quadraphonic

[ kwod-ruh-fon-ik ]
/ ˌkwɒd rəˈfɒn ɪk /

adjective

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, quad·ra·son·ic [kwod-ruh-son-ik] /ˌkwɒd rəˈsɒn ɪk/.

Origin of quadraphonic

1965–70; quadra-, variant of quadri- + -phonic, as in stereophonic
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019