Music Theory Fundamentals

Music theory is the grammar of music — it explains why certain combinations of notes sound good together and gives you a vocabulary to describe what you hear. The three core concepts are intervals, scales, and keys.

An interval is the distance between two notes, measured in semitones (half steps). Common intervals: minor second (1 semitone), major second (2), minor third (3), major third (4), perfect fifth (7), octave (12). Every chord and scale is built from intervals. Learning to recognize intervals by ear is one of the most valuable skills a musician can develop.

A scale is an ordered set of notes within an octave. The major scale (7 notes, pattern: whole-whole-half-whole-whole-whole-half) is the reference point for Western music. A key is the scale that a piece of music is built around. When you know the key, you know which chords and notes will sound natural together. The key of C major uses only white keys on the piano: C, D, E, F, G, A, B.