Something like 20 years ago I heard a radio programme about Die Kunst der Fugue (JS Bach), and I was inspired to write short music where to voices in double/half tempo, the fast part playing twice. Quite a fun, almost mathematical conondrum. In my case the slow part was the upper part. I think that is a good idea, as it's often easier to hear the melody in th upper part, and the slow version is harder to hear as a melody. Having it both slow and in the lower part can make it harder to "hear". I've been trying to write fugual music lately ... or more like a fughetto I guess. I'm not to concerned about following all kinds of fugue rules and convensions strictly. It can be quite hard, but it's fun and rewarding!
That worked really well! I wonder how it would work if the augmentation was in the treble part. My suspicion is that the piece would seem to drag more. I'll have to give it a try.
I'm curious about how well this method extends before things get distressingly complex... how about three voices, the 2nd in augmentation and the 3rd in diminution (and maybe at the 5th?) I appreciate that doing that for the piano would introduce an additional set of considerations (i.e. what is physically playable) that might put it beyond the scope of a 15 minute demonstration, but it would still be fun to see.
