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, and does not have compounding accidentals for large EDOs, although it will feature complex rational numbers as the amount of sharps. Excluding the no-fifth systems of 1edo-4edo and 8edo, there are 4 EDOs (all multiples of 7edo) that cannot be notated using the native fifth: . However, it is still possible to notate them as subsets of 42edo (for 14edo and 21edo), 56edo (for 28edo), and 70edo (for 35edo). 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 3rd", meaning a minor 3rd 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".
Examples
Degree | Cents | Notation | ||
---|---|---|---|---|
0 | 0.000 | perfect unison | P1 | D |
1 | 70.588 | minor 2nd | m2 | Eb |
2 | 141.176 | neutral 2nd | n2 | Eb1/2 |
3 | 211.765 | major 2nd | M2 | E |
4 | 282.353 | minor 3rd | m3 | F |
5 | 352.941 | neutral 3rd | n3 | F#1/2 |
6 | 423.529 | major 3rd | M3 | F# |
7 | 494.118 | perfect 4th | P4 | G |
8 | 564.706 | 1/2-aug 4th, dim 5th | 1/2-A4, d5 | G#1/2, Ab |
9 | 635.294 | aug 4th, 1/2-dim 5th | A4, 1/2-d5 | G#, Ab1/2 |
10 | 705.882 | perfect 5th | P5 | A |
11 | 776.471 | minor 6th | m6 | Bb |
12 | 847.059 | neutral 6th | n6 | Bb1/2 |
13 | 917.647 | major 6th | M6 | B |
14 | 988.235 | minor 7th | m7 | C |
15 | 1058.824 | neutral 7th | n7 | C#1/2 |
16 | 1129.412 | major 7th | M7 | C# |
17 | 1200.00 | perfect octave | P8 | D |
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-dim major 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 |