I have no idea how you generate the MIDI file, but let's use the piano keyboard to describe what I'm hearing. When I play the WAV files from your progressions a

I have no idea how you generate the MIDI file, but let's use the piano keyboard to describe what I'm hearing. When I play the WAV files from your progressions and we get to, say, an Amin chord, the Amin sounds like it is lower in pitch than the the Cmaj chord. This is OK, but it means that the 6 chord sounds an octave lower than I'm expecting it to. My ears aren't trained enough to know if what I'm hearing is an inversion where you're playing the A note in Amin from the same octave as Cmaj but you're also playing the C and E notes from the same octave, or the A note itself is lower in pitch than the C. I would have expected to hear an Amin chord where the A note was a whole step above the G in Cmaj, and the C and E both higher than the A note.