Polyurethane Foam for Bass trap?

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sevenways

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Dear All,

I would like to get advice from you to do DIY bass trap and panel absorbers.
I know rigid-fiberglass is the best for bass trap but I can't find rigid-fibreglass in my region anywhere, only I can get is very soft 2" normal fiberglass but it has silver foil (image 2) and I think it can't use for bass trap. But I can get polyurethane foams (image 1) in different densities and different thckness in my place.

So my question is, can I use polyurethane foam as my bass trap or panel absorbers? As I can get in different densities and tickness, I'm thinking about very dense foam with 4" thick for low freq. and normal dense foam with 2" thick for mid and high freq. Are they usable?

Thanks,
Sevenways
 

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Hi,

I am assuming that the foam you are talking about is simular to what you would find in furniture, mattresses etc. If that is the case the answer is yeas it will work. However it will work a little different to the fibreglass if trying to calculate what will happen.

If the foam is solid like they put in cool room walls this will not work.

If you are trying to build a bass trap, if you pack the foam hard into a corner of the room it will act as a bass trap, however it will also reduce high end frequencies due to the foam surface, if you want to keep the high end, cover the foam with a thin wood panelling. The panelling will reflect the highs but let the bass travel through and become trapped.

Foam is not the best thing but if you can get it easy and cheap give it a try.

Cheers

Alan.
 
I would think you'd be better off putting bales of insulation in the corner.
 
witzendoz said:
Hi,

I am assuming that the foam you are talking about is simular to what you would find in furniture, mattresses etc. If that is the case the answer is yeas it will work. However it will work a little different to the fibreglass if trying to calculate what will happen.

If the foam is solid like they put in cool room walls this will not work.

If you are trying to build a bass trap, if you pack the foam hard into a corner of the room it will act as a bass trap, however it will also reduce high end frequencies due to the foam surface, if you want to keep the high end, cover the foam with a thin wood panelling. The panelling will reflect the highs but let the bass travel through and become trapped.

Foam is not the best thing but if you can get it easy and cheap give it a try.

Cheers

Alan.
Click to expand...

Thanks Alan, yes the foam I mean is which mostly use in mattress.
I will make 4 bass traps for corners, my plan is cover with fabric in front of 4" foam which place in 2'x4' wood frame.

As you said it will also absorb high end, I don't know how to cover with thin wood panelling. Is there any DIY site for it? (or) if I don't cover with wood panel, it will affact to get good results? And also I would like to know what is the differences for using absorbers in Control room and recording room? Do I need bass trap in recording room too?

Sorry for my newbie questions.
Thanks,
Linn
 
Sorry, but I don't expect 4" of furniture foam to do much in the bass department. Absorbing some slap echo in the upper freqs is probably about the best you can hope for. I think some large chunks of that fiberglass stacked in the corners would be best.
 
sevenways said:
Dear All,

I would like to get advice from you to do DIY bass trap and panel absorbers.
I know rigid-fiberglass is the best for bass trap but I can't find rigid-fibreglass in my region anywhere, only I can get is very soft 2" normal fiberglass but it has silver foil (image 2) and I think it can't use for bass trap. But I can get polyurethane foams (image 1) in different densities and different thckness in my place.

So my question is, can I use polyurethane foam as my bass trap or panel absorbers? As I can get in different densities and tickness, I'm thinking about very dense foam with 4" thick for low freq. and normal dense foam with 2" thick for mid and high freq. Are they usable?

Thanks,
Sevenways
Click to expand...
I'd suggest searching harder for rigid fiberglass type material. Contact local insulation companies and ask if they've heard of it(maybe Rockwool, wineral wool, oc 703, etc). If you really can't find it, try and get it shipped. The $ is at its lowest for a long time, so buying from america is good just now.
 
Foam is pointless as a Bass absorber. Dont waste your time with it. Any type of insulation would probably do a better job.
 
Hi,

Well yes foam is not as good as ridged fibreglass but the question was that Sevenways did not have fibreglass available and that he had foam easily available. Foam is better than nothing at all, ridged fibreglass is better. High density polyester is even better still and it also has no harmful fibres, You do not even have to cover it, this is what I used throughout my new studio however it is more expensive.

If you google “bass trap” there are a thousand sites and also a thousand theories on building bass traps.

Cheers

Alan.
 
