midi tracks off by a semitone
I have GarageBand 10.3.1.
When I started my project, I set the key at the top to e flat major (the key of the song). I recorded vocal, guitar tracks separately though a microphone. I added an electric piano through an instrument cable (i.e. non-midi). I then added a bunch of midi tracks with an external midi keyboard. I realized after listening they sounded bad and realized the notes were one semitone flat. If I change the song's key up to E major the midi now is correct but the guitar and vocals have now been moved up a semitone. Strangely, the non-midi piano sounds fine...it didn't change anything...I would have thought it would move that up a semitone like the vocals and guitar.
How do I set all the midi tracks to have the correct notes while leaving the other tracks unaffected?
MacBook Pro 15″, macOS 10.15