The Tate Modern’s online archive is a wealth of sound-related material. The site’s homepage recently linked to a series of performances of music by Alvin Lucier from September 2005, including four pieces and a load of associated materials, which together are titled Alvin Lucier: Open Sound Systems.
“In Memoriam Jon Higgins for solo clarinet” (1984) tracks over the course of its 20 minutes an ever-rising pitch performed by clarinetist Andy Harper, who plays against an “electronically generated pure wave” (MP3). “Silver Street Car: For the Orchestra: solo triangle & microphone” (1988), its title lifted from a Surrealist text by Luis Bunuel, is a piece of microscopic intensity, performed entirely on a single triangle, a 15-minute expanse of lightly tapped beats played by Ross Parfitt (MP3). “Opera with Objects” (1996) is all clicks and clutter, performed by the composer (MP3). Along the lines of the “Higgins” pieced, “Wave Songs for solo soprano” (1997) has a singer (Juliet Fraser) pitched against a pair of pure wave oscillators, allowing for light beading (MP3).
Also available for download are the score for the “Higgins” and the score and Lucier’s notes for “Wave Songs,” plus rehearsal recordings for all but “Opera with Objects,” in which you can hear Lucier giving advice to the performers. More info at tate.org.uk.