Curved Air were briefly a sensation in the world of British progressive-rock because of Sonja Kristina's sensual vocals (a veteran of the "Hair" musical play) and Darryl Way's romantic violin. This was the same combination tested in California by It's A Beautiful Day. Francis Monkman (the real genius behind their compositions) added a synthesizer. Air Conditioning (Warner, 1970) boasts Vivaldi, their most celebrated piece.