In the 1970s, it looked like a quadraphonic sound system would be a lot better than stereo.
From the toledoblade.com
Columbia introduced a quadraphonic matrix system, SQ, which required a decoder, 4-channel amplifier and the four speakers.
From the en.wikipedia.org
Quadraphonic sound was a four-channel reproduction system, which is considered to be the origin of surround sound.
From the en.wikipedia.org
They also purchased extra equipment, which included new speakers, a PA system, a 28-track mixing desk with four quadraphonic outputs, and a custom-built lighting rig.