quadraphonic

[kwod-ruh-fon-ik] /ˌkwɒd rəˈfɒn ɪk/
adjective
1.
of, noting, or pertaining to the recording and reproduction of sound over four separate transmission or direct reproduction channels instead of the customary two of the stereo system:
a quadraphonic recording.
Also, four-channel, quadriphonic, quadrasonic
[kwod-ruh-son-ik] /ˌkwɒd rəˈsɒn ɪk/ (Show IPA)
.
Origin
1965-70; quadra-, variant of quadri- + -phonic, as in stereophonic
Examples from the web for quadraphonic
  • It begins with a chaotic soundscape of voices and percussion on quadraphonic tape.
  • First there was mono, then came stereo, and for awhile quadraphonic.
Word Origin and History for quadraphonic
adj.

1969, irregular formation from quadri- "four" + phonic, from Greek phone "sound, voice" (see fame (n.)). The goal was to reproduce front-to-back sound distribution in addition to side-to-side stereo. The later term for the same idea, surround sound, is preferable to this.