There are many tunings available for the 10-Hole Diatonic, Blues
harmonica. With Ricther Tuning being the overwhelming tuning in use. The major harmonic manufactures of various tunings and my favorite harmonica company, Seydel offers many tunings: Natural Minor, Harmonic Minor, Paddy Ricther, Country Tunings, Melodic Maker, Major Cross, and more...
Ricther Tuning
Richter tuning is the most common tuning type seen on diatonic harmonicas. Named after the 19th century harmonica maker, Joseph Richter , who developed the tuning.…
It provides the Tonic or I chord of Major keys on the Draw notes and the Dominant or V chord of the Major scale on the Blow notes. With full diatonic major scale on holes 4 5 6 7.
Country Tuning
This s a variation on the Ricther Tuning above
This scale is the C Lydian scale or any of the other modes in the G Major/Ionian scale/mode.
Wilde Tuning
Developed by Will Wilde for Special tuning for Rock and Blues Rock.
I designed the Wilde tuning specifically for playing hard rock and blues-rock on the harmonica. As much as I love the standard Richter tuning, I have always found it frustrating when it comes to playing “rock guitar” style licks, particularly in the upper octave. The Wilde tuning addresses all of the problems I had with Richter, whilst still retaining the bluesy feel of classic second position harmonica that we all know and love. — Will Wilde
Paddy Richter Tuning
Developed by Brendon Power for Irish melodies to played easily on the diatonic harmonica.
Piano Keyboard Reference
Major Cross Tuning
Developed by Tony Eyers for Irish melodies and traditional fiddle tunes to played easily on the diatonic harmonica.
Equal Temperament vs. Just Intonation – War of the Musical Worlds!
Check out Richard Sleigh's • War of the Musical Worlds! (Equal Temperament vs. Just Intonation) about these two tunings. This is the best explanation I've read on the difference and why you might want one vs. the other.