Density about fiberglass panels

[IzzyRock]

Hello,
I started the thread "Building some bass traps, check 'em out ", but since this is an specific question, I must create a new thread . Hopefully Ethan or Glenn could help me out here.

My problem is the following:

I bought low density fiberglass panels, without knowing they were 18kg/m3 (like 1.4 pcf)
I already put those panels inside 3 frames (out of six) but even tho, i'm gonna make a few calls asking if i can find more denser panels here in Chile, i dont mind taking them out if they totally wont work.

Now..
I was seeing some absorption charts, and the diference from 18kg/m3 to 60kg/m3 is not that radical, it only improvees a few . The numbers only raise up a lot from panels of 90-100kg/m3 and above

So..
Can I still use them? Or I better buy the denser panels i can find here?
Obviosly i know the answer. The denser the better. BUT, Can I still use the 3 panels i already made for the sidewalls and get thicker fiberglass for bass trapping? (So i dont completely lose the money i put on the fiberglass panels i bought)

THanks

PD: The panels i bought are 2" thick 18kg/m3. So the idea is to buy 2" thick as well , but denser

[Glenn Kuras]

Obviosly i know the answer. The thicker the better. BUT, Can I still use the 3 panels i already made for the sidewalls and get thicker fiberglass for bass trapping? (So i dont completely lose the money i put on the fiberglass panels i bought)

Oh yea if they are 2" or more thick then yes use them for the early reflection points. They will work pretty darn well for that.thumbsup



Glenn

[IzzyRock]

Thanks Glenn.
I noticed from 400hz and up the absorption numbers doesnt really change from really low-density panels. Its in the low end that it does really change. So thats what i thought. (All frames are 4" thick)

[Ethan Winer]

Originally Posted by IzzyRock

I bought low density fiberglass panels, without knowing they were 18kg/m3 (like 1.4 pcf)

Thanks for moving this to the forum.

Glenn gave you the correct answer. That stuff will work for bass traps too, and in that case you'll do better to make the traps six inches thick if possible. But even at four inches thick they're work.

--Ethan

[IzzyRock]

Thanks

I found 100kg/m3 panels today. and i might be buying some for the remaining frames

[RCM - Ronan]

Speaking of density, I was putting some treatment ideas together and I started thinking about mixing and matching 705 and 703. (4 inch traps made from 2 inches of 703 + 2 inches of 705) I am not sure I have seen this done and wondering if there are pros and cons for that.

[avare]

Originally Posted by rcm

Speaking of density, I was putting some treatment ideas together and I started thinking about mixing and matching 705 and 703. (4 inch traps made from 2 inches of 703 + 2 inches of 705) I am not sure I have seen this done and wondering if there are pros and cons for that.

There is no advantage to it. 2" of 705 2" from a surface will give roughly the same absorption as 4" of 703.

Andre