thank you for your reply tk
yes, before my friend build me my midibox seq i was using an mpc,on it there was a thing i liked that was;
on each track i was able to associate a program change, that pc made his job to change my patch on my synth when i started my pattern then it didn t change again when my loop cameback to the beginning, so i wa able to tweack button and my patch was not reinisialized at every beginning of the pattern,
i think it would be nice to have a the possibility to set a program change on each track without the need to put a pc on each step, or maybe it would be possible to configure it like a 0 program change don t change the patch?