MidiKeys

Sometime it's wonderful to not need to connect in a keyboard to play about with a softsynth, particularly when you're writing one. So here's a little app you can make use of rather. It reveals a little keyboard on screen, and also you can utilize the computer system keyboard to play MIDI notes. 'z' with ',' is the octave starting a middle C (note 60). The tricks on the row over are flats (black secrets), and also the octave below gets on the row starting with 'q' (as well as the digit row is that octave's apartments).

On top of that, you can choose a MIDI resource and see incoming notes played on the keyboard.