I tried some chords muting bass and drums, keeping only chord patterns, and it seems many of them are handled by audio loops (you get different patterns depending on the type and also the tonality of the chord you play, this gives a really "live" feel on the music.
But... I had the impression that playing strange chords the audio parts are completely muted and only the midi parts sounds. When I'll have the audya at home (perhaps next weekend), I'll do extensive testing on this.

However playing normally this arranger is impressive, with a good speaker system you think you have a live band playing around you.... As I told before... right hand voices could be much better however... The best could be playing T3 voices with right hand along with Audya arranger parts... but... hey... I ain't going to spend 6500 euros for that!!!!!!