21/13: Difference between revisions

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'''21/13''', the '''tridecimal supraminor sixth''', is ''ca''. 830 [[cent]]s in size. It has a very good approximation in [[13edo]].
'''21/13''', the '''tridecimal supraminor sixth''', is ''ca''. 830 [[cent]]s in size. It has a very good approximation in [[13edo]].


This interval is a ratio of two consecutive Fibonacci numbers, therefore it approximates the [[golden ratio]]. In this case, 21/13 is ~2.8 [[cent|¢]] flat of the golden ratio.
This interval is a ratio of two consecutive Fibonacci numbers, therefore it approximates the [[golden ratio]], specifically [[acoustic phi]]. In this case, 21/13 is ~2.8 [[cent|¢]] flat of the golden ratio.


== See also ==
== See also ==

Revision as of 15:46, 21 October 2022

Interval information
Ratio 21/13
Factorization 3 × 7 × 13-1
Monzo [0 1 0 1 0 -1
Size in cents 830.2532¢
Name tridecimal supraminor sixth
Color name thuzo 6th, 3uz6
FJS name [math]\displaystyle{ \text{M6}^{7}_{13} }[/math]
Special properties reduced
Tenney height (log2 nd) 8.09276
Weil height (log2 max(n, d)) 8.78463
Wilson height (sopfr(nd)) 23

[sound info]
Open this interval in xen-calc

21/13, the tridecimal supraminor sixth, is ca. 830 cents in size. It has a very good approximation in 13edo.

This interval is a ratio of two consecutive Fibonacci numbers, therefore it approximates the golden ratio, specifically acoustic phi. In this case, 21/13 is ~2.8 ¢ flat of the golden ratio.

See also