Tuning - Major Diatonic, Part 21 (3rd Position, IV7 Chord)

Let's now look at the IV7 Chord in 3rd Position (same as the I7 Chord in 2nd Position and V7 Chord in 2nd Position)

I7 Chord
- G B D F

I7 Chord Blues Scale
- G Bb C Db D F G

First Octave: 1+ 1' 1 2" 2
Sequentially this is complete, running out of range for the bottom two notes of the scale.

Second Octave: 2 3' 4+ 4' 4 5 6+
This is complete and very usable.

Third Octave: 6+ (7) 7+ 8 9 9+ (10"+)
This octave only has one of the three blue notes needed to make the blues scale. Though not a very bluesy range of the harmonica, if you play with a lighter feel the high-end is very usable.

Look familiar?