Non-Western Cultures

The endpoints of the syntonic tuning continuum are 7-tone equal temperament (7-tet, P5=686 cents) and 5-tone equal temperament (5-tet, P5=720 cents).

This is particularly interesting because some non-Western cultures use these tunings (or tunings very similar to these). For example,
- The traditional Indonesian slendro scale is similar to 5-tet.
- The traditional scale of the Thai renat is similar to 7-tet.
- The traditional scale of the Mandinka African balafon is similar to 7-tet.

It has been suggested that these cultures' instruments emit sound spectra which (in isolation or when crossed with a harmonic timbre such as a human voice) are maximally consonant when played in these tunings.

This is not to say that these cultures necessarily use other musical structures from the syntonic temperament -- scales, chords, etc. But...who knows?

If the human mind categorizes tonal relationships in a tuning invariant manner, then perhaps tuning invariance can provide the foundation for a unified theory of music that generalizes music theory beyond the Harmonic Series to embrace a wide range of pseudo-harmonic tunings/spectra, from 7-tet to 5-tet and everything in between, including the ubiquitous Western 12-tet.