Hi there (especially Ethan!)

I'm looking at two types of materials.

Partly to sit against a portion of the adjoining wall that's covered with screen and curtains, as seen here...
http://www.avsforum.com/avs-vb/showthread.php?t=1117258
(Can't fit more than 50mm behind the screen.)

... but mostly to build at least one floor-to-ceiling bass trap for the front-right corner (90cm wide, 240cm high, and at least 88cm thick).

One option is a Rockwool batt that's rated at 48kg/m3...
http://www.bradfordinsulation.com.au/Pro...s-internal.aspx
also... http://www.ascentonline.com.au/html/prod...insulation.html

The other option is a Glasswool batt that's also rated at 48kg/m3...
http://www.bradfordinsulation.com.au/Products/Commerical/HVAC/Ultratel.aspx
(Data sheets for each are available at the top-right of their pages.)

Which will offer the best absorbancy, and how would they compare to a 48kg/m3 fibreglass, which I'm wanting to avoid handling?

Cheers.

I don't have time to go through all the numbers of every product you listed, but the product that has the best low end test numbers will do the best for bass trapping. Keep in mind though that if one has a number of say .90 at 125 hz and another is say .85 at 125 hz, you can pretty much bet they are pretty equal. So at that point I would just shop on price and or ease of building.

Exactly.

Cheers.
One reason I ask is that I've read that Rockwool or Glasswol generally need to have double the mass of fibreglass to be as effective, although that doesn't seem to ring true.


For the record, I've also found a very dense (and probably rigid) 60kg/m3 rockwool batt...
http://www.bradfordinsulation.com.au/Products/Commerical/HVAC/Rockwool-Duct-liner.aspx


Better still, here's a white, polyester batt that seems pretty much ideal...
http://www.acoustica.com.au/hdbatts.html

* Polyester, so no flaking or irritation
* Available in 50mm, 75mm and 100mm thicknesses
* Available in 48kg/m3 - up to 180kg/m3 !
* White
* Two (or more if layered) 1200 x 600 batts would make a floor-to-ceiling bass trap.
* Available with foil backing
* Pretty cheap - around AU$15 a square metre

That 180kg/m3 density should be somewhat rigid, methinks!!!

Thanks again for your time and patience.
A few more basic questions, and I think I'm done...

The first thing I want to do is to make two stacked 1200mm-high, floor-to-ceiling corner traps for the front right. Again, here's the room...
http://www.avsforum.com/avs-vb/showthread.php?t=1117258

I want to make it 900mm wide, so it'll go from the curtain at the front to the curtain at the side wall.

I could either....

1. Stack up a series of triangles to make a Toblerone shape.

or

2. Make two pinewood frames and add one or two layers (?) of 75mm (?) 48kg/m3 (?) polyester batts.

Other additions, like material and perhaps painted plywood (?), would follow at a later stage.

50mm / 75mm thick, 48kg/m3 batts with no foil backing are the cheapest. Here's the preferred batt material again...
http://www.acoustica.com.au/hdbatts.html

But 100mm thickness is also available, and densities of up to 180kg/m3.

Is it worth my while getting anything more than 75mm / 48kg ?

Reducing bass boom is the goal. No great desire to affect the higher frequencies.

48 kg/m3 is fine, and a "Toblerone" shape (great analogy!) is also best. So make the front face as wide as you can manage, and it'll work great.

--Ethan