Three improvisations by Brown on piano and live computer signal processing and Oliveros playing conch, percussion and her well-known accordion with expanded instrument system. Though I enjoy her writing immensely, a lot of Oliveros' previous music has left me cold. I'm happy to say that this is not the case here. This is a live recording of carefully played, well-reasoned music by two good listeners.

"Noctilucent Clouds" reminds me very much of AMM, with it's quiet piano runs and billowing notes from accordion and conch, and even a bit of what sounds like radio noise. Later on they get into a pumping on-and-off rhythm that builds into chattering bird-song, then stops and runs away on groaning electronics and street vendor accordion. Careful listening will be rewarded by the many small details here, and it's 17 plus minutes seem to fly by. "Gravity Waves" is much more electronic-laden, imitating frog chorus and insect life alongside the piano.

The final, 25 minute "Troposphere" begins with quiet crackle that could be water, or the processed sound of applause moving around the stereo picture. This brings up a point about the recording here, as the notes specify that the live processing was played through a quadraphonic system. The sound almost spins around one's head, but not quite. Oliveros' accordion takes on the sound of a string instrument one second and a psychedelic echo-organ the next, and the players shift emphasis so expertly that it seems to emanate from one entity, though in fact it comes from four very capable hands.