traps are not for everyone. I've made them before and unless you're a good craftsman (not me- see my frame rail for proof) they may not turn out that well.

I recommend

DIY Bass Traps: Complete Do-It-Yourself Kits : Ready Acoustics!, Hear - Sound - Better

and

RealTraps - Home

Real traps are higher quality but they're more $$.

Y8s did you study room acoustics in school or mostly speaker design?

Mousepads FTW :p The mopad speaker angling thing is pretty slick though. In general, you don't want your head to be off axis from your speakers.

I could't bring myself to buy Auralex stuff. They want ridiculous prices for some of their stuff. Especially the MoPad's, anyone could find material at a store like Home Depot for probably 1/10 of the cost and have the same thing. Buy some dense foam, shape it into a wedge, cover it with cloth for a fancier finish if you like... speaker isolation for a few bucks.

I took one grad level acoustics class. after that it was all self-taught. I did get to meet Siegfried Linkwitz though.

http://home.pacbell.net/donwm/Entry-2022.jpg

I like the chameleon panel approach. I built some simple versions of those, albeit with poly fiberfill, and hung them on the walls in my very noisy living room. The reverberation was so bad that someone that was 20 feet away in the kitchen (open floor plan) had unintelligible speech. The panels made a big difference and they look nice.

Some floor standing room divider walls with some of that corning stuff in the center, trimmed with nice wood, and covered with nice fabric would be easy to build and would look nice. I could hang a long, narrow one from the ceiling in front of the sub and kill two birds with one stone so to speak.

Holy hell I keep forgetting how expensive audiophile stuff is. I am in the wrong business.

So what kind of stuff can one get in the insulation section at Lowe's or HD that is 'close enough' to the Corning semirigid panels? Seems like non-backed fiberglass battens for between wall studs would work well too.

Not sure specifically, but I know out of all of that junk they have to have something that would be similar or even better. I would love to build some of those traps with the wood frame, Corning stuff and the fabric, but I don't have any walls large enough. Too many damn doors and windows! One of those at about 4'x6'x6'' on each adjacent wall would probably kick ass, and well as one on the back wall opposite of the TV and front speakers.

I have built systems around the OC 705. Basically, built a box out of trim with a fabric track system on the inside edges of the trim. Cut the fiber panel to fit the inside of the box, and stretch fabric across. Pretty easy. I need to find pics.

I have never tried to apply fabric directly to the OC panels; I've always bought them pre-done from Kinetics, and recently Auralex.

<edit>This is not my work, just a pic I found showing a fabric track system. You don't have to do the whole wall.
http://www.zeronoise.com/sound_contr...AX-THEATER.jpg

from outside to inside layers:

you need a small texture, porous surface to address high frequency reflections and absorption.

you need a soft layer to absorb energy below that.

you need a dense, thin layer to move with the transmitted sound and vibrate it away into heat. ideally something with no "springiness" like lead or tar paper or something.

you need another soft foam layer behind that to allow the movement of the dense layer

you need a firm structure behind it all.

...

you could probably make it out of

grill cloth on top of soft open cell urethane foam (at least two inch thick) followed by some roofing paper/underlayment or even the mcmaster carr sound deadener sheet followed by another inch of open cell urethane foam and attached to some kind of backer.

I suspect you'll need some nails or something to keep it from all sliding down the side of the wood though.

Yes there you go that is what I am thinking. It should be good for a first try anyway. That fabric track system, is that the same sort of thing that is used for screen doors? That is, there is a little piece of tubing that gets pressed in to a channel with a roller that stretches and holds the fabric? That would make finishing really easy.

I am just not sure where I can get the OC 705 locally. I know that is what is considered to be the way to go but it seems like there should be something at the hardware store that would be good enough.

EDIT: Here is someone talking about using 'duct board' instead of 703
http://www.gearslutz.com/board/so-mu...uct-board.html
For non-structural wall treatments and/or bass traps that would be REALLY easy. Just cut to size, stretch some nice looking fabric over the duct board, staple onto the back, hang on the wall, done.

I've never really studied a screen door, but I'd imagine it's similar. Sounds the same.

Here's something from google
http://www.wallmate.net/images/wall1.gif

I've never tried to stretch fabric over the board itself. It's kind of hard to cut to put a super nice edge on it, so I've always purchased that type of stuff pre made. If you found some board that was already cut to the size and shape you wanted, then Matt's idea of using speaker cloth would be great.
When you build the fabric track system, it doesn't matter that the board is cut sloppily because it's all completely hidden.

Well I hung some curtains in the room on the windows on the side walls (dormers) and about 3' in front of the wall that is behind the TV. There was definitely some room coupling (standing wave?) going on before because the sub is even flatter now. I am still really pleased with the setup.

Definitive Technology Promonitor 1000 speakers sound really sweet, especially for the price. I picked up a pair used, but in new condition, and they sound fantastic.