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Has anyone heard of Sonopan sheets ? I was at my local hardware dealer and was askng about rockwool , which he can get , then he said what about sonopan . He knows I am building a studio so that came to mind . He said he has sold it to radio and TV stations . I looked it up on the NET and it looked very good . If John is watching in here maybe he can give a little input on this . IF you go to this URL http://www.cascades.com/pdf/brochure_sonopan_en.pdf and go to page 3 you will see how they use ti to get an STC rate of 68 in a double wall construction . It says on the website that it is inexpensive . I am getting a price on it as I am writing this . When I find out I will post it.
Jim