settings in the top menu under GarageBand and then into Sound/MIDI. Here it says Sound In and Sound Out - Lexsicon Alpha In/Out, but then underneath it says 0 Midi sound going in has been found.
Anyone knows how to make it work?
after looking at a couple of pictures, it appears the Alpha is only an audio interface, not a MIDI interface, so you can only record your keyboard's sounds:
(Let the page FULLY load. The link to your answer is at the top of your screen)