Hi Jim,
> Where can I get 703 rigid fiber glass? <
Besides what I've written here recently, see the Acoustics FAQ, second in the list on my Articles page:
http://www.ethanwiner.com/articles.html
> I know you want to sell me something <
ROF,L. Yeah, I know you all right.
My main goals are to help people, and to spread the word on the importance of acoustic treatment. If I only wanted to sell stuff I wouldn't spend my entire day helping people build their own acoustic treatment!
--Ethan