Tritone Substitutions
Tritone substitutions in jazz harmony prompt a broad exploration of how different musical traditions think about chords, dissonance, and voice leading. Commenters contrast jazz’s chord-based, functional view with Baroque and classical approaches rooted in counterpoint and historical techniques like partimento and figured bass, arguing that applying modern jazz labels to older music can be misleading. The thread also touches on just intonation vs equal temperament, how and when theory is useful for performers and improvisers, and why music theory often feels very different from learning a programming language.
Overall reaction to the article
- Many readers enjoyed seeing music theory on HN and liked the geometric/intuitive framing of tritone substitutions.
- Some found one diagram (rotation / circle) visually confusing, especially due to color choices and unclear relation to circle-of-fifths vs chromatic circle.
- A few felt the explanation of “rotate 180°” could be clearer about what, exactly, is being rotated.
Tritone substitutions: function and history
- Discussion of jazz usage: ii–V–I becoming ii–♭II–I, with the tritone sub giving a chromatic bass line and rich dominant color.
- Emphasis that in jazz comping, 3rd and 7th (“guide tones”) define function; bass choice often determines whether a tritone sub is actually heard.
- Some argue early “tritone-like” moves in Baroque/Classical works (e.g., Scarlatti) are not true tritone substitutions, but contrapuntal/voice-leading phenomena that only resemble modern jazz harmony.
- Debate over whether it is valid to apply jazz harmonic concepts retroactively to older music; consensus: fine as a personal tool, but historically questionable for scholarly analysis.
Consonance, dissonance, and tuning
- Disagreement over how “very dissonant” a tritone is.
- One camp: tritone is highly dissonant in simple-ratio / just-intonation terms.
- Another: minor seconds are more dissonant; tritone is only “moderately” tense and culturally framed.
- Several argue consonance/dissonance is contextual and learned, not absolute; blues, other cultures, and equal temperament shift perceptions.
- Some microtonal / just-intonation comments note multiple distinct tritones (7/5 vs 10/7) and intonation tradeoffs in tritone subs.
Notation and enharmonics
- Strong push to spell tritone-sub chords correctly (e.g., D♭7 rather than C#7 for a G7 sub), maintaining stacked thirds and functionally sensible Roman numerals (e.g., ♭II7 vs V7/♯IV).
- Discussion of when to choose sharps vs flats: direction of motion, key signature, chord spelling, and instrument ergonomics (e.g., harp, accordion).
Music theory vs counterpoint, history, and culture
- Repeated reminder that much pre-19th-century music was conceived in terms of counterpoint, intervals, partimento, and melodic reduction, not chord labels.
- Several recommend counterpoint and partimento resources and mention Schenkerian analysis, noting both its analytical influence and its problematic ideological baggage.
- Some criticize treating “functional harmony” as universal; stress that theory is descriptive, culture-specific, and often retrofitted to existing practice.
Music theory, coding, and learning
- Many coders ask how music theory “feels” to learn compared to programming.
- Common answer:
- Composition and improvisation ≈ “writing” and “speaking”;
- Theory is more like grammar and patterns than strict algorithms.
- Strong theme: the real goal is ear training and internalization so theory disappears in performance.
- Several lament that instrumental education (especially for single-line instruments) often omits harmonic understanding, making playing feel like “just work.”