Music Theory Reference¶
Music theory constants used by YaO's generation and verification layers.
Scales¶
YaO supports 33 scale types. The 14 standard scales are defined in src/yao/constants/music.py, and 19 extended/microtonal scales (Japanese, maqam, raga, gamelan, just intonation) are defined in src/yao/constants/scales.py as cents-based ScaleDefinition objects.
Standard Scales (14)¶
| Scale | Intervals | Example (C root) |
|---|---|---|
| major | 0,2,4,5,7,9,11 | C D E F G A B |
| minor | 0,2,3,5,7,8,10 | C D Eb F G Ab Bb |
| harmonic_minor | 0,2,3,5,7,8,11 | C D Eb F G Ab B |
| melodic_minor | 0,2,3,5,7,9,11 | C D Eb F G A B |
| dorian | 0,2,3,5,7,9,10 | C D Eb F G A Bb |
| mixolydian | 0,2,4,5,7,9,10 | C D E F G A Bb |
| lydian | 0,2,4,6,7,9,11 | C D E F# G A B |
| phrygian | 0,1,3,5,7,8,10 | C Db Eb F G Ab Bb |
| locrian | 0,1,3,5,6,8,10 | C Db Eb F Gb Ab Bb |
| pentatonic_major | 0,2,4,7,9 | C D E G A |
| pentatonic_minor | 0,3,5,7,10 | C Eb F G Bb |
| blues | 0,3,5,6,7,10 | C Eb F F# G Bb |
| whole_tone | 0,2,4,6,8,10 | C D E F# G# A# |
| chromatic | 0,1,2,3,4,5,6,7,8,9,10,11 | All 12 notes |
Extended / Microtonal Scales (19)¶
Defined in src/yao/constants/scales.py as ScaleDefinition with cents-based tuning:
| Category | Scales |
|---|---|
| Japanese | in, yo, ritsu, minyo, hirajoshi, iwato |
| Maqam | rast, bayati, hijaz, nahawand, kurd |
| Raga | yaman, bhairav, darbari, marwa, todi |
| Gamelan | slendro, pelog |
| Just Intonation | just_intonation_major |
All extended scales include cultural_context metadata.
Chord Types¶
30 chord types defined as semitone intervals:
| Chord | Intervals | Example (C root) |
|---|---|---|
| maj | 0,4,7 | C E G |
| min | 0,3,7 | C Eb G |
| dim | 0,3,6 | C Eb Gb |
| aug | 0,4,8 | C E G# |
| sus2 | 0,2,7 | C D G |
| sus4 | 0,5,7 | C F G |
| maj7 | 0,4,7,11 | C E G B |
| min7 | 0,3,7,10 | C Eb G Bb |
| dom7 | 0,4,7,10 | C E G Bb |
| dim7 | 0,3,6,9 | C Eb Gb A |
| half_dim7 | 0,3,6,10 | C Eb Gb Bb |
| aug7 | 0,4,8,10 | C E G# Bb |
| min_maj7 | 0,3,7,11 | C Eb G B |
| 7sus4 | 0,5,7,10 | C F G Bb |
| add9 | 0,4,7,14 | C E G D' |
| dom9 | 0,4,7,10,14 | C E G Bb D' |
| min9 | 0,3,7,10,14 | C Eb G Bb D' |
| maj9 | 0,4,7,11,14 | C E G B D' |
| add11 | 0,4,7,17 | C E G F' |
| min11 | 0,3,7,10,14,17 | C Eb G Bb D' F' |
| dom11 | 0,4,7,10,14,17 | C E G Bb D' F' |
| dom13 | 0,4,7,10,14,21 | C E G Bb D' A' |
| min13 | 0,3,7,10,14,21 | C Eb G Bb D' A' |
| maj13 | 0,4,7,11,14,21 | C E G B D' A' |
| maj6 | 0,4,7,9 | C E G A |
| min6 | 0,3,7,9 | C Eb G A |
| 6_9 | 0,4,7,9,14 | C E G A D' |
| 7alt | 0,4,8,10 | C E G# Bb |
| 7b9 | 0,4,7,10,13 | C E G Bb Db' |
| 7sharp9 | 0,4,7,10,15 | C E G Bb D#' |
Chord Function Notation¶
YaO uses Roman numeral notation for chord functions:
| Degree | Major Key | Minor Key |
|---|---|---|
| 0 (I/i) | maj | min |
| 1 (II/ii) | min | dim |
| 2 (III/iii) | min | maj |
| 3 (IV/iv) | maj | min |
| 4 (V/v) | maj | min |
| 5 (VI/vi) | min | maj |
| 6 (VII/vii) | dim | maj |
Concrete pitches are realized via yao.ir.harmony.realize(). Never mix functional (Roman numeral) and concrete (C, Dm7) notation in the same context.
Dynamics¶
| Marking | MIDI Velocity |
|---|---|
| ppp | 16 |
| pp | 33 |
| p | 49 |
| mp | 64 |
| mf | 80 |
| f | 96 |
| ff | 112 |
| fff | 127 |