9/5
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Ratio
9/5
Factorization
32 × 5-1
Monzo
[0 2 -1⟩
Size in cents
1017.596¢
Names
just minor seventh,
classic(al) minor seventh,
ptolemaic minor seventh
Color name
g7, gu 7th
FJS name
[math]\text{m7}_{5}[/math]
Special properties
reduced
Tenney height (log2 nd)
5.49185
Weil height (log2 max(n, d))
6.33985
Wilson height (sopfr(nd))
11
Harmonic entropy
(Shannon, [math]\sqrt{nd}[/math])
~4.16356 bits
[sound info]
open this interval in xen-calc
| Interval information |
classic(al) minor seventh,
ptolemaic minor seventh
(Shannon, [math]\sqrt{nd}[/math])
[sound info]
English Wikipedia has an article on:
9/5, the just, classic(al), or ptolemaic minor seventh[1] is often treated as a consonance in 5-limit just intonation, forming a part of such chords such as the 1-6/5-3/2-9/5 minor seventh chord, and the supermajor tetrad, 1-9/7-3/2-9/5 in the 7-limit.
Coincidentally, the ratio between a common "alternative" tuning frequency (A432) and the most common AC electrical frequency (60hz) is exactly 36/5, two octaves above 9/5. This is notably a more consonant interval than the 11/6 formed by the more common tuning frequency of A440, which may lead to a noticeable improvement in consonance when electrically powered instruments or amplifiers are interfered with by AC power.