Harmonic Functions (T-PD-D)
The three fundamental roles chords play in tonal music—Tonic (stability and rest), Pre-dominant (preparation and setup), and Dominant (tension and forward drive)—that govern chord progression logic, create predictable resolution patterns, and form the grammatical foundation of 300+ years of Western music from Bach to contemporary pop.
Interactive Visualizations
The Functional Harmony Circle
T-PD-D-T cycle with all allowed and forbidden motions
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Function Assignment Reference
Complete chart of which chords belong to which function (major and minor)
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Tension Gradient Visualization
Harmonic tension levels from T (0) → PD (moderate) → D (maximum) → T (resolution)
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Functional Substitution Table
Primary functions and their substitutes (I↔vi, IV↔ii, V↔vii°)
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Progression Decision Tree
How to choose next chord based on current function
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Historical Function Evolution
How functional harmony developed from Baroque to Jazz
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I. Conceptual Positioning
🎯Problem Solved
Why do certain chord progressions sound 'right' while others sound 'wrong'—functional harmony reveals that chords have grammatical roles (not just sonorities), explains why V pulls to I (dominant demands resolution to tonic), shows why IV-V-I feels complete (pre-dominant sets up dominant which resolves to tonic), and provides the logical framework that makes tonal music coherent and predictable.
🔨Skills Built
- •Identify harmonic function of any chord (T, PD, or D)
- •Understand why certain progressions sound logical
- •Predict resolution patterns and cadences
- •Apply functional substitution (vi for I, ii for IV)
- •Recognize functional exceptions (deceptive cadences, retrogression)
- •Use functional logic in composition and analysis
🔗Connects To
II. Knowledge Architecture
This section will be populated with core concepts, sub-concepts, and micro-concepts in future MDX content.
IV. Charts, Maps & Tables
Visual artifacts will be embedded in MDX content as React components.
V. Logical Learning Sequence
Learning progression will be defined in MDX content.
VII. Analytical Application
Cross-genre examples (classical, jazz, pop, film) will be provided in MDX content.
IX. Cross-Topic Network
Concept bridges and overlapping zones will be detailed in MDX content.
XI. Synthesis & Meta-Understanding
Mastery meaning and transformational impact will be explored in MDX content.