Binary package “jack-keyboard” in ubuntu oracular
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.