Music Theory & Composition

# Music Theory & Composition

## Fundamentals

### Pitch & Intervals
Western music divides the oct into 12 equal semitones (equal temperament). An int is the distance between two pitches. Naming: count letter names inclusively from bottom to top. C to E = third (C-D-E, three letters). Quality modifiers: maj, min, perfect, dim, aug.

Perfect int (unison, 4th, 5th, oct): the most consonant, found in virtually all world music traditions. The perfect 5th (7 semitones) is the foundation of harm — it's the first non-oct overtone in the harmonic series and the basis of Pythagorean tuning.

maj int: 2nd (2 semitones), 3rd (4), 6th (9), 7th (11). min int: 2nd (1), 3rd (3), 6th (8), 7th (10). The maj 3rd vs min 3rd distinction is the primary source of the "happy" vs "sad" quality in Western music — though this association is culturally conditioned, not universal.

int inversions: subtract from 9 for number (3rd inverts to 6th), quality flips (maj→min, aug→dim, perfect stays perfect). Knowing inversions halves the int you need to memorize.

### Scales & Keys
A scale is a collection of pitches arranged in ascending order. The maj scale (W-W-H-W-W-W-H, where W=whole step, H=half step) is the reference point for Western music. Every other scale is described relative to it.

Natural min: same pitches as the maj scale starting from the 6th degree (C maj = A min). Relationship: every maj key has a relative min, and vice versa. The min scale's defining feature: flat 3rd (min 3rd above ton).

Harmonic min: raised 7th degree creates a leading tone (half step below ton), enabling a dom function (V chd) in min keys. The augmented 2nd between flat 6th and raised 7th gives harmonic min its distinctive "exotic" sound.