The frets are spaced on the fretboard so as to divide the strings into small whole number ratios. The six strings can each be tuned to vibrate at any frequency. Using precise whole number ratios improves the clarity of the sound of the intervals, which are out of tune in a typical guitar. This guitar is tuned to various frequencies, particularly 444 Hz and 528 Hz for their mathematical and aesthetic qualities.
Fretboard Ratios
16:15 9:8 7:6 6:5 5:4 4:3 7:5 3:2 8:5 5:3 7:4 9:5 15:8 2:1
This was recorded many years ago. This is the version that aired on WXNZ-LP in Skowhegan a while back. Harmonic evolution refers to Richard Merrick’s paper on Harmonically Guided Evolution. In his harmonic interference theory, the human heart is structurally and functionally organized around the musical major sixth interval (5:3) and the golden ratio. The pure 5:3 ratio here is far more pleasant sounding than the equal tempered interval.
This piece is actually called Life at the Pond. At the 1:50 mark, you can hear the pure 7/4 ratio for quite a while, a lovely interval you need to bend the strings to reach on a typical guitar.
This video was also recorded quite a while ago. It’s a somewhat rambling demonstration and description of how to play the guitar more precisely in tune. There is one universal harmonic pattern. Perhaps it would be a good idea to play in tune with it.