DIN Is Noise is a musical instrument application for Mac. . When MIDI input is available, DIN draws 13 dotted crosses in the middle of the keyboard-keyboard. Each cross represents one note of the chromatic scale. You can see an octave's worth of crosses. If you play a white note on your MIDI keyboard, a white box will appear. If you play a black note, a black box will appear. In both cases, you should hear the note.