Music Theory Basics

Study Notes

Two minor thirds are diminished, two major thirds are augmented. A minor third and a major third are either major or minor.
Avoid doubling the leading note at the start of a bar. Don't double a major third with a minor third (octaves are acceptable). You must not omit the third as it determines chord quality.
Pedal notes are lower notes that remain while upper notes change. Types of motion include contrary (opposite directions), similar (same direction, same interval), and oblique (one note stationary).
Parallel motion occurs when notes move in the same direction with the same interval. Parallel thirds and sixths are acceptable.
The seventh of a note resolves down by step (to the note below). The leading note resolves to the tonic.
Augmented sixths involve building an octave, then lowering the higher octave by a semitone.
Major thirds on augmented sixths create Italian sixths.
Major triad on augmented sixths form German sixths.
Minor thirds on augmented sixths create French sixths.

Pivot chords are used for smooth key changes during modulation. These chords relate to both the original and new key. (e.g., (Q2/5)).
Diatonic notes are within a scale, chromatic notes are outside.
Major keys can be established by moving 1 semitone down from the last sharp and using primary chords.
Secondary dominants and other chord extensions (7ths, 9ths, 11ths, 13ths) strengthen progressions.
Melodic decoration uses non-chord tones (e.g., passing, anticipation, appoggiatura).

7th chords, like triads, can be inverted by moving the lowest note.
Vertical intervals are the distances between concurrent notes (measuring size like 2nds, 3rds etc, in combination with quality such as major, minor) and are used to create harmony.