33/25
| Interval information |
5edo-esque fourth
[sound info]
33/25, the ptolemismic fourth or the 5edo-esque fourth, is an 11-limit interval. It is flat of 4/3, the perfect fourth, by 100/99, the ptolemisma, hence the name. It is also sharp of 21/16, the subfourth, by 176/175, the valinorsma. Being 11/8 diminished by 25/24, it is technically a semidiminished fourth aka paraminor fourth.
Approximation
Measuring about 480.6 ¢, 33/25 is very well approximated by 5edo and its supersets.
| Edo | Step size | Cents (¢) | Absolute error (¢) | Relative error (%) |
|---|---|---|---|---|
| 5 | 2\5 | 480.00 | -0.65 | -0.27 |
| 10 | 4\10 | 480.00 | -0.65 | -0.54 |
| 15 | 6\15 | 480.00 | -0.65 | -0.81 |
| 20 | 8\20 | 480.00 | -0.65 | -1.08 |
| 25 | 10\25 | 480.00 | -0.65 | -1.34 |
| 30 | 12\30 | 480.00 | -0.65 | -1.61 |
| 35 | 14\35 | 480.00 | -0.65 | -1.88 |
| 40 | 16\40 | 480.00 | -0.65 | -2.15 |
| 45 | 18\45 | 480.00 | -0.65 | -2.42 |
| 50 | 20\50 | 480.00 | -0.65 | -2.69 |
| 55 | 22\55 | 480.00 | -0.65 | -2.96 |
| 60 | 24\60 | 480.00 | -0.65 | -3.23 |
| 65 | 26\65 | 480.00 | -0.65 | -3.50 |
| 70 | 28\70 | 480.00 | -0.65 | -3.77 |
| 75 | 30\75 | 480.00 | -0.65 | -4.03 |
| 80 | 32\80 | 480.00 | -0.65 | -4.30 |
See also
- 50/33 – its octave complement
- 25/22 – its fifth complement
- Gallery of just intervals
- File:Ji-33-25-csound-foscil-220hz.mp3 – another sound example