[jk@home]

This is a little off the wall, but...I'm finishing up with my room treatments for this setup:

http://www.audiocircle.com/index.php?topic=128954.20

Current building some custom 4" and 6" absorption panels to go on the vaulted wall to ceiling transitions on the front and back wall. Then I will be done building panels for a while.

But I also want something on the tops of my mid-bass subs. Acoustically, they are placed where I want them, but are also right in line with the first reflect points off the front wall, and direct energy off of the KEF speakers . Plus that vaulted section on the front wall (which will be partially treated with three 20 x 24 x 4 panels) aims right at them. They're finished in a Duratex coating, so no high end finish to damage.

I could take the easy route and throw a couple of matching cotton blankets on top, folded up. I know foam really isn't that effective (Auralex, etc.). But how about this foam? Have bought this before and is pretty durable. :

http://www.parts-express.com/sonic-barrier-1-1-4-3-layer-acoustic-sound-damping-material-with-psa-18-x-24--260-535

Any other ideas (other than a trip to the nut house  )?

[BobM]

That foam appears similar (knockoff?) to Black Hole 5. Black Hole 5 is commonly used inside a speaker as damping material, working better then plain foam and such. They claim it actually appears to the speaker as if there is a larger enclosure than is physically there.

Now, as an acoustic "baffle" on top of the subs? I don't know. I would suggest putting a nice plant on top of each - looks attractive and acts as a kind of diffuser.

[BPT]

JK:
Yes, it will make a difference. I think you are better off using regular acoustic like this: http://www.parts-express.com/acoustic-sound-damping-foam-sawtooth-wedge-wall-tile-california-prop-65-compliant-ul-94-2---260-512

[jk@home]

Thanks guys. I thought about Auralex's 4" pyramid stuff, it is kind of a diffuser and abosorber in one, but it is wayyy over priced. The foam from Pe looks much more reasoanable.

What would be the best way to orientate the pieces, grooves front to back, or side by side (which to me would make sense)?

Then again the tops of the subs are 18" x 18", so I would have to piece several 12" foam squares on each. Maybe do an alternating pattern of some sort.

[Hipper]

I've used Auralex foam. I can't believe the 2" thick parts express pieces linked to will go anywhere near as low as they claim. Tests show Auralex's 2" foam goes to 500Hz then tails off as you go lower. I believe the key factor with foam is the air pocket size. Perhaps better foam has more consistent size, hence is more expensive? Auralex used to make a 12" cube block of foam for corners which may suit your needs.

I now use GIK products. You could use some small panel type pieces, perhaps with artwork on them.

What you really need are the target frequencies you are looking to deal with and the specs of the products you are considering.

[jk@home]

Just to follow up, I went back and forth between the foam, and the (guaranteed crappy looking) cutting job that would of been needed to cover the entire tops of the subs, or building a couple of custom sized OC703 panels, which I already have the materials to do.

Said the heck with it and ordered a couple of black acoustic blankets. One of the apps of these are to drape over objects to reduce reflections in a studio. I figure I can fold them up, and cover the tops and backs of the subs, catching reflections off the speakers and the QRDs. Something a little different, basically fancy dancy moving blankets.

https://www.vocalboothtogo.com/acoustic-and-soundproofing-products-vocal-booths/acoustic-(sound)-blankets-for-sound-absorption---producers-choice/acoustic-blanket-producers-choice-solid-black/8-24#ja-pathway

[jk@home]

Got the blankets and strapped them tight to the subs with 2" Velcro One Wrap strapping. Hardly had to unfold them, they were folded to 18" wide out of the box. A decent quality product (about $25 each) and there is an audible improvement using them in this way, so they are staying.

[BobM]

It looks nice and cozy.

[jk@home]

LOL, they may come in handy next winter They are actually quite heavy.

[mresseguie]

Pretty neat, jk!

Somehow, I completely missed this thread till now. I've considered buying just this sort of sound absorbing blanket a couple times, but either laziness or fear of WAF has prevented my acting on impulse.

Is the mid-bass speaker self-powered? I ask because my first thought was, "Won't the amp at the back over-heat?" Of course, if it's a passive unit, no worries!

Over a year ago, I purchased a pair of Auralex foam speaker pads for about $50. Then, four months ago I walked into a store in town that sells all things foam. The same exact foam that Auralex glues their logo onto can be purchased for $5!  Granted, the Auralex pads are cut at a cute angle and the cheap stuff is flat, but the foam guy can cut at angles too. Talk about gouging the customer.....

I may yet buy a couple of those blankets.

Enjoy!

Michael

[jk@home]

Yes the subs are passive, I drive them with a outboard Yamaha P3500S pro amp. Speaking of Auralex,  I went overboard with the bracing when I built these, and they weigh around 80# each. I originally was using a pair of the Auralex Sub Dudes as platforms. They worked as advertised, but evidently the weight of the speakers were too much for the Dudes and after a while the foam must of started to break down causing the subs to list over slightly. So now I use a sandwich combo of cutting board > sorbothane pads > concrete paver > more  sorbothane pads > sub.

There is a video on the web that shows how to cut Auralex foam wall treatment, using an electric carving knife. I knew if I wanted to cover the entire 18" square tops of the subs, I would of had to buy a 2 x 2 foam piece and carve up it to fit. And knew I would of butchered it. This was much easier.

One last thing. There is a thread on the Gearslutz site regarding these, and a big stink about the "stink" of them. One of the principals of the company replied on the thread, went as far as acknowledging the problem and how they solved the issue. I even inquired about this when I bought mine. There is a slight odor if one buries their face into the blanket, but really a non-issue.

[Rob Babcock]

Nice!  For the price it looks like a fix well worth trying.