Owens Corning, Johns Manville, Ruxul (?) ... the important thing is the density but here's the link:
http://www.youtube.com/watch?v=iyYUpkpL0gw
There is other related stuff to watch in the side bar but here's the video:
Google: Owens Corning 700 Series pdf
The first result will get you to the Sound Absorption Coefficients of 703 and 705 Plain which are the ones to get. The 703 is half the weight and from what I understand almost as effective at the lower frequencies that are not covered in the calculation of the NRC.
This is the Ready Acoustics 'bag' solution:
http://www.readyacoustics.com/index.php?main_page=index&cPath=26_11_2
That's for Walter who was looking for something to do with 4 pieces of 703.
Walter, get two 4" bags and call it a day.
Sorry for the threadjack.
