A note about polyphony...
My experience with Audya since 2009, taught to me that Audya series not need too much polyphony... Why??...
Because a very important channel (as is the Drums), it's a simple audio file and not Time slices that need midi key mapping to play, but its a simple wav file (as is a simple Song Wav File) and play with Time Stretch method directly from hard disk...
Therefore a very important channel as is the Drums, which requires more polyphonic, here not need polyphony to play...
The Audio Guitars, and Grooves play with Time Slice method (one or 2 bars)....
And dont forget that the Pa4x, and also Tyros 5 that its 2 tipycal Midi Arrangers, have 128 notes polyphony... In addition dont forget that Pa4x, can to use up to 128 Voices and up 128 Oscilators... However the Pa4x, play very good (in styles and play parallel) without any problem with polyphony.... I have here a Pa4x and I know that...
Dont forget also that, Ketron use per in voice up to 4 velocity layers and not all voices is with multilayers, (maybe in SD9PRO will have up to 6 velocity layers -- I mean GM voices and not Sounds/Programms that its Combinations of voices, and it not play in styles)....
Therefore the GM voices of Ketron is very simple and very (FRIENDLY) in polyphony because too many voices is 2 or 3 velocity layers and Drums is a simple wav file without polyphony...
How many time we use 48 parts??.. Mayde in a midi file??.. If I have a part with 48 parts in a midi file, I convert to MP3 and I play from there or 5.1 Suround file (stems group) to have different control volume....
Each style need as we know (Drums (Audio Drums here that not need polyphony),Percussions, Bass, and 5 Channels Chords... Its very simple in styles here....