9/5
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| Ratio | 9/5 |
| Factorization | 32 × 5-1 |
| Monzo | [0 2 -1⟩ |
| Size in cents | 1017.5963¢ |
| 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{n\cdot d}[/math]) |
~4.5486 bits |
[sound info] | |
| open this interval in xen-calc | |
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.