Fiberglass or mineral wool better for corner basstraps?

A

aevarr

New member
Hi all. I've been planning to make some corner bass traps for my home studio. I'm following a design where you make triangular pieces of thick rigid fiberglass (or...) and stack them in the corner. So basically, cover the whole corner of the room with the stuff.

Now the question arises, which one is better for killing the low bass frequencies:
some rigid fiberglass (I suppose this Finnish stuff I'm planning to buy is that, it's "glass wool" but in stiff panels), or mineral or rock wool panels?

I have heard that rigid fiberglass would be better when it's lighter, and if it's heavier (weighs more per m^3) then mineral or rockwool would be better?

The fiberglass that's available for me weighs 17 kg / m^3 and is 15 cm thick (although the thickness doesn't matter in this design really or does it?). Do you think that would be sturdy enough to kill low bass? Does it have to be this 40-50 kg / m^3 stuff to be effective? Is the heavier wool _the_only_way_to_go_?

Thanks for all your expertise here.
 
My conversion hat is in the shop for repair...

Anyway, with a solid chunk type absorber, you can use lighter materials. Use what you have available to you. Something on the order of 3lb/cu ft will work well and save you some money.

Now, if you were just straddling the corner, then I'd say use either 6" of 3lb material or 4" of 8lb material in which case 8lb mineral wool is more cost effective.

Bryan
 
That heavy, really?

Hi, thanks for your feedback, Bryan. My conversion hat came up with these calculations:

3 lb / ft^3 = 48 kg / m^3

8 lb / ft^3 = 128 kg / m^3 (!)

Are you sure it has to be THIS heavy? I mean, the rigid fiberglass panels I was looking at were 17 kg / m^3, so there's a huge gap there... Or does my conversion hat need some repairing as well?
 
Yes. That appears to be correct. 17kg looks to be about 1lb/cu ft. If you're doing it solid and it's thick enough, it will still work OK. I wouldn't try it only 4" thick or so.

Bryan
 
Twice I have designed bass traps with higher density fibreglass boards (.= or > than 6 pcf) and got bad results. Maybe there were other factors….

BRYAN, what’s your opinion? Also, when you say “solid traps” do you mean filled all the way to the wall? Do they perform better than the “empty” ones?
Thanks
Mike
 
You must log in or register to reply here.
Back
Top