7L 3s (4/1-equivalent)
7L 3s<4/1> (sometimes called diaquadic) refers to a non-octave MOS scale family with a period of a 4/1 and which has 7 large and 3 small steps. These scales are in some ways a double octave clone of diatonic scales because they are generated from perfect fifths and have the 7edo/7ed4 685-cent flat fifth and 5edo/10ed4's 720-cent sharp fifth at the ends of the tuning spectrum. However, ~3/2 is now the chroma-negative rather than chroma-positive generator, equalized and collapsed tunings are now swapped (equalized is 720-cent fifth and collapsed is 685-cent fifth), and the basic tuning is now the 705-cent gentle fifth from 17edo/17ed4 instead of 12edo's fifth. Diaquadic scales are also more widely spaced than diatonic scales, closer melodically to an octave-period pentatonic scale.
| ↖ 6L 2s⟨4/1⟩ | ↑ 7L 2s⟨4/1⟩ | 8L 2s⟨4/1⟩ ↗ |
| ← 6L 3s⟨4/1⟩ | 7L 3s (4/1-equivalent) | 8L 3s⟨4/1⟩ → |
| ↙ 6L 4s⟨4/1⟩ | ↓ 7L 4s⟨4/1⟩ | 8L 4s⟨4/1⟩ ↘ |
sLLsLLsLLL
Intervals
| Dark generators | Notation (J = 1/1) | Bright generators | Notation (J = 1/1) | ||
|---|---|---|---|---|---|
| 0 | J | perfect 0-step | 0 | J | perfect 10-step |
| 1 | M | perfect 3-step | 1 | Q | perfect 7-step |
| 2 | Pb | minor 6-step | 2 | N | major 4-step |
| 3 | Sb | minor 9-step | 3 | K | major 1-step |
| 4 | Lb | minor 2-step | 4 | R | major 8-step |
| 5 | Ob | minor 5-step | 5 | O | major 5-step |
| 6 | Rb | minor 8-step | 6 | L | major 2-step |
| 7 | Kb | minor 1-step | 7 | S | major 9-step |
| 8 | Nb | minor 4-step | 8 | P | major 6-step |
Modes
- LLLsLLsLLs 9|0
- LLsLLLsLLs 8|1
- LLsLLsLLLs 7|2
- LLsLLsLLsL 6|3
- LsLLLsLLsL 5|4
- LsLLsLLLsL 4|5
- LsLLsLLsLL 3|6
- sLLLsLLsLL 2|7
- sLLsLLLsLL 1|8
- sLLsLLsLLL 0|9
Scale tree
| Dark generator | Cents | L | s | L/s | Comments |
|---|---|---|---|---|---|
| 3\10ed4 | 720.000 | 1 | 1 | 1.000 | |
| 14\47ed4 | 714.894 | 5 | 4 | 1.250 | |
| 11\37ed4 | 713.514 | 4 | 3 | 1.333 | |
| 8\27ed4 | 711.111 | 3 | 2 | 1.500 | |
| 13\44ed4 | 709.091 | 5 | 3 | 1.667 | Quarchy is around here |
| 5\17ed4 | 705.882 | 2 | 1 | 2.000 | Basic diaquadic |
| 12\41ed4 | 702.439 | 5 | 2 | 2.500 | |
| 7\24ed4 | 700.000 | 3 | 1 | 3.000 | Tetrominant is around here |
| 9\31ed4 | 696.774 | 4 | 1 | 4.000 | Meanquad is around here |
| 11\38ed4 | 694.737 | 5 | 1 | 5.000 | |
| 2\7ed4 | 685.714 | 1 | 0 | -> ∞ |
Temperaments
There are two major rank-2 temperament interpretations of diaquadic, corresponding to double octave clones of meantone and archy.
Meanquad
Main article: Meanquad
- Subgroup: 4.5.6
- Comma list: 81/80
- Supporting ETs: 7, 31, 38, 24, 17, 10, 69, 45, 55, 11[-5], 52, 41, 13[+5], 27[+5]
- CTE tuning: ~3/2 = 697.214
Tetrominant
- Subgroup: 4.5.6.7
- Comma list: 36/35, 64/63
- Supporting ETs: 7, 17, 24, 10, 31, 41, 27[+5], 38[+7], 55[+7], 58[+5, +7], 65[+5, +7], 44[+5], 75[+5, +7]
- CTE tuning: ~3/2 = 699.622
Quarchy
- Subgroup: 4.6.7
- Comma list: 64/63
- Supporting ETs: 10, 17, 7, 27, 37, 44, 13, 24, 47, 11[+7], 23, 57, 16, 41
- CTE tuning: ~3/2 = 709.595