Hello DavidT,

DavidJ's explanation is correct. To elaborate, the .not files that play through your speakers rather than you keyboard were probably last saved by you, or someone else, who had assigned the tracks to the soundcard device.

Try this: Open such a .not file. Reassign the tracks to your MIDI keyboard device, which you already know how to do. Save the .not file. Then reopen the .not file. You will then find that it will remember the assignment of the tracks to your MIDI keyboard device.

Cheers
-- Mark