Is it possible to set C3 as master so that I can see the tempo on my external keyboard also?
You need to select the MIDI devices that receive MIDI clock in the MIDI port settings. Then Cantabile will send MIDI clock out through those devices.
BUT: C3 will only send clock when the master transport is running, not while it is stopped. So if you want to sync an external device, you’ll need to start the master transport at the beginning of a song, at least for some seconds until the tempo “sticks” with your keyboard.
If you’re playing backing tracks from master transport, this is easy; for my songs that require tempo info (syncing the delay on my external VoiceLive), I just use a “song-onLoad” binding that starts master transport and stops it again after three seconds.
The easiest workaround would be to simply start master transport at the beginning of every song (via a song->onLoad binding) and simply leave it running. Doesn’t really hurt…