[SDFish]

Has anyone compared acoustic foam to compressed fiberglass for use as room treatments?  If so, how did they compare?

Thanks

[Big Red Machine]

acoustic foam is very limited in the frequencies it can attenuate.  There are tables somewhere to show you the comparisons.  Much better off with 703 or 705 if you are serious.

[bpape]

Even 'good' acoustic foam is far inferior to compressed fiberglass, mineral wool, or acoustic cotton.  Most foam products of comparable thickness will be considerably less effective as effective below 500-1kHz depending on thickness - which is where most rooms require additional control.

Just a comparison - coefficients at 125, 250, 500, 1k, 2k, 4k

2" Auralex foam
0.11 0.30 0.91 1.05 0.99 1.00


2" OC703
0.17 0.86 1.14 1.07 1.02 0.98

2" 3lb density acoustic cotton
0.35 0.94 1.32 1.22 1.06 1.03

Note the differences from 500Hz down (1st 3 figures for each product)

As you get thicker, the differences are even more pronounced.

Bryan

[low.pfile]

Bryan
So the higher number means more attenuation of that frequency?
(maybe the wrong term)
Is a higher coefficient better?

[bpape]

All else equal - yes - higher numbers mean more absorption at that center frequency.

Also, when you consider the price of OC703 vs the price of the 2" Auralex, the 703 is performing better for less money.  The cotton is a bit more but the performance is outstanding.

Bryan

[low.pfile]

Thanks for the info Bryan!

[drphoto]

It's sort of crazy what people charge for that foam stuff. You can't beat GIK for the performance/price/quality of build.....and fast turn around for custom colors. I could have maybe saved a few absolute dollars if I'd gone DIY, but I value my time too.

And I think the panels look a lot nicer than a bunch of Sonex too.

[mfsoa]

...and don't forget GIKs outstanding customer service and advice. They don't openly treat their audiophile customers as delusional sheep like some acoustical treatment companies. 

I have also bought from bpape directly (Green Glue - thanks Bryan!) with the same top-notch service and low prices.

Two thumbs up!   

-Mike

[Ethan Winer]

Has anyone compared acoustic foam to compressed fiberglass for use as room treatments?  If so, how did they compare?

I'm not one to usually defend foam.

Good foam (ie: Auralex, not Foam By Mail and Foam Factory etc) absorbs similarly to rigid fiberglass of the same thickness. The reason most foam seems to spec worse is because it's not usually made as a solid slab. For example, 2-inch thick foam is two inches thick only at the points or peaks, depending on how it's sculpted. If you took two pieces of sculpted foam and nested them face to face, then the foam really would be two inches thick throughout. And then it would absorb about the same as rigid fiberglass.

That said, it's not our fault that foam companies choose to cut out half of the material to make a pretty pattern!

--Ethan

[bpape]

...and don't forget GIKs outstanding customer service and advice. They don't openly treat their audiophile customers as delusional sheep like some acoustical treatment companies. 

I have also bought from bpape directly (Green Glue - thanks Bryan!) with the same top-notch service and low prices.

Two thumbs up!   

-Mike

You gotta remember I'm a delusional audiophile too!   

Bryan

[bpape]

I'm not one to usually defend foam.

Good foam (ie: Auralex, not Foam By Mail and Foam Factory etc) absorbs similarly to rigid fiberglass of the same thickness. The reason most foam seems to spec worse is because it's not usually made as a solid slab. For example, 2-inch thick foam is two inches thick only at the points or peaks, depending on how it's sculpted. If you took two pieces of sculpted foam and nested them face to face, then the foam really would be two inches thick throughout. And then it would absorb about the same as rigid fiberglass.

That said, it's not our fault that foam companies choose to cut out half of the material to make a pretty pattern!

--Ethan

Agreed.  But then, take double the price of Auralex foam to get that face to face performance and compare to the other products.  Makes some of the other options even more desirable IMO.

Bryan

[Ethan Winer]

You gotta remember I'm a delusional audiophile too!

We need to talk about that some day.

take double the price of Auralex foam to get that face to face performance and compare to the other products. Makes some of the other options even more desirable IMO.

Exactly.

--Ethan

[SDFish]

I see that fiberglass is better at bass absorption.  But if used to absorb reflections (i.e. not trying to absorb bass), how does the sound of the two materials compare.

[bpape]

It depends on what reflections you're talking about.  Even side wall reflections would be nice to get down into the vocal range (200ish Hz for deep male voice).

Rear wall reflections can be more critical in lower frequencies to prevent cancellations with direct waves from the front. 

Bryan