Each musical key's emotional color is shaped by how fast its intervals beat—specifically the major third. A major third that is wide of just intonation beats faster; one that is close to just beats slowly or not at all. Fast-beating thirds feel agitated, tense, and energized. Slow-beating thirds feel calm, warm, and intimate. The central question of this project is: can a tuning system paint different emotional states in different keys?
Source: Emotion Taxonomy (deep-research-report2.md) · Cross-referenced with 24 Musical Key Profiles. Arousal badges: High Med Low
E01–E12 · Luminous states — positive and approach-oriented
E13–E24 · Shadow states — negative and avoidance-oriented
For each of ten representative tuning systems, the table below shows how many of the twelve major keys fall into each M3 beat-speed zone. A system that covers more zones can express a wider range of emotional states through key choice alone. M3 dev = how many cents the major third exceeds just intonation (386.31¢); ET = 13.69¢. Computed from api_export_temperaments_20260227.json.
| Tuning System | M3 dev range |
Zone 1 Serene < 2¢ |
Zone 2 Tender 2–8¢ |
Zone 3 Centered 8–14¢ |
Zone 4 Spirited 14–20¢ |
Zone 5 Agitated ≥ 20¢ |
Zones covered |
Emotional reach |
|---|---|---|---|---|---|---|---|---|
| E03 E23 | E17 E18 E04 E05 | E06 E08 E09 E14 | E02 E07 E11 E12 | E01 E13 E15 E16 | ||||
| Equal Temperament | 12.7–14.7¢ | — | — | 7 | 5 | — | 2/5 | Narrow |
| Viennese (Hummel) | 12.8–14.6¢ | — | — | 8 | 4 | — | 2/5 | Narrow |
| C.P.E. Bach | 12.1–16.8¢ | — | — | 7 | 5 | — | 2/5 | Narrow |
| Neidhardt Small City | 5.9–17.6¢ | — | 2 | 4 | 6 | — | 3/5 | Moderate |
| Vallotti–Young | 5.9–21.5¢ | — | 3 | 4 | 2 | 3 | 4/5 | Broad |
| Vallotti | 5.9–21.5¢ | — | 3 | 4 | 2 | 3 | 4/5 | Broad |
| Werckmeister III | 3.9–21.5¢ | — | 2 | 3 | 4 | 3 | 4/5 | Broad |
| Kirnberger III | 0–21.5¢ | 1 | 2 | 2 | 5 | 2 | 5/5 | Full spectrum |
| 1/6-comma Meantone | 7.2–26.7¢ | — | 8 | — | — | 4 | 2/5 | Narrow |
| 1/4-comma Meantone | -0–41.1¢ | 8 | — | — | — | 4 | 2/5 | Narrow |
Note on 1/4-comma Meantone: its bimodal distribution (8 serene keys + 4 agitated wolf thirds, nothing between) means it can only paint two emotional extremes—it actually covers fewer emotional zones than a good well temperament, despite having purer thirds overall.