Quote Originally Posted by dr. d View Post
... then came the quad...
For a while, I saw some LP selections in quad when I was young, but the hardware to produce and play them back were just too expensive so it didn't gain enough traction. Most consumers only had stereo-capable equipment for LP, mini-cassette, 8-track, etc.

Anyway, quadraphonic was eventually revived and evolved to become the surround sound as we know them today.