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]], and notably, 5 of these intervals differ from [[11/1]] by 4084223/4084101, a comma of a mere 0.052{{cent}}. | ||
This interval is a ratio of two consecutive Fibonacci numbers | This interval is a ratio of two consecutive {{w|Fibonacci numbers}} and thus a convergent to [[acoustic phi]] (the interval of a [[golden ratio]]). In this case, 21/13 is ~2.8{{cent}} flat of acoustic phi. It differs from [[13/8]], the previous such convergent, by [[169/168]], and from the following convergent [[34/21]] by [[442/441]]. | ||
== See also == | == See also == | ||