stacking insulation rolls as corner bass trap?

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eyeballing

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Hi all. I think this topic would had been discussed few times, but I found too many conflicting answers, so I wanted to bring this topic once more.

I heard some people bought those rolled insulation and stack them as is, without unwrapping it or doing anything do it, and that makes something similar to superchunk bass trap but thicker, hence awesome bass absorption.

What I have in mind is Johns Manville R-30 attic or Owens Corning R-30. JM works better for me because I can actually find them in the store and they offer 24" thickness, which I can simply stack 4 to fit my 8' ceiling.

Any opinions or experiences on this method?
 
It should definitely help, I have seen cylinder style bass traps that work so same principle. The style of bass trap does change how low it goes, but anything is an improvement

Alan
 
Yes, I am sure it works. I read about someone that stuffed several rolls of GF still in their plastic bags under a staircase in a room as a temporary measure until they had the time to make some proper traps. I think there was also the problem that they might have to move and so could sell or use the GF if that happened. In UK at least, if you have laid insulation it becomes "fixtures and fittings" and you cannot remove without consultation, pretty sure.

Dave.
 
It's not a trap though is it? Just an absorber that works lower because of the size and depth. Traps absorb, and have a cut-off above which they don't work, leaving some other treatment to sort those. It will work even better on HF. The wrapper might work as a membrane if it was thick, but thin poly won't do much.

I suspect that so many 'traps' that we stick in corners are just wide band absorber, and we have become used to calling this a trap.
 
rob aylestone said:
It's not a trap though is it? Just an absorber that works lower because of the size and depth. Traps absorb, and have a cut-off above which they don't work, leaving some other treatment to sort those. It will work even better on HF. The wrapper might work as a membrane if it was thick, but thin poly won't do much.

I suspect that so many 'traps' that we stick in corners are just wide band absorber, and we have become used to calling this a trap.
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We_____el! In the case I cited the GF was behind the listener so he/she would get the full mid/hf coming from nearfield monitors whereas the omnidirectional bass would get absorbed....Seems to me?

Dave.
 
I had rolls of pink fluffy stuffed behind OC703 panels in all four corners. The panels straddled the corner making a triangle shaped void which I put the roll of pink fluffy. I did that based on ideas brought up here at HR. I don't know if it actually helped my low end or not. My studio is really small, so there's not much help for it anyway.

I had the insulation laying around after I finished another project, but I probably wouldn't go out and buy it specifically for the purpose of acoustic treatment.
 
ecc83 said:
Yes, I am sure it works. I read about someone that stuffed several rolls of GF still in their plastic bags under a staircase in a room as a temporary measure until they had the time to make some proper traps. I think there was also the problem that they might have to move and so could sell or use the GF if that happened. In UK at least, if you have laid insulation it becomes "fixtures and fittings" and you cannot remove without consultation, pretty sure.

Dave.
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Thanks for the info! Do you by any chance know specific type or model name of the insulation they used?
 
Chili said:
I had rolls of pink fluffy stuffed behind OC703 panels in all four corners. The panels straddled the corner making a triangle shaped void which I put the roll of pink fluffy. I did that based on ideas brought up here at HR. I don't know if it actually helped my low end or not. My studio is really small, so there's not much help for it anyway.

I had the insulation laying around after I finished another project, but I probably wouldn't go out and buy it specifically for the purpose of acoustic treatment.
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I have a small room too, so this does make me concern whether I should do it or not... I have a 12' x 10' x 8' room, how do you think it would work?
 
witzendoz said:
It should definitely help, I have seen cylinder style bass traps that work so same principle. The style of bass trap does change how low it goes, but anything is an improvement

Alan
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Is it the pipe insulation DIY one? I know just bags of insulation would be as nice as the well made cylinder bass trap, but do you think it would still help in small room? Mine is 12' x 10' x 8'
 
eyeballing said:
I heard some people bought those rolled insulation and stack them as is, without unwrapping it or doing anything do it, and that makes something similar to superchunk bass trap but thicker, hence awesome bass absorption.
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Will it do something? Yes. Will it be most effective? No.

Absorption works by converting acoustic energy to heat. The ability of the sound wave to travel through the materials is relative to its density. The issue with this idea is that rolled insulation is compressed. With higher density, the transition point where the insulation stops being absorptive and becomes reflective becomes shallower. The insulation rating used to model how absorptive is GFR (Gas Flow Resistivity). As depth of treatment increases, lower density out performs higher density materials. OC EcoTouch R30 has a GFR of about 3500-3900 when uncompressed. In contrast semi rigid Safe N Sound mineral wool is 10000 and OC 703 is 20000. Enter these numbers at various depths and you can compare absorption and verify what I am saying. There are a few online calculators. One such is acousticmodeling.com.

If you use an approximately 2ft round roll of compressed insulation, you'll get less absorption than if you uncompressed them and loaded them into basic frames.
 
eyeballing said:
how do you think it would work?
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Your room is a little bigger than mine. When adding absorption to a room, you don't really notice a difference until you listen to your mixes on systems other than your studio. I think I never really had my low end under control and I was always playing a guessing game.

