His quadraphonic sound system was the envy of all his mates.

Four speakers

Quadraphonic systems used 4 speakers and reproduce music mixed with 4 independent channels. Unlike surround sound, Quadraphonic systems do not have a separate subwoofer channel, nor do they have a front center channel. They reproduced music from Quadraphonic 8-track cartridges, Reel-to-reel players and phonograph players which were made for the purpose.

Quadraphonic

Stereo is in fact short for Stereophonic, meaning 2 sounds, Quad is 4, making Quadraphonic 4 sounds using the same naming convention.

In new speak it is 4.0 surround

quadrophenia