# Very Affordable Acoustic Treatment



## Mark Techer (Jan 17, 2008)

I first heard about this concept from an unlikely source - a well known and respected HT designer. After discovering how affordable this stuff is, I decided to test some out with quite amazing results. For what this stuff costs, this would have to be the BEST bang for buck room acoustic treatment around.

Check this out: 










A rough bitmap of what my room looks like showing the treatments (in black) which is basically the 1st 1/3rd of the room and half the height of the other 2/3rds. 

And a photo before the screen went in. 










At this end of the room, there is no audible slap echoes and I will even demo this point to visitors to the room.

Apart from its awesome sound absorption properties, this stuff is also a total light sponge, so ideal for around the screen to soak up that reflected light from the screen that tends to bounce off the walls and wash the image out.


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## bpape (Sep 14, 2006)

What is 'this stuff' ? If it's just like a heavy curtain, it's great for upper mid and high frequencies but is doing basically nothing in the bass through lower midrange frequencies.

Not trying to burst your bubble, just trying to see what it is you have.

Bryan


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## Mark Techer (Jan 17, 2008)

bpape said:


> What is 'this stuff' ? If it's just like a heavy curtain, it's great for upper mid and high frequencies but is doing basically nothing in the bass through lower midrange frequencies.
> 
> Not trying to burst your bubble, just trying to see what it is you have.
> 
> Bryan


Exactly, it takes care of the offensive upper-mids and highs. You still need bass traps and denser treatments for total control of bass and mid range. This is simply car carpet that is stapled, not glued to the wall. It won't work as well if glued as apparently it needs the air gap behind to absorb the sound waves that pass through and reflect off the wall. I've not had a chance to measure the exact in room response yet. 

My budget for this room was tight, so for less than $400, I honestly don't think I could have found another product that would work as well.


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## Zeitgeist (Apr 4, 2009)

I'm sure that carpet has absorption properties that are very different from 1" fiberglass, but it seems like carpet might still be quite effective? I mean, unless you're using bass traps or very thick fiberglass, my thinking is that 1" wouldn't do a whole lot more than carpet would.

I know that fiberglass has measurable quantifiable performance - and it's intended for absorption.. but for the large square footage and low cost....... the carpet looks quite interesting.


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## Prof. (Oct 20, 2006)

That's interesting Mark..
Do you have your entire front wall covered, behind the screen wall?
The stuff looks exceptionally black for car carpet..Is it a close pile or those fluffy type carpets?

PS..That's a very cool look with the ceiling and wall colour done like that!:T


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## Mark Techer (Jan 17, 2008)

Zeitgeist said:


> I'm sure that carpet has absorption properties that are very different from 1" fiberglass, but it seems like carpet might still be quite effective? I mean, unless you're using bass traps or very thick fiberglass, my thinking is that 1" wouldn't do a whole lot more than carpet would.
> 
> I know that fiberglass has measurable quantifiable performance - and it's intended for absorption.. but for the large square footage and low cost....... the carpet looks quite interesting.


In the end of the day, it was a case of seeing what worked and what didn't. The carpet surprised me with how good it worked for both sound and light. It seems like some people think that treatments need to work all the way down to 20Hz. This is simply not the case as you still need speaker/room interaction. Room treatments are about finding the perfect balance and you can over treat a room. 



Prof. said:


> That's interesting Mark..
> Do you have your entire front wall covered, behind the screen wall?
> The stuff looks exceptionally black for car carpet..Is it a close pile or those fluffy type carpets?
> 
> PS..That's a very cool look with the ceiling and wall colour done like that!:T


Yes the entire front wall and a portion if each side wall is treated from floor to ceiling. The rest of the bottom half of the room is also treated. This is simply Bunnings car carpet and you can buy this off the roll in 1m and 2m widths. It comes is a few colours including a rich blue, though I just bought black. It is reasonably tight loop and it was fairly cost effective. It has worked out well for me why I thought I would share. 

The grey paint is the same "Pompeii Ash" I used in my house in 2006. I like the stormy cloud look I've been able to get. I would have liked it to be darker, however that is the darkest they make and adding black to it will change the texture and the end result.


