Sonic Barrier vs Egg Grate Foam

[m1ke323]

I am looking for a nice dampening solution for my speaker I am building. The sonic barrier 1" and 1/2" is alot more expensive then simple 1-1/2 egg grate foam from PE. This will be going in a floorstanding speaker with about 2-3 cu ft enclosure.

Which choice would be best, or is there another solution that would work better. I searched alot to find an answer but could find to much. Thanks

Mike

[Amphiprion]

Are you wanting to damp panel resonances or damp standing waves in the enclosure?

[m1ke323]

This is going inside Dennis's TMWW RS 3-way design. Black Hole 5 and others dampen panel resonances and standing waves.

I know I should dampen the standing waves with some sort of foam, but I am not sure if I need to dampen panel resonances with some PE Sound deadening stuff, like http://www.partsexpress.com/pe/showd...number=268-020.

Also, is the Sonic Barrier 3-Layer stuff from PE worth it over the 1/2" and 1" regular sonic barrier?

Regular: http://www.partsexpress.com/pe/showd...number=260-525
3-Layer: http://www.partsexpress.com/pe/showd...number=260-530

Mike

[ThomasW]

Take a hint from all the other builders, no one has used anything like BH5.

If the cabinet is properly constructed, the only thing needed is standard acoustic foam, poly fill or fiberglass.

[m1ke323]

Thats what I like to hear Thomas. Can I ask what you normally use to line your cabinet?

My cabinet should be built like a rock, my woodworking skills are pretty good. So I will just use some 1" wedge from from FoamByMail.com, sound good or is there something better?

I plan on lining the entire sealed woofer cabinet with foam, but for the midrange and tweeter cabinet, should I just stuff that with polyfill since the cabinet is so small?

I really appreciate the help guys. Thanks. Also, I start gluing my cabinet together today. It has curved sides so it should look pretty slick.

Mike

[ThomasW]

I use high wool content felt gasket material to line the walls. Then I fine tune with long fiber wool if we're dealing with midrange frequencies.

Both these are very $pendy. I use them because a long time ago I bought a ton of both and have it in storage.

For the woofer section fiberglass batting is better than acoustic foam. If you want to use foam I'd use 1.5"

Polyfill is fine for the mid chamber

[m1ke323]

Thanks for the quick reply.

[m1ke323]

I looked for the Fiberglass batting and couldn't find anything besides regular home insulation. So I was going to go with foam, but didn't know if there was a difference between egg grate and wedge foam for the woofer cabinet?

[ThomasW]

I looked for the Fiberglass batting and couldn't find anything besides regular home insulation

Yes that's what you want to use regular home insulation.

[KJP]

I use them because a long time ago I bought a ton of both and have it in storage.

Watch out for moths. Moths LOVE wool in storage. :rofl:

[cobbpa]

On the foambymail.com site posted earlier, the egg crate foam is sold listed with difference frequencies; I assume frequencies it deadens best? What would be best used in a woofer enclosure? And if covering all the inside walls with thick foam, does it ever alter interior volume in amounts to be concerned over?

[Jim Holtz]

On the foambymail.com site posted earlier, the egg crate foam is sold listed with difference frequencies; I assume frequencies it deadens best? What would be best used in a woofer enclosure? And if covering all the inside walls with thick foam, does it ever alter interior volume in amounts to be concerned over?

Here is what I use and can recommend. http://www.foambymail.com/Wedge.html in the 2" variety. It has a NRC rating of .81 which should be effective. As you can see from the chart, it's most effective in the mid and upper frequencies.

Brace the cabinet well and line it with the 2" foam and you'll have no worries.

Jim

[noah katz]

"does it ever alter interior volume in amounts to be concerned over?"

Yes, it actually effectively *increases* box volume by absorbing the heat of compression and lessening the air pressure rise each cycle.

[JonW]

Have any of you folks used Whispermat?

http://www.silentsource.com/barriers-whispermat1and2.html

I've seen it mentioned now and then. I'm building the Modula MT's (ported). And trying to decide what to use inside. I've got some poly batting around the house. (From building a sub, not making pillows. :P ) My cabinet is very well braced, but it never hurts to have extra dampening added to the cabinet, I'd think. So maybe the Whispermat would provide both dampening as well as the absorptive properties? And then skip the poly batting? Idunno really...

[Mazeroth]

http://zaphaudio.com/whispermat.html

[Dennis H]

JonMarsh uses Whispermat. Do a Search - Advanced Search - Username JonMarsh, Keyword Whispermat - display as Posts.

