As an alternative to the wide frequency range of the first Bobby Fischer piece, I decided to try using the dual-tone multi-frequency (DTMF) strategy employed by the touch tone telephone.
Each button on the telephone plays two tones at once, so only eight frequencies are required to encode sixteen buttons. (The phone is designed for sixteen buttons – the twelve you find on most phones, plus A, B, C, D buttons, but these extra four buttons are rare.)
So, if you had a sixty-four button telephone, you could get by with sixteen frequencies. I created two eight-tone octaves, and used one on the horizontal rows and one on the vertical columns. The two tones are combined to give each square a unique sound.
The rules are the same as the first piece, each move results in two notes, one for the starting square and one for the ending square. I played with different pauses between the moves, but the one with no pause ended up sounding the best to me.
I will probably use this as a starting point for a piece on Music For The Monsters, and will layer in other sounds to complete the sketch.