Pitch perception tracks periodicity.
Doubling frequency corresponds approximately to an octave relation.
Side 109
Music Theory
A study of how musical events relate across time. This Side uses a mainly tonal analytical toolkit while keeping the boundary visible: music theory contains many traditions, and no single system explains all music.
sound→relation→pattern→expectation→form
06study lenses
36working concepts
V0working model
109Side
Pitch relationships create one layer of musical structure.
Intervals, scales and tonal centers organize expectations in many—not all—musical traditions.
Measure distance between pitches.
Intervals can be described by semitones, scale degrees or tuning ratios.
Choose a recurring pitch collection.
Scales provide a local vocabulary, not a complete theory of melody or harmony.
A tonal center organizes stability.
Notes and chords acquire different functions relative to the center.
Some combinations sound relatively stable.
Perceived stability depends on acoustics, voicing, context and learned style.
Pitch grids are design choices.
Equal temperament solves modulation problems by distributing tuning error.
Rhythm organizes duration and onset.
Meter adds a recurring hierarchy of strong and weak positions, while groove emerges from pattern and timing.
A perceived regular beat.
The pulse can be explicit in sound or inferred from recurring events.
Group pulses hierarchically.
Duple, triple and compound meters create different expectation structures.
Divide beats into smaller units.
Subdivision provides the grid against which syncopation and timing deviations are heard.
Accent weak positions or displace expected attacks.
Syncopation creates tension by contradicting metric expectation.
Layer incompatible subdivisions.
Multiple rhythmic grids can coexist without sharing every accent.
Rate changes perception of pattern.
The same rhythm can feel structurally different at another speed.
Harmony studies simultaneous and successive pitch combinations.
In tonal music, chords gain function from how they create and release expectation.
Stack scale tones into a chord.
Major and minor triads provide compact harmonic identities.
Chords behave relative to a tonal center.
Tonic, predominant and dominant functions describe directional roles rather than mere labels.
A harmonic-melodic closure pattern.
Cadences signal varying degrees of arrival.
Instability can drive motion.
Treatment of dissonance is style-dependent and historically variable.
Shift the tonal center.
Pivot chords, direct shifts and chromatic reinterpretation change the harmonic frame.
Use pitches outside the prevailing collection.
Chromatic tones can color, intensify or destabilize tonal function.
Voice leading tracks how individual lines move through harmony.
Smooth local motion can explain why two chord progressions with identical labels feel different.
Keep shared notes in place.
Retention reduces motion and strengthens continuity.
Move voices by small intervals.
Small changes often sound connected and singable.
Voices move in opposite directions.
Contrary motion preserves independence and can strengthen cadential effect.
Repeat a chord tone in another voice.
Doubling changes balance and can create or avoid specific parallels.
Unstable tones move toward expected targets.
Expectation depends on style, register and harmonic context.
Each part should make sense horizontally.
Chord-to-chord correctness does not guarantee coherent individual voices.
Form is the large-scale organization of musical time.
Repetition, contrast and return help listeners group events into larger units.
A small recognizable idea.
Motives can be repeated, varied, fragmented or combined.
A perceptual musical sentence.
Phrases often organize around beginnings, continuation and closure.
Pair related phrases.
Antecedent and consequent relations create question-and-answer structure.
Two major sections.
Return, contrast and tonal plan determine whether sections feel balanced or directional.
A–B–A organization.
Return gains meaning because the contrasting middle changes memory of the opening.
Transform prior material.
Expansion, fragmentation and recombination create continuity without literal repetition.
Analysis is a way to hear relations, not a verdict on musical value.
Choose the analytical lens that fits the repertoire and the question.
Remove surface detail to expose deeper motion.
Useful reductions reveal hierarchy but can erase timbre and rhythm if overused.
Compare pitch collections.
Pitch-class approaches are useful where tonal function is weak or absent.
Track meter, grouping and timing.
Harmony alone cannot explain groove or temporal tension.
Mark sections and returns.
Large-scale labels should follow audible evidence rather than textbook expectation.
Sound color can carry structure.
Production, instrumentation and register may function like harmony in some music.
Theory is historically situated.
Analytical systems should not be mistaken for universal laws of musical cognition.