40/27
| Ratio | 40/27 |
| Factorization | 23 × 3-3 × 5 |
| Monzo | [3 -3 1⟩ |
| Size in cents | 680.44871¢ |
| Names | wolf fifth, classic grave fifth |
| Color name | y5, yo 5th |
| FJS name | [math]\text{P5}^{5}[/math] |
| Special properties | reduced |
| Tenney height (log2 nd) | 10.0768 |
| Weil height (log2 max(n, d)) | 10.6439 |
| Wilson height (sopfr (nd)) | 20 |
| Harmonic entropy (Shannon, [math]\sqrt{n\cdot d}[/math]) |
~4.44057 bits |
[sound info] | |
| open this interval in xen-calc | |
The classic grave fifth of 40/27 is the interval between 9/8 and 5/3. It is a syntonic comma (81/80) flat of 3/2. In some contexts it may be considered a "wolf fifth". In meantone, of course, it is equated with a perfect fifth.
Although often underappreciated and even avoided on account of its dissonant sound in comparison to the perfect fifth, it can nevertheless prove useful in the hands of the right composer. Specifically, when used as an interval in its own right, or as the interval spanning the difference between the root and the fifth of a chord, its dark and active sound creates a kind of tension that, in classical-leaning or even medieval-leaning styles, can be arguably followed up either by a chord containing a 64/45 tritone for an increase in tension, or by a chord with a perfect fifth between the root and the fifth for a decrease in tension. Alternatively, a chord built around this grave fifth may be used in chord that acts as the final chord in a deceptive cadence with the effect of making such a cadence all the more powerful.