When I input and play back a bunch of C chords in the BIAB chord sheet they don't sound like C chords on my piano keyboard.

Instead I have to play lower A chords on my MIDI keyboard to sound like what's playing back from BIAB

In other words the sounds out of BIAB are higher than what the chord sheet shows. I have to write in Eb chords in BIAB
to sound like C chords on my keyboard.

How do I fix this ? I don't think my piano keyboard is tunable.

Any help would be appreciated.

Bob