Concret PH is similar to what it must be like for a Clapton or Hendrix fan listening to Robert Johnson on a crackly 78: the sound is lo-fi but the elemental inspiration is otherworldly.
By 1962, when the 20-minute Bohor was completed, Xenakis' tightly-wound, creaking and clattering percussive electronic stew was reaching new heights of sophistication and well on the way to the sound of Persepolis. Bohor is the definite highlight here for me; fellow audio nerds might enjoy this little ancedote about the challenges of squeezing this kind of music into vinyl.
That's not all we get on the CD here, though: Hibiki-Hana-Ma (reverberation flower interval), composed for the Osaka Expo in 1970 and broadcast there on 800 loudspeakers, is a fascinating start-stop melange designed as cross-cultural celebration. Lastly, Xenakis' constant progress in mathematical compostion and computer programming threw up the utterly bizarre S.709 (1992-1994), sounding like Aphex Twin somehow managing to capture the sound of a released helium balloon flying around the studio.