I forgot that Qtractor treats all midi tracks that share a channel as if they were one. If you make a change to the properties of a track it will be applied to all of the same channel (logical behavior on the other hand).
Since SF2 manages libraries (not just an instrument) it supports channel information.
This allows you to make a multi-instrumental arrangement with a single SF2 and different midi channels.
As I understand it (I could be wrong) SFZ, when managing a single instrument, does not need to read channels. It doesn't matter to him because he can only play the loaded instrument. It cannot change another, because there is no other.
I recommend you always do it from the track properties, because it works the same for virtual synths and hardware synths. Especially if you work with GM libraries and synth with GM support, since it will be very easy for you to exchange more or less equivalent sounds without changing the session settings.
I'm glad you found the solution.
I forgot that Qtractor treats all midi tracks that share a channel as if they were one. If you make a change to the properties of a track it will be applied to all of the same channel (logical behavior on the other hand).
Since SF2 manages libraries (not just an instrument) it supports channel information.
This allows you to make a multi-instrumental arrangement with a single SF2 and different midi channels.
As I understand it (I could be wrong) SFZ, when managing a single instrument, does not need to read channels. It doesn't matter to him because he can only play the loaded instrument. It cannot change another, because there is no other.
I recommend you always do it from the track properties, because it works the same for virtual synths and hardware synths. Especially if you work with GM libraries and synth with GM support, since it will be very easy for you to exchange more or less equivalent sounds without changing the session settings.