Hi Nath
I've used various products over the years but more recently I've sourced a product called Quietwave from Acoustica.
The product is made in Australia and it's environmentally friendly if you're that way inclined.
Acoustic is located in Nelson St. Annandale. The same street that the Annandale Hotel is in.
http://www.acoustica.com.au/quietwave.htmlSome other varieties are Wavebar, Sonicbar, Acoustiblok
Wavebar is sold by Pyrotek
Work out the density you want... kilos per metre squared (kg/m2), then ring the various suppliers and get quotes.
It's usually sold in rolls but you might find a supplier that will sell you an offcut.
Hope this helps