6 5 Rule
1 min read
0 views
In many musical tuning systems the ratio 6 : 5 is a key building block.
The 6th harmonic of a fundamental frequency is six times that frequency, the 5th harmonic is five times it, and the ratio of these two overtones is therefore 6 : 5. In just‑intonation the interval that corresponds to a frequency ratio of 6 : 5 is the minor third; it is about 316 cents long (compared with the 400 cents of the Pythagorean minor third and 300 cents of the equal‑temperament minor third).
Because the 6 : 5 overtone relationship occurs naturally in the harmonic series, it is often referred to in discussions of tuning as the “6‑5 rule.” Tuners and composers use it to decide where to place the third scale degree in a just‑intonated scale, to achieve a consonant minor third that matches the physics of vibrating strings or air columns.
No comments yet. Be the first to comment!