Hi BogdanH. I must tell you, maybe I mixed up this problem by my self. We have sextet, I play keys, two guys with Les Paul guitars, drummer with ALESIS e-set and singer girl with tambourine. OK. I usually use KORG Pa800 and ROLAND E-80 + YAMAHA SY77 on my rack. I bought PSR-S700 2009, very little use, so I cleaned dust and connect it PA all was OK. I usually use split: left picked organ etc. right side right1 - right2, voices, I play left chords and right solo voices. It was easy to choose OTS voices on fly, accompaniment doesn't start while playing, but now, I started to play as usual, when pick OTS, suddenly accompaniment started, I'm surprise what happened! I did Initializing system setup, no help.
Regards Pertti from Finland