Thanks to all advice.
I still can't find rigid fiberglass though I can get regular fiberglass. But I will find info about shipping but I think it's very costy.
Btw today I got foam sample from a supplier.
One kind of foam is feel like fiberglass but it's just the combination of many foam pieces by glue. And when I squeeze it, it feel more solid than regular foam.
They said they have 4" thick of it.
In image, I compare with regular foam. It is the one with multi-color.
Any suggestion?

Thanks,
Sevenways
 

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invest in the rigid fiberglass. if not: the soft foam isn't going to work on anything except high frequencies. you could use small amounts of it (ensure its fire retardent) to break up echos on flat walls and ceilings by creating a 2-3 rows in a checkerboard pattern of 50mm x 60cm x 60cm squares covering about 25-30% of a given wall or ceiling (rough guideline). the denser (multi-color) foam (could be thick carpet padding - again it must be fire retardent and suitable for wall mounting) could probably be used as bass trap by layering it about 15cm deep in a frame and straddling it across vertical and horizontal corners. not nearly as effective as fiberglass but it will do something. you could probably also use that dense foam under several layers of 25mm MDF to create a drum riser (if you need it).

fire retardent is not an option - people get killed or severely hurt from fires every year in places in which untreated foam is a prevalent covering - its quick burning, produces toxic smoke = death or maiming.
 
Thanks for the advice Glenn!

gullfo said:
you could use small amounts of it (ensure its fire retardent) to break up echos on flat walls and ceilings by creating a 2-3 rows in a checkerboard pattern of 50mm x 60cm x 60cm squares covering about 25-30% of a given wall or ceiling (rough guideline).
Click to expand...

I'm really interested in that technique and so is for side wall treatments?
if you don't mind please tell me where can I find in detail? Is there any webpage or post which explain about it?

btw the multi-color foam is solid because it has some dry glue I think. They said they make it by glue-ing the small pieces of regular foam. So when glue are dry, they are solid. I would like to know those dry glue can affact to trap the bass?

Thanks,
sevenways
 
sevenways, understand your plight here, its tough trying to find materials sometimes to DIY here is a link for you, scroll down to soundproofing link

http://www.foambymail.com

these guys sell corner basstraps and studio foam very reasonable, maybe you could get it shipped and still come out okay.
 
Lectric_Lab said:
sevenways, understand your plight here, its tough trying to find materials sometimes to DIY here is a link for you, scroll down to soundproofing link

http://www.foambymail.com

these guys sell corner basstraps and studio foam very reasonable, maybe you could get it shipped and still come out okay.
Click to expand...
They have been shown to be liars. Stay away from them. You can get much better products from other sources. Keep looking for rigid fiberglass. Bpape(Brian) sells it, as well as acoustic cotton(probably better than rigid fiberglass), pretty cheap, so the only bad thing is shipping. But if you buy in bulk it should be fine.
 
It is just fancy-cut mattress foam once again. Whatever foam he found locally over there in "Asia" is probably going to be much cheaper than having FBM ship stuff out to him. Auralex isn't that much more expensive than FBM and is much higher quality. Yes I have used both.
 
Ethan Winer said:
Yeah, reasonable because it's crappy NON-acoustic foam. See this:

www.ethanwiner.com/fraud.html

The follow up here with any questions.

--Ethan
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Thanks for the heads-up on this company and their product. I feel bad recommending them now , as I've never actually bought anything from them it was a recommendation from a friend...guess he needs to get things right before sending me crappy information. Just trying to help...sorry.

btw....I did email him about this company.
 
sevenways said:
I'm really interested in that technique and so is for side wall treatments?
Click to expand...

take a look at Ethan Winer's site - look for the Art Studio page which he created along with Wes Lachot regarding positioning of treatments.
 
If you can't get rigid fiberglass, you can compress standard fluffy wall insulation (fiberglass) to achieve a higher density. It'll cost you more but it's way more effective than foam of any type.

Also, you may want to investigate mineral wool. That seems to be more readily available in many places where rigid fiberglass isn't

Bryan
 
bpape said:
If you can't get rigid fiberglass, you can compress standard fluffy wall insulation (fiberglass) to achieve a higher density. It'll cost you more but it's way more effective than foam of any type
Click to expand...


have a look at the link in my signature. This is exactly what I used for my broadband absorbers.

Sevenways, try looking at a building contractors shop for this type of stuff - look for something like acoustic loft insulator..
 
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