[ThomasW]

Jon bought a bunch of Whispermat long ago. It's now considerably more expensive than what he paid.

For speakers like the Modula or NatP, etc, I don't think products like Whispermat will provide much of a benefit. If one wants to experiment, I really think that a DIY version made with the PE bituminous pad and acoustic foam is more than adequate.

Looking at the Frequency/Transmission loss/dB, Whispermat it doesn't really kick in until the upper midrange and treble. At those frequencies boxwall damping isn't an issue and those higher frequencies are easily absorbed by any of the standard fibrous materials we use.

[m1ke323]

I just read a post about a person saying that there Nat P was over dampened, and that once he took out one of the pieces (I think it was the piece on the back) it sounded much better.

Are you suppose to line the sides, rear, top and bottom with foam, or just the sides and back, or what? Thanks

Mike

[JonW]

The Whispermat looks quite interesting- it has vibration dampening and looks to have foam sounds absorption properties. So from a purely intellectual standpoint, it’s appealing. Jon’s and Zaph’s using it also sounds good. It’s pretty pricey these days, with the smallest sheet available (54”x72”) around $100, but that should last for many speaker projects.

Here is what I use and can recommend. http://www.foambymail.com/Wedge.html in the 2" variety.

I’ve heard enough people malign foambymail that I’m a tad hesitant to use their stuff.

For speakers like the Modula or NatP, etc, I don't think products like Whispermat will provide much of a benefit.

Is there a situation where you would recommend it?

If the cabinet is properly constructed, the only thing needed is standard acoustic foam, poly fill or fiberglass.

I have some pretty extreme bracing worked into my cabinets. Over-engineered, you know. So maybe I’m OK to just use the extra poly batting I have from building the sub. I also have some OC 703 for making room treatment panels. And some extra R19 fiberglass from some house repairs. But buying something different would be fine as well. Hmmm…

[ThomasW]

Are you suppose to line the sides, rear, top and bottom with foam, or just the sides and back, or what? Thanks

Mike

This is one of those subjective areas. One can in essence 'fine-tune' the cab to taste.

The guy with the problems wallpapered the inside of the box with 2.5" thick foam. IMO that's something that should be used for subs, not little bookshelf speakers.

[ThomasW]

The Whispermat looks quite interesting- it has vibration dampening and looks to have foam sounds absorption properties. So from a purely intellectual standpoint, it’s appealing. Jon’s and Zaph’s using it also sounds good. It’s pretty pricey these days, with the smallest sheet available (54”x72”) around $100, but that should last for many speaker projects.

Is there a situation where you would recommend it?

Not really. At the current pricing for Whispermat, I'll continue to use the high wool content felt gasket material I've used for decades. This has been my standard damping for fullrange speakers and I've also used it in subs, but doing that gets $pendy very fast.

I picked up a couple packs of a new product from MCM. It's an interesting mix of poly and wool. Should be perfect for small speakers like the NatP or Modula designs. MCM damping pads

[JonW]

Not really. At the current pricing for Whispermat, I'll continue to use the high wool content felt gasket material I've used for decades. This has been my standard damping for fullrange speakers and I've also used it in subs, but doing that gets $pendy very fast.

I picked up a couple packs of a new product from MCM. It's an interesting mix of poly and wool. Should be perfect for small speakers like the NatP or Modula designs. MCM damping pads

Interesting- thanks.

I guess this is probably a place for me to to experiment a bit. I can try varying amounts of poly batting or R19 or OC703 and see how things sound. Maybe even pick up some of that MCM stuff.

[noah katz]

"I’ve heard enough people malign foambymail that I’m a tad hesitant to use their stuff."

This is the first I've heard; what were the problems, or do you have a link?

Thanks

[Brandon B]

I have two unused rolls of whispermat in my garage (also from my defunct DIY MTM speaker plans). It has the embossed layer on it.

When I get home I will figure out how much I have (it's quite a bit). Anyone interested PM me.

BB

[Brandon B]

Well I have two rolls of this stuff, about 56"x72" each. It is 1=1/2" thick, with 1/2" of foam - then the absorption layer - then 1" of foam - then the surface layer, looks like the aluminized polyester with reinforcement. Not the embossed type after all. I got it from these guys:

http://soundown.com/AI.htm

Bought this stuff a few years ago. At this point, I am not going to use it. I'll post it in the Pawn Shop forum.

