The idea of 'generative' music is more involved than simply
'music generated by computers' or 'music generated by
algorithm.'
The basic
template for a piece of generative music is:
1. Set up a situation in which sound is produced without
human interference.
2. Set it in
motion.
3. Observe and record the results.
It's the ultimate
process-oriented music; as much concerned with
indeterminacy as it is with
algorithm.
While the trend now is to use
computers as
instruments for generative work, it's been done in the past with out-of-phase
tapes (by
Steve Reich), burning
prepared piano (by a few different
Fluxus artists), the
Aeolian Harp (by the ancient
Greeks, arguably the first deliberate automatic
music machine), etc.
Though I know this may read
pretentious to a lot of
skeptics,
Brian Eno said:
"I feel that with generative music, some people say, "Oh, well, the music isn't made by a human, so it's passionless," but actually it is made by a human. A garden isn't made by a human, but it's planted by one, you know? I feel that generative music means composing at that sort of metalevel of stepping back further and saying, "I'll specify the universe within which this music occurs and the sort of rules with which it will unfold, and then I'll be just like any other spectator and watch it happen."
He's also described generative music as being like a set of
wind chimes; constructed specifically by man but then
abandoned to produce music on their own, without intervention.
A few
composers who have made great works in this mode are:
John Cage
Gottfried Michael Koenig
Steve Reich
Max Matthews
Brian Eno
Terry Riley
Robert Rich