“Large Dark Wind Chime (Arab Tritone)”, 2008 by Klaus Weber.
“Optical Tone”, 2008 by Tsutomu Mutoh.
“Graphite Sequencer” by Caleb Coppock. Video. Graphite conducts electricity. Two wires brush against the surface of a paper disk as it spins. The wires are connected to a simple electronic tone generator. When a line of graphite is drawn across the disk, connecting the two wires, a tone is heard.
»Falling tone for 207 speakers« (2004) and »230 Unwanted Speakers« (2006) by John Wynne.