Was the Helicopter Sound in 'Sheep' a Real Recording or Synthesized?

It’s a real helicopter. Pink Floyd recorded a helicopter flying around Battersea Power Station at night, using a binaural dummy head microphone placed on a tripod. The recording captured the Doppler effect of the rotors as the helicopter circled the building.

The band then tweaked the tape speed and added reverb in the studio to match the track’s key and mood. So while the source is authentic, the final sound is subtly processed — a perfect blend of field recording and studio manipulation. The recording session for the helicopter happened in early 1976, separate from the album’s main tracking at Britannia Row Studios.