as said before, qtractor does not currently "overdub" while on loop recording. what you record in the (N)th loop cycle is not played back on the next (N+1)th cycle.
instead, it can be set to create "takes" from each loop cycle (loop recording mode option). that is, you get N "takes" and then select which one is the one to playback.
otoh. "overdubs" can only be made by recording a second time around, creating a newer clip that may well overlap any previously recorded or existing ones which are played-back as usual while current recording is engaged.
note that overlapping clips are played-back simultaneously as if they were "overdubbed". later you can optionally merge those overlapped clips into one real "overdubbed" clip.
yes, i know that's all a gang of multiple steps to perform what should be simple action as you ask. but that's what you have, atm. :)
as said before, qtractor does not currently "overdub" while on loop recording. what you record in the (N)th loop cycle is not played back on the next (N+1)th cycle.
instead, it can be set to create "takes" from each loop cycle (loop recording mode option). that is, you get N "takes" and then select which one is the one to playback.
otoh. "overdubs" can only be made by recording a second time around, creating a newer clip that may well overlap any previously recorded or existing ones which are played-back as usual while current recording is engaged.
note that overlapping clips are played-back simultaneously as if they were "overdubbed". later you can optionally merge those overlapped clips into one real "overdubbed" clip.
yes, i know that's all a gang of multiple steps to perform what should be simple action as you ask. but that's what you have, atm. :)
cheers