That's great. Very hip. The harmonica nerds among us will wonder how you handled that repeated half-step modulation on the front end. My ears aren't good enough to know. Do tell!
Normal people will just listen and feel it, soaking it all in. And that's an even better way of appreciating it. A world waking up.
Thanks for asking about the harp(s) I used on that.
True, I didn't create this tune for reasons of nerdiness; the means I used were just the tools that created the set of potentials that made this particular tune possible.
The answer to your question, though, is kind of complicated and nerdy:
The background harps you hear are chromatics. But the foreground one playing the main melody and chords is a pair of diatonics in a Brendan Power Switch-Harp assembly that lets you yoke two harps together and switch back and forth between them with a slider assembly similar to that of a chromatic harmonica.
But that's not the complicated part.
The two harps are in a Magic Harp tuning that plays a pentatonic scale, with the result that the chords are voiced mostly in fourths. I call this pentaquartal tuning, penta for the five-note scale, and quartal for the quartal chords (i.e., consisting of intervals of a fourth).
For instance, a C pentaquartal harp migh start on E as blow 1 and then go:
E A D G C (which is the C major pentatonic voiced all in fourths, and then repeat E A D G C again. At the point where th pattern repeats, you do get C to E (a third) and you also get G-C-E (a C major chord) as well as C-E-A (an A minor chord). But everything else is this stack of fourths. (The draw notes are the same note sequence, but starting on G as Draw 1.)
The two harps in the Switch-Harp I used for this are in D and Bb pentaquartal tuning, with both having the starting note of D below Middle C in Hole 1 Blow. That D (the only note in common between the two scales) gives the common top note in the alternating D and Eb chords in the intro and outtro.
The chord progression on the main part of the tune is D - G (played mostly on the D harp), to G minor, Bb, and Eb (played on the Bb harp) back to D (back to the D harp). The intro you mention is just D and Eb chords alternating, using the D harp for D and the Bb harp for Eb. The interlude, mostly guitar with chromatic in the background, is Bmi7 - G - Eb - Ab - Asus. I could have handled that with the pentaquartal combo but chose to give that to guitar for a breather from out-front harmonica.
