Missed this Quadraphonic sound info during my quick pass view yesterday, which is on topic regarding playback, Pink Floyd, etc.
Live concerts Azimuth Co-ordinator used by Pink Floyd
Azimuth Co-ordinator used by Pink Floyd, made by Bernard Speight, 1969 (Victoria & Albert Museum, London)
In 1967 the rock group Pink Floyd performed the first-ever surround-sound rock concert at “Games for May”, a lavish affair at London’s Queen Elizabeth Hall, where the band debuted its custom-made quadraphonic speaker system.[20] The control device they had made, the Azimuth Co-ordinator, is now displayed at London's Victoria and Albert Museum, as part of their Theatre Collections gallery.[21]
http://en.m.wikipedia.org/wiki/File:...k_Floyd_VA.jpg