Credited for pioneering the use of tape loops and delayed signals as well as introducing musical repetition into Western music motifs, Terry Riley’s influence on prog rock and popular music can be heard pulsing from his 1967 offering, A Rainbow In Curved Air. Throughout the opening 18 minute and 39 second title-track, stroboscopic analog keyboards dot the sonic topography — similar soundscapes were later used in the Who’s “Won’t Get Fooled Again” and “Baba O’Riley” — which Pete Townshend titled in divided tribute to Indian mystic Meher Baba and Terry Riley. Although much of “A Rainbow In Curved Air” seems to recall early ambient music with its gossamer atmospheres and cyclical arrangements, it predated the genre by a few years. The same can be said for progressive rock — bands like Gong, the Soft Machine and Curved Air owe much to Riley, especially the latter, who took their moniker from this recording. The lengthier “Poppy Nogood and the Phantom Band” was scored for soprano saxophone and electric keyboard. Here can be heard Riley’s improvisational tape manipulations, changing pitches and tones while suspended in mid-note.