I am a classical musician and I use Ecasound for tracking only, which means recording live concerts on SD card. It is great application for that purpose because you can write a script and access the Pi remotely via SSH. So when I play my instrument I can have an Android phone (running some SSH client) on my music stand and start, stop or pause recording by simply entering a single letter + pressing Enter on the Android virtual keyboard.
I have never tried to compose music using Ecasound, but I suppose I would use bash script. In the begining I would put some variables, for example BEAT=60/95 (for quarter note = 95bpm) and then put effect time parameters as a mathematical expression (oh , I am not at all good in bash scripting, I hope someone correct me here) … something like
$(( $BEAT*5 ))
-you get time in seconds for the 5th beat.
The name of the person very good in composing with Ecasound is Julien Claassen, here is his paper :
Back in the days of Ardour 2 a lot of us used Qtractor for MIDI sequencing and it worked great. I used to export each individual track as a wav file and then import them in Ardour2 for mixing. Qtractor is still actively developed (by only one man: Rui Nuno Capela) and available and runs smoothly on RPi. ( “sudo apt install qjackctl qtractor” )