quadraphony

[kwo-draf-uh-nee] /kwɒˈdræf ə ni/
noun
1.
high-fidelity sound reproduction involving signals transmitted through four different channels.
Also called quadraphonics
[kwod-ruh-fon-iks] /ˌkwɒd rəˈfɒn ɪks/ (Show IPA),
quadriphonics, quadrasonics
[kwod-ruh-son-iks] /ˌkwɒd rəˈsɒn ɪks/ (Show IPA),
quadrisonics.
Origin
1965-70; quadra-, variant of quadri- + -phony
British Dictionary definitions for quadraphonics

quadraphonics

/ˌkwɒdrəˈfɒnɪks/
noun
1.
(functioning as sing) a system of sound recording and reproduction that uses four independent loudspeakers to give directional sources of sound. The speakers are fed by four separate amplified signals
Derived Forms
quadraphonic, quadrophonic, adjective
quadraphony, quadrophony (kwɒdˈrɒfənɪ) noun