Gearslutz.com - View Single Post - Owen Corning 703 or subistitue in Canada?

danbronson · 23rd April 2008

Ack! Okay, I read through the thread. You weren't kidding, it's not intuitive. But I think I have a much better understanding now, especially thanks to the Porous Absorber Calculator (the excel spreadsheet).

So correct me if I'm wrong, but the thicker the absorber and air gap, the lower the frequencies you can absorb BUT as those factors change, the ideal absorber changes as well. Looks like for 6" thick with a 6" air gap behind, something with a gas flow resistivity of 6,000 rayls/m is ideal. That's not much at all! In fact, it seems to me that fluffy fiberglass might be pretty close to that.

Any idea how I can calculate the gas flow resistivity of different Roxul products to determine the ideal one?

23rd April 2008	#5
danbronson Lives for gear Joined: Feb 2008 Location: Calgary, Alberta Posts: 871	Ack! Okay, I read through the thread. You weren't kidding, it's not intuitive. But I think I have a much better understanding now, especially thanks to the Porous Absorber Calculator (the excel spreadsheet). So correct me if I'm wrong, but the thicker the absorber and air gap, the lower the frequencies you can absorb BUT as those factors change, the ideal absorber changes as well. Looks like for 6" thick with a 6" air gap behind, something with a gas flow resistivity of 6,000 rayls/m is ideal. That's not much at all! In fact, it seems to me that fluffy fiberglass might be pretty close to that. Any idea how I can calculate the gas flow resistivity of different Roxul products to determine the ideal one?