Video
Referring to the concert A above middle C, at a frequency of 440hz, a440 is considered by those who consider such things to be the reference frequency for the calibration of orchestral instruments–a pitch against which other pitches are compared and a reason why I will never be a professional trumpet player.
~90 exploits an unfortunate tendency to drift out of time. After making 90 recordings of hitting things with a mallet exactly 3 times every 2 seconds, I combined the recordings into pulsing textures. The phasing is me trying and failing to play in time.
Footage from a train in 2007, recorded on MiniDV tape. The sound is made from field recordings and instruments performed live into the Adding Machine.