Hello Scottyee,

the PSR 9000 has NO serious polyphony problem. I have been playing it since end of November 1999 and I have not found any problems regarding polyphony.
Some explanations: it is true, that the PSR 9000 can run out of the 126 polyphony (and it happens sometimes, it depends how you play). As Shakil explained, one waveform (instrument) can use up to 8 waves. I have not found such a instrument. Some of panel voices use 4 waves, the rest less than 4.
You should be awake, that if you layer three instruments with 4 waves, play a full chord with both hands and turn on auto-accompaniment, it will sure run out of the polyphony, but what keyboard will not??

In my repertoire I have only two or three songs, where I should pay attention during playing, otherwise some instrument will be muted. And I use On Bass Pro accompaniment, always Left Hand instrument, depending on the song up to three instruments for the right hand and sometimes Multi Pads.

Regards

Marek