How will it work for you? I don't know. If you have the insulation already, go ahead and use it. If you plan to buy it, maybe save your money... unless money isn't an issue.

You can use a measuring microphone to get empirical data. I have one for sale on eBay. (Search for Dayton EMM-6).

I took measurements in my room and had a big node at 500hz. Nothing I did would attenuate it. So now, I took most of my acoustic treatment down.

Good luck and enjoy the project. The technical aspect can be very intriguing.
 
With smaller square rooms with parallel surfaces, you can't do anything until you sit in it and clap your hands and let your ears suggest how the room sounds, then maybe play some pink noise and move the measurement mic to where you'll be making decisions and see on the screen where the room is lively and/or dead. Then you can pick some appropriate products. If I had problems from maybe 500Hz and above, I'd go to the local DIY store and buy some loft insulation in the poly bags and maybe some more expensive rockwool - also in the bags. Then stick them in the room and repeat the tests. I suspect you'll find the rockwool dampens the results lower in frequency than the loft insulation fibreglass. If you find problems lower down, then the DIY frame with insulation inside and a membrane on the front - my last one was made with shed roofing felt which really worked lower down. Experiment with placing these in the corners first, but in two studios I've been involved with in the last year - reflections from the longer walls straight across were more trouble and wall mounted frames with 100mm of rockwool did a pretty decent job. In my current studio, I have an 8ft x 2ft frame directly above the desk, with just 50mm of foam in and this stops a rather nasty reflection just about 5K.

If you keep the rolls intact, take back what doesn't work for a refund.
 
Folkcafe said:
The insulation rating used to model how absorptive is GFR (Gas Flow Resistivity). As depth of treatment increases, lower density out performs higher density materials. OC EcoTouch R30 has a GFR of about 3500-3900 when uncompressed. In contrast semi rigid Safe N Sound mineral wool is 10000 and OC 703 is 20000. Enter these numbers at various depths and you can compare absorption and verify what I am saying.
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Thanks for the reply. After reading all the comments and little more on the web, I think I will try to build a DIY soffit bass trap instead of stacking wrapped insulation. Figured making a soffit would be a lot cheaper and more useful.

Do you by any chance know if their R value is anyhow related to the GFR? Or the R30 is the most fluffy one?
 
rob aylestone said:
If you keep the rolls intact, take back what doesn't work for a refund.
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Thanks for letting me know. I did change my mind after reading other replies and more online. I figured DIY soffit bass trap would work better and save me more money. I will also make a 3" or 6" thick panels using Rockwool Safe'n'Sound. Couldn't find any OC703 in local stores and online shopping has too much shipping cost.
 
eyeballing said:
Is it the pipe insulation DIY one? I know just bags of insulation would be as nice as the well made cylinder bass trap, but do you think it would still help in small room? Mine is 12' x 10' x 8'
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To clarify the cylinder trap is called a tube trap. There are ones that are sold on the market but basically if you roll the insulation into a tight tube shape and place it in the corner it will help with the bass build-up in the corner. You can also place them in other parts of the room so they act like a mid band or high absorber. The principle is similar to the principal that if you put speakers in a corner the bass response comes up (no always a good thing) so placing the tube into the corner reduces bass build-up in the corner. True it should not be referred to as a bass trap, but it can still help with room bass problems.

I suggested this solution to a friend of mine who was in a rental and did not want to build something that would have to be removed when he moved out later, the tube traps can be picked up and taken with him.

Alan
 
witzendoz said:
To clarify the cylinder trap is called a tube trap. There are ones that are sold on the market but basically if you roll the insulation into a tight tube shape and place it in the corner it will help with the bass build-up in the corner. You can also place them in other parts of the room so they act like a mid band or high absorber. The principle is similar to the principal that if you put speakers in a corner the bass response comes up (no always a good thing) so placing the tube into the corner reduces bass build-up in the corner. True it should not be referred to as a bass trap, but it can still help with room bass problems.
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I know acoustics differs every room and every sound, but do you have any rough idea of which would work best just for sake of low end below 300hz: stacked wrapped fluffy insulation, DIY soffit using same fluffy insulation, or the tube trap you mentioned? and do you know what material people would usually use for tube trap?
 
I am not talking fluffy insulation, you need dense insulation. If you go to an industrial insulation supplier, you can buy large pipe insulation that is very rigid. You can then stuff some softer insulation inside. Or you can roll some insulation tightly into a tube.

Alan
 
witzendoz said:
I am not talking fluffy insulation, you need dense insulation. If you go to an industrial insulation supplier, you can buy large pipe insulation that is very rigid. You can then stuff some softer insulation inside. Or you can roll some insulation tightly into a tube.

Alan
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Oh sorry if I wasn't being clear. I was trying to compare soffit bass trap using fluffy insulation against rigid pipe insulation. Or were you saying it is better to use denser material for both? Sorry English isn't my first language.
 
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