Sound Deadening Board - Homasote

I've read through ALOT of info on this site and haven't really seen too much - if any - info on Sound-Deadening Boards -such as Homasote. http://www.homasote.com/sb.html Has anyone used any type of board like this in their studios and if so what kinds of STC results have you reached? Homasote says in their PDF http://www.homasote.com/Installation/Ho ... lation.pdf that you can get an STC rating in the 60's with a double-wall constuction. Now this stuff goes for around $16.75 per 8'X4' sheet. Any thoughts people? Thanks So Much, - Brad

Yeah, don't waste your time - an extra layer of gypsum wallboard costs about half that or less, and has more mass; it's also simpler to build with less chance of tearing out at screw locations... Steve