Install jack-keyboard by entering the following commands in the terminal:
sudo apt update sudo apt install jack-keyboard
Description:
Virtual MIDI keyboard for JACK MIDI
JACK keyboard is a program that allows you to send JACK MIDI events (play ;-) using your PC keyboard. It's somewhat similar to vkeybd, except it uses JACK MIDI instead of ALSA, and the default keyboard mapping is much better - it uses the same layout as trackers (like Impulse Tracker) did, so you have two and half octaves under your fingers.
Homepage: http://jack-keyboard.sourceforge.net
Version: 2.7.1-1build2
Section: universe/sound