22. Non-equal temperament and adjustable guitars and pianos : Ancient Greek, Byzantine and other ethnic tetrachords. The Aristoxenos segments.

See also


http://ww1.byzantine-musics.com/

http://www.musipedia.org/

Non-equal temperament  and adjustable guitar fretboard
https://www.youtube.com/watch?v=MYK_PF9WTRE
Non-equal temperament  and adjustable piano tuning
https://www.youtube.com/watch?v=X7ti6HUX5xQ

(The post has not been written yet completely)