BB

Edit: posted:

http://www.htguide.com/forum/showthread.php4?t=21168

[Martyn]

At the risk of sounding pedantic: if you wish to damp your speakers, the various materials mentioned above will do the trick. If you wish to dampen your speakers, water is best!

[JonW]

"I’ve heard enough people malign foambymail that I’m a tad hesitant to use their stuff."

This is the first I've heard; what were the problems, or do you have a link?

Thanks

Hi Noah,

Sorry, I don't have any links. And I don't mean to say anything bad about the company- I have zero experience with them. The only audio web boards I read are the DIY forum here and some of the various ones over at avsforum.com. So it had to be one of those places. Do a search, I guess. But I've seen it come up multiple times. Maybe it was on avs when I was looking into various options for making room treatment panels. I seem to recall people saying that foambymail's claims or "measurements" of sound absorption were pretty far off the truth. Idunno... Sorry I can't be more specific.

[JonW]

At the risk of sounding pedantic: if you wish to damp your speakers, the various materials mentioned above will do the trick. If you wish to dampen your speakers, water is best!

:rofl:

Actually, I find a nice 1" thick layer of water damps my speaker cabinets quite effecitvely.
:P

[Martyn]

:rofl:

Actually, I find a nice 1" thick layer of water damps my speaker cabinets quite effecitvely.
:P

Now, if you could apply it as a self-adhesive, self-supporting gel...

[JonW]

Now, if you could apply it as a self-adhesive, self-supporting gel...

Although it's purely a coincidence and nothing to do with audio... I just happen to be designing hydrogels with adhesive properties, among other things, here in my lab. (seriously) Hmmm... maybe we could adapt it for speaker building. We'd have to get around that annoying evaporation thing. Maybe just sell it like a plant- you've got to water or mist it every now and then. Living speakers for live sound.

[m1ke323]

I realize I am beating this subject to death, but I am buying the foam tonight and am trying to decide between the MCM stuff Thomas posted and the 1" or 2" wedge foam from foam by mail. The MCM stuff seems like it would fall apart so I kinda prefer the wedge foam.

Would you guys use the (1" w/ nrc .52) or (2" w/ nrc .81) wedge foam for a 2.5 cu ft enclosure with dual RS225's in it. This is for the TMWW design if you haven't read the entire thread.

[Amphiprion]

2" definitely. I ordered a variety of 2-3-4" wedge and pyramid samples from them.

[ThomasW]

The MCM stuff seems like it would fall apart so I kinda prefer the wedge foam.

The MCM stuff is a 'pad' that can glued, stapled or whatever in place. It looks perfect for midrange, midwoofer use in a small box. Given smallish size of the pads, they'd be pain for a big woofer/subwoofer box.

[Jack Gilvey]

How 'bout OC 703 to line a cab? Any use?

[ThomasW]

How 'bout OC 703 to line a cab? Any use?

Pete Mazz has used it successfully several times. There are some pics on his website and in his threads

[Jack Gilvey]

Ok, thanks. It's a much more effective absorber down lower than foam, and I was wondering if that mattered in this application.

[ThomasW]

I think dacron/wool/acousta-stuff/whatever are better choice for pure midrange.

Often Jon and I line the box with wool felt, then put a plug of dacron or longfiber wool directly behind the driver if the sytem is a 2-way

[jquin]

Jon bought a bunch of Whispermat long ago. It's now considerably more expensive than what he paid.

For speakers like the Modula or NatP, etc, I don't think products like Whispermat will provide much of a benefit. If one wants to experiment, I really think that a DIY version made with the PE bituminous pad and acoustic foam is more than adequate.

Looking at the Frequency/Transmission loss/dB, Whispermat it doesn't really kick in until the upper midrange and treble. At those frequencies boxwall damping isn't an issue and those higher frequencies are easily absorbed by any of the standard fibrous materials we use.

At the risk of angering the great God ThomasW ;x( do you think WhisperMat is still advisable for my M8ta build.
I am coming to the States again soon and can bring some back with me but it is a major pain in the "you know what" :M to do so.

I'm being very prescriptive with the M8ta build till now but if I can get out of using WhisperMat then Whooo hooo!!!

[jquin]

Never Mind Thomas

I have made up my own mind that I'll ditch the Whispermat.

Damn its hard to assimilate all this info

I'm guessing its no where near as hard as Moderating a forum full of newbies. ;x(