Question for Ethan

Posted: Wed Mar 30, 2005 9:15 am

Ethan
I'm Modeling my Studio and I'm planing to mount some 705 fiberglass boards at the corners. Where I'm living I can not get hold of OC 705. So I have made some research , Oc 705 has a Density of 90 kg/m3. Closest thing I find here is some rockwool boards with a density of eighter 70 kg/m3 or 110kg /m3
I'm confused a bit....
So which board should I pick for the corner traps 70kg/m3 or 110kg/m3?

Thanks

Posted: Wed Mar 30, 2005 1:01 pm

indraganzo,

> So which board should I pick for the corner traps 70kg/m3 or 110kg/m3? <

I've never tested either of those densities, but they're both close enough to 90 I'm sure either will work fine. The 70 is probably less expensive, so I'd go with that.

--Ethan

Posted: Wed Mar 30, 2005 2:59 pm

Greetings

I seem to remember Eric saying that a rule of thumb for rockwool is to use a lesser density than for fibreglass like the OC products.

Eric also mentioned that for corner chunks ( as opposed to thinner early reflection absorbers ) that a lower density is often better. ( You'll have to ask Eric for clarification on that )

I used 45kg/m3 Rockwool for my studio absorbers.

There's certainly no need for 70 or 110. IMO it's waste of money.

I would go for 45 or 60kg/3 stuff

Paul

Posted: Wed Mar 30, 2005 3:22 pm

Paul,

> Eric also mentioned that for corner chunks ( as opposed to thinner early reflection absorbers ) that a lower density is often better. <

Yes, as the material is made thicker you can get away with less density. Looking at the standard data at 125 Hz, thin panels benefit from higher density where thicker ones do not so much. This is also evident in my Density report, and more recent (unpublished) tests I did using very thick panels confirm this relationship further.

--Ethan

Posted: Fri Apr 01, 2005 1:50 am

Ethan and Paul
Thanx for the reply,

I have also an other question concerning the corner panels ;
I have found this industrial rockwool blanket in various density and thickness (from 3cm upto 10cm thickness and density 80 , 90 and 125 kg/m3) and I wonder ; instead of rigid boards can I use blanket type non rigid mineral or glass fiber? Confused

Posted: Fri Apr 01, 2005 11:17 am

indraganzo,

> industrial rockwool blanket ... density 80 , 90 and 125 kg/m3) <

With that density it seems more like rigid material than a "blanket." The only way to know if it's useful acoustically is to see the absorption data.

--Ethan

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