Hi Fred,
Thanks for your answers. (sorry for my late reply...)
Registrations doesn't fit totally or maybe I have to create one for each behaviour.
The accompaniment is stopped manually by pressing my second switch Pedal.
A cappella words are singing during few seconds.
Then, I need to relaunch the accomp with a Drums breaks fill JUST BEFORE restarting the theme with the Chord Looper.
Chord Looper Is starting as soon as the measure is started even if we have chosen a Drums break fill (for intro) initially.
I think there is no really easy solution except switching many times between registrations and manipulate carefully the stop/start, Drums films, activate CL manually.
Thanks for your inputs.
BR,
Toff