How Pink Floyd Built a Quadraphonic Sound System When No One Else Had One

Before Dolby Atmos was a twinkle in anyone’s ear, Pink Floyd were trying to make a concert hall behave like a four-channel brain. In late 1969 they commissioned a custom quadraphonic PA system from engineer Charlie Watkins — basically four massive stacks of speakers arranged around the audience, each fed by a separate tape track. The idea was to physically place the listener inside the music, not just in front of it.

The key piece of hardware was the Azimuth Coordinator, a joystick-controlled panning device that let the sound engineer — usually the band’s longtime collaborator Alan Parsons, later replaced by Brian Humphries — steer sounds in a full circle around the room. During performances of “A Saucerful of Secrets” the helicopter noises would literally fly over the crowd’s heads. For “Atom Heart Mother” the brass section seemed to orbit the venue. This wasn’t novelty gimmickry; it was the band trying to make the spatial dimension of sound as expressive as pitch or volume.

The live effects beyond quadraphonics were equally obsessive. The band carried their own light show rig — oil wheels, slide projectors, black lights, and a 35mm film projector — all synced to the music via a click track. They even developed a system of coloured gels and strobes that responded to specific frequencies, so a kick drum could trigger a white flash. By 1972, when they began previewing The Dark Side of the Moon live, the quadraphonic mix was so precise that you could close your eyes and map the room’s dimensions just by the echo decay on a cash register sound.