Just Intonation (Part 4)

In Part 2 we saw there are some choices required when trying to pick a 12-note scale in just intonation:

tonic      1minor 2nd16/15major 2nd10/9 or 9/8minor 3rd6/5major 3rd5/4perfect 4th4/3tritone25/18 or 45/32 or 64/45 or 36/25perfect 5th3/2minor 6th8/5major 6th5/3minor 7th16/9 or 9/5major 7th15/8octave2

Theoretically, there are

2 × 4 × 2 = 16

choices. But one is more popular than all the rest—at least in theory. Today I wan...