AURAL INNOVATIONS
Originally a print magazine in the 1990s, AI is now the web's go-to place for Spacerock. Many wonderful things on this site thanks to Jerry Kranitz.
RECORD OUTLET
Excellent record store in Thousand Oaks, California
The website is little more than a billboard, but the store itself has a good selection of Vinyl, used CDs, cassettes and even 8-tracks as well as acessories and repair service.
4CHANNELSOUND.COM
Tab Patterson's site focuses mainly on matrix quad discs and has many pictures of quad equipment.