jhs@mitre-bedford.ARPA.UUCP (02/17/87)
Brad: No, I don't think I saw ARC for the 8-bitters. Would appreciate a copy. I don't know how I missed it, but I did. Glad you liked the random music generator. It shouldn't be hard to play around and find even better algorithms for note/chord selection. The present version which uses small steps up and down is far more musical-sounding than the first attempt, which picked the notes at random. The construction of chords was very ad hoc, the key (so to speak) point being that all the available notes are half-tones in the tempered diatonic scale (translation, all frequency ratios are powers of the twelfth root of two). I experimented and found that the rules for picking steps to make a chord that I have in the program sounded pleasant, so that is where it rests. Much improvement is doubtless possible. I think the best addition now would be some logic that remembers runs of notes and throws in repetitions of one or more of them. Maybe four memories for sequences, and let it pick the length and the sequences at random, but multiples of 4 notes in a sequence (in 4/4 signature). Then assign some different probabilities for starting a repeat. You could even impose patterns like having one of the sequences always show up as a "chorus" the end of each "verse" or whatever the correct terms are. Might also throw in a rule or two to make the final chorus end up on a "tonic" chord, meaning you would have to pick a key -- or the program would, at any rate. -John S.