Here's an interesting thread about CD-4 translated with Google translate.
http://translate.google.com/transla...X&ei=8t8RUI-RDMfL6wGsvYCACg&ved=0CEwQ7gEwATgU
also see
http://www.quadrophonie.de/englisch/index.html
http://translate.google.com/transla...X&ei=8t8RUI-RDMfL6wGsvYCACg&ved=0CEwQ7gEwATgU
also see
http://www.quadrophonie.de/englisch/index.html