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## bpape (Sep 14, 2006)

For informational purposes:

1" 703
---------
0.11 0.28 0.68 0.90 0.93 0.96

Heavy 5/16" carpet (approx)
---------
0.05 0.15 0.30 0.40 0.50 0.60

1000 cubic feet of air
---------
0.00 0.00 0.00 0.09 0.23 0.72


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## Zeitgeist (Apr 4, 2009)

Thanks Bryan - That's actually what I started looking for yesterday - out of curiosity.


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## Prof. (Oct 20, 2006)

Mark Techer said:


> Yes the entire front wall and a portion if each side wall is treated from floor to ceiling. The rest of the bottom half of the room is also treated. This is simply Bunnings car carpet and you can buy this off the roll in 1m and 2m widths. It comes is a few colours including a rich blue, though I just bought black. It is reasonably tight loop and it was fairly cost effective. It has worked out well for me why I thought I would share.


Bunnings eh!..That's good to know..:T 
Are you using this same carpet on your baffle wall as well? 



> The grey paint is the same "Pompeii Ash" I used in my house in 2006. I like the stormy cloud look I've been able to get. I would have liked it to be darker, however that is the darkest they make and adding black to it will change the texture and the end result.


You did that cloud effect!!? Very nice..:T


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## Prof. (Oct 20, 2006)

I've just noticed back in your other thread that you say you used 1" convoluted foam on the baffle..
Where do you get black convoluted foam? I've only ever seen it in a yellow colour like those mattress overlays!


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## Mark Techer (Jan 17, 2008)

Prof. said:


> Bunnings eh!..That's good to know..:T
> Are you using this same carpet on your baffle wall as well?
> 
> No the Baffle Wall itself uses a 1" foam.
> ...


Yeah I liked it in the first room, so thought I'd stick with what worked 



Prof. said:


> I've just noticed back in your other thread that you say you used 1" convoluted foam on the baffle..
> Where do you get black convoluted foam? I've only ever seen it in a yellow colour like those mattress overlays!


It is actually dark grey. If you go Clarks Rubber, they have the stuff, but charge you more for one half sheet (convoluted foam comes as a nested pair) than I paid for the 3 full (nested pairs) sheets. From memory, the grade is 28/400 and it only comes in grey. Other colours will be different densities or simply softer foams like the ones used on mattresses which tend to be lighter colours like greens or yellows. I need to find a new supplier for this stuff, however Dunlop foams will sometimes supply general consumers with product. I have an ABN so qualify for an account with them however they would not do so last time I asked. Not sure why.


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## Prof. (Oct 20, 2006)

Thanks for that Mark..
I think my nearest Clark Rubber store is about 60K from here but it's only a small branch..I might have to make the 100K trip to Adelaide to get the right stuff! Still sounds like it's worth the trip!


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## Mark Techer (Jan 17, 2008)

Here is a close up of the foam.


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## Prof. (Oct 20, 2006)

I've just found out that the Clark Rubber store that's nearest to me does have the 28/400 foam..
They have it in 2030x1520 sheets at $152.00/sheet..Not bad really!


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## Mark Techer (Jan 17, 2008)

Yeah not too bad. They will most likely sell you one half, not the full nested pair though.

Convoluted foam is the only product in the foam cutting industry that goes into the machine at one thickness and comes out at almost twice as thick. This happens because of the shape of the special rollers that pushes on the foam as the blade cuts it. As the roller releases the foam, what was pushed up is now a recess. This happens on both sides as the blade slices through the middle. The end result is two pieces of foam with varying thicknesses that can be nested together.


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## Prof. (Oct 20, 2006)

So are you saying that this convoluted foam is actually made double sided and they split it in half to have one side flat!?


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## Mark Techer (Jan 17, 2008)

No the convoluted foam is split in the centre, but special rollers compress the foam as the blade slices it. The result is two halves with bumpy surfaces on one side.


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## Prof. (Oct 20, 2006)

Sounds like the nested pair is the way to go, if Clark's will sell it like that..


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## Mark Techer (Jan 17, 2008)

Go armed with the right information and they might. Generally, no. They sell it by the single sheet (half) and you pay for area.


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