NEED INFO: Source for buying Speaker Foam/Rubber SURROUNDS ?

If anyone knows of an OEM where you can order quantity butyl rubber or
foam surrounds for repairing woofers, please email .
Already know about Parts Express, but expensive and no real quantity
discounts. Esp interested in finding a source for the butyl rubber
surrounds in various standard sizes (6.5", 8", 10", etc). Thanks for
any help!