Æther for string quartet and amplified difference tones. This is a drone piece in Just Intonation. The instruments are processed by the computer to amplify their difference tones: pitches naturally produced which are the difference between the frequencies of any two pitches.
Performed on 10/31/12 by the Orava String Quartet on Pendulum New Music at the University of Colorado.
Video of the performance (unfortunately the audio is very quiet)