An "Off The Wall" Question

[RedWallStudio]

I am planning on building some 703 and 705 based absorbers for my live room and for my control room. My floor to ceiling height is 9 feet, and the panels I am building will be approximately 2 feet wide and 8 feet tall and 4 inches deep (with 2" thick 703 or 705 at the front of the frame). My question is, how much benefit do I gain by hanging them away from the wall by a few inches? I am going to hang them from the ceiling, so I can set them away from the wall 2, 4 or up to 6 inches. What do I gain by hanging them away from the wall 6" over 2"? Is it worth wasting that space? Thanks!

[Eric_Desart]

That depends if your aiming at specific frequenties or not.

For broadband until lows the 6" distance is best.
For thin panels the 705 will work more as a membrane damper than the 703, which maybe will be positive.

But in the same total distance you could also use 4" 703, which I should prefer versus 2" 705 for about the same cost (not incl. frame of course).

But there are different visions about this.

Eric

[Ethan Winer]

> with 2" thick 703 or 705 <

I agree with Eric that two inches is not thick enough. Four inches will give much better results because that absorbs well to a lower frequency. So using four inches of rigid fiberglass spaced four inches off the wall does a really good job.

--Ethan

[Mario Petrinovich]

> with 2" thick 703 or 705 <
I agree with Eric that two inches is not thick enough. Four inches will give much better results because that absorbs well to a lower frequency. So using four inches of rigid fiberglass spaced four inches off the wall does a really good job.
--Ethan

If somebody is looking for a radical solution, what you people think about 6 inches thick? Spaced 2 inches if you need more free space in room (on a side walls), or 6 inches where you don't need so much free space (front and back walls). Is it only more costly, or would it cause some problems? Is this too thick? I guess its better to have, let's say, 15 sq. feet of 4 inches thick, than 10 sq. feet of 6 inches. Or is it so? I mean, if 6 inches are at strategic places, like first reflection points. -- Mario

[Ethan Winer]

Mario,

> what you people think about 6 inches thick? <

Not radical at all, and being thicker never causes problems. When the material thickness or air gap are increased, the absorption extends to a lower frequency. And this is always a good thing.

--Ethan

[Mario Petrinovich]

Mario,
> what you people think about 6 inches thick? <
Not radical at all, and being thicker never causes problems. When the material thickness or air gap are increased, the absorption extends to a lower frequency. And this is always a good thing.
--Ethan

Thanks. -- Mario

[RedWallStudio]

Thanks for all the info! I had to go with 2" material because it was all that was available.. but I am assuming I can just add two 2" layers together to make 1 thicker layer. My follow up question would be this: If I am going with two 2" layers... would I be gaining any benefit by putting an air space between the two 2" layers AND then a 4" space between the finished "air sandwich" and the wall. So it would go 2" Rigid Fiberglass/2" Air/2" Rigid Fiberglass/4" Air. Make sense?

[Ethan Winer]

Red,

> I am assuming I can just add two 2" layers together to make 1 thicker layer. <

Of course.

> would I be gaining any benefit by putting an air space between the two 2" layers <

I've never tested that, but my gut feeling is this is not a good idea.

--Ethan

[Eric_Desart]

Thanks for all the info! I had to go with 2" material because it was all that was available.. but I am assuming I can just add two 2" layers together to make 1 thicker layer. My follow up question would be this: If I am going with two 2" layers... would I be gaining any benefit by putting an air space between the two 2" layers AND then a 4" space between the finished "air sandwich" and the wall. So it would go 2" Rigid Fiberglass/2" Air/2" Rigid Fiberglass/4" Air. Make sense?

Red,

You can combine as many layers together as wanted hence 4" resulting from 2+2 is OK.
In some cases if it's easier to mount or you like larger panels, you can glue them with an offset (staggered versus one another) with spray contact glue (only using minor bit), but you don't need to.

Use maximum space you can spare and just keep the boards together, rest is gap. (my belly speaking, not measured).

Eric

[RedWallStudio]

Thanks Eric.... Thanks Ethan!

I would also like to use my 703 and 705 panels to help isolate a drum kit in one corner of my live room. I have 4 feet x 8 feet sheets of both 703 and 705. Assuming I can come up with a way to attach them to each other and to the ceiling and floor, which will create a small "drum room". How thick would you think these would need to be to isolate the drums? I know I will have some air gaps between panels etc.. so Im not expecting to make something sound proof... just a decent improvement over having the drums out in an open room.

[Eric_Desart]

Red,

I can't see that picture. Does the forum accept TIF or is it my CPU?

Anyhow, I'm not sure to understand your question.
Do you want to use absorption material as insulation material?

That will work a bit in the highs and only poor in the lows. Hence you drums will still sound loud but with a raped spectrum, all brilliance gone and still loud.

[RedWallStudio]

I think it may be my formatting that is preventing the pic from going up.

Anyhow, hopefully I can explain better. I am looking to create a drum iso booth which will be inside a much larger room. But I want to be able to make it temporary. So I was going to build panels that go from ceiling to floor that I can surround a drum kit with. For the sake of example, I would build 8 panels that are 4 feet wide and 8 feet tall. Connecting all 8 panels would make a square that would go from ceiling to floor..and surround a drum kit. Im just looking to see how thick I would need to make it to really isolate the drums. Or would I be better off using a material different than 703 or 705? Hope this makes more sense.

[Eric_Desart]

You should be more clear about the notion "to really isolate the drums"

If I take this literally you have to build a traditional double framed gypsum board wall.
Anf if open without a good door, you still will be far from "to really isolate the drums".
And if a door is build in you really need to do something about absorption inside because I (wild) guess your kick drums will show peak levels around 70 to 80 Hz.

Eric

[RedWallStudio]

Sorry for not being clear about "really isolate". I guess I got that term and my idea from this:

http://www.realtraps.com/products.htm#gobotraps
(the term "isolate" is used right below the drum kit picture.... does isolate mean anything different than "really isolate"?)


Im just looking to build traps that go from floor to ceiling and will surround the drum kit.. but are movable, so I can use them for other uses. Im just trying to avoid permanent drywall walls. I guess it will be up to trial and error.

[Eric_Desart]

Sorry for not being clear about "really isolate". I guess I got that term and my idea from this:

http://www.realtraps.com/products.htm#gobotraps
(the term "isolate" is used right below the drum kit picture.... does isolate mean anything different than "really isolate"?)

Im just looking to build traps that go from floor to ceiling and will surround the drum kit.. but are movable, so I can use them for other uses. Im just trying to avoid permanent drywall walls. I guess it will be up to trial and error.

What I mean with "really isolate" is:
If you really want an isolated booth for your drums, meaning you want an isolation of 20 dB or higher you have little choise than going the traditional isolation route.

If you just want a separation, where at a short distance you need some isolation, than such stands are OK (they absorb a bit and work as a screen).

Such Gobos are not really meant to created an isolated booth.

Therefore what do you mean with "really isolate". at longer distance -5 dB, -20 dB, -30 dB, more?

With gobos acting as a screen the isolation is defined by the position of source and receiver versus screen + what gets through, hence is very dependent of how it is used. But it never will give much of real isolation.

Even when you make them large, there will be leackage

In order to tell anything sensible, you must define what exactly you expect from something.
"Really isolate" is like playing chess, varying between knowing where the pieces are allowed to go and being grand master. It is all real chess play.