85/64

85/64, the septendecimal fourth, is a 17-limit interval that closely approximates 4/3, from which it differs by 256/255. Because it differs from 15/8 by 24/17, this interval is an easy, relatively low-prime substitute for 4/3 in scales where one desires to simultaneously maintain Rothenberg propriety and ensure that all notes in the scale suggest the Tonic as the virtual fundamental when played simultaneously.

Interval information

Ratio	85/64
Factorization	2-6 × 5 × 17
Monzo	[-6 0 1 0 0 0 1⟩
Size in cents	491.2691¢
Name	septendecimal fourth
FJS name	[math]\displaystyle{ \text{P4}^{5,17} }[/math]
Special properties	reduced, reduced harmonic
Tenney norm (log2 nd)	12.4094
Weil norm (log2 max(n, d))	12.8188
Wilson norm (sopfr(nd))	34
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See also

• 128/85 – its octave complement
• 96/85 – its fifth complement
• Gallery of just intervals