Many years ago I took an undergraduate course taught by Larry Bethune called "Rhythmic Ear Training", and the thing I remember most vividly from that class was the way Larry taught polyrhythms: He said it was necessary to learn to hear the
composite rhythm first before trying to figure out how to play the individual components. So, for example, if you're presented with a 4:5-tuplet, rather than thinking "uh, so each partial of the tuplet would be, um, 1.20% longer than a quarter note...er...wait..." you instead know that the combination of the four-against-five is going to go
"
BLAP, skee-bop, tick-tock, bonk-dee, bomp"
and then you just play your designated subset of that sound.
Okay, you had to be there...
