Fractional sharp notation
VERY WIP (I'll move it to the main namespace if it's finished.)
The fractional sharp notation (FSN) is a notation developed by CompactStar that is largely an extension of circle-of-fifths notation, which can be used for EDOs, and secondarily for temperaments and just intonation subgroups of rank 3. It represents all intervals with conventional accidentals, but with sharps and flats extended to have an arbitrary rational amount, denoted by a superscript or caret (like #1/2 for half-sharp) except for in the case of single and double accidentals. This means that there is support for not only half-sharps and half-flats, but third-sharps, third-flats and so on, supporting almost all EDO systems. Multiples of 7edo up to 35edo, and excluding 7edo itself, are not supported, but these are possible to be notated as subsets of larger EDOs. In particular, 14edo and 21edo can be notated as subsets of 42edo, 28edo as a subset of 56edo, and 35edo as a subset of 70edo or using the alternative fifth from 5edo. 1edo to 4edo are obviously notated as subsets, and 8edo is also required to be notated as a subset of 16edo, 24edo, or 32edo with no fifth except for 750 cents. Antidiatonic fifths may be notated using both the "major wider than minor" and "minor wider than major" systems, depending on what is needed.
The sharp and flat accidentals are always taken to raise and lower by an augmented union or apotome. In a given EDO system, the step size is 1 over the sharpness of a sharp. In interval naming, x-augmented and x-diminished raise and lower by x times a chromatic semitone. These are used in the same way as augmented and diminished normally are, but additionally, "augmented minor" and "diminished major" are used for constructions like "1/3-augmented minor", meaning a minor third raised by 1/3 of an apotome (formerly these were described as a "fraction of major" like 1/3-major, the updated version was suggested by Frostburn). Since 1/2-augmented minor and 1/2-diminished major mean the same thing, they are replaced with the more conventional term "neutral".
Here is an example for 22edo:
Degree | Cents | Notation | ||
---|---|---|---|---|
0 | 0.000 | perfect unison | P1 | D |
1 | 54.545 | minor 2nd | m2 | Eb |
2 | 109.091 | 1/3-aug minor 2nd | 1/3-AM2 | Eb2/3 |
3 | 163.636 | 1/3-dim major 2nd | 1/3-dM2 | Eb1/3 |
4 | 218.182 | major 2nd | M2 | E |
5 | 272.727 | minor 3rd | m3 | F |
6 | 327.273 | 1/3-aug minor 3rd | 1/3-Am3 | F#1/3 |
7 | 381.818 | 1/3-aug dim 3rd | 1/3-dM3 | F#2/3 |
8 | 436.364 | major 3rd | M3 | F# |
9 | 490.909 | perfect fourth | P4 | G |
10 | 545.455 | 1/3-aug 4th, dim 5th | 1/3-A4, d5 | G#1/3, Ab |
11 | 600.000 | 2/3-aug 4th, 2/3-dim 5th | 2/3-A4, 2/3-d5 | G#2/3, Ab2/3 |
12 | 654.545 | aug 4th, 1/3-dim 5th | A4, 1/3-d5 | G#, Ab1/3 |
13 | 709.091 | perfect 5th | P5 | A |
14 | 763.636 | minor 6th | m6 | Bb |
15 | 818.182 | 1/3-aug minor 6th | 1/3-Am6 | Bb2/3 |
16 | 872.727 | 1/3-dim major 6th | 1/3-dM6 | Bb1/3 |
17 | 927.273 | major 6th | M6 | B |
18 | 981.818 | minor 7th | m7 | C |
19 | 1036.364 | 1/3-aug minor 7th | 1/3-Am7 | C#1/3 |
20 | 1090.909 | 1/3-dim major 7th | 1/3-dM7 | C#2/3 |
21 | 1145.455 | major 7th | M7 | C# |
22 | 1200.000 | perfect octave | P8 | D |
Just intonation
This segment will probably removed or changed
Accidentals
Prime limit | Comma | Sharps |
---|---|---|
5 | 81/80 | 1/5 |
7 | 64/63 | 1/4 |
11 | 33/32 | 1/2 |
13 | 1053/1024 | 1/2 |
17 | 4131/4096 | 1/8 |
19 | 513/512 | 1/34 |
23 | 736/729 | 1/7 |