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Music Theory Fundamentals

Jul 6, 2025

Overview

This lecture provides a crash course in music theory fundamentals, including notes, scales, chords, chord progressions, melodies, and rhythm, with practical exercises throughout.

What is Music Theory?

  • Music theory is the language that helps understand, interpret, and communicate about music.
  • Knowing music theory allows musicians to create and analyze music more naturally and fluently.

Notes and Pitch

  • Sound is made of vibrations, with faster vibrations producing higher notes (pitches).
  • There are twelve notes commonly used in Western music, repeating in higher and lower ranges (octaves).
  • The distance between adjacent notes is called a semitone (half-step); two semitones make a whole tone (whole step).
  • Note names are A to G for white keys; black keys are sharps (#, higher) or flats (b, lower).

Scales and Keys

  • A key is a group of notes that sound good together, typically using seven of the twelve notes.
  • The major scale formula is: whole, whole, half, whole, whole, whole, half steps.
  • The C major scale uses all white keys; other scales follow the same step pattern starting on a different root.
  • Scale degrees number notes in the scale from 1 (root) to 7.

Chords and Triads

  • Chords are multiple notes played together, usually from the same key.
  • The basic chord (triad) uses the 1st (root), 3rd, and 5th notes of the scale.
  • Major triads are spaced four then three semitones (major = 4, 3); minor triads are three then four (minor = 3, 4).
  • Each scale degree can form its own triad, leading to major or minor chords depending on degree.

Chord Progressions and Number System

  • Chord progressions often use scale degrees as shorthand (e.g. I-V-vi-IV).
  • Major scale triads follow the pattern: major, minor, minor, major, major, minor, diminished.
  • Thinking in numbers allows transposing progressions to any key.

Inversions

  • Inversions rearrange chord notes so the root, third, or fifth is the lowest note.
  • Inversions smooth out chord transitions and change chord flavor.

Melodies

  • Melodies are single note sequences often sung or played over chords.
  • Good melodies balance notes within the chord (stable) and outside the chord (tension).
  • The major pentatonic scale (major scale minus 4th and 7th notes) often sounds good for melodies.

Rhythm and Counting

  • Music is divided into bars (measures) with typically four beats per bar.
  • Beats are subdivided into quarter, eighth, and sixteenth notes (1, 1-and, 1-e-and-a).
  • Rhythmic notation helps record and communicate musical ideas.

Key Terms & Definitions

  • Semitone/Half-step — the smallest interval between two notes.
  • Whole tone/Whole step — two semitones.
  • Octave — interval between one note and the next of the same name.
  • Scale Degree — position of a note within a scale, numbered 1-7.
  • Triad — three-note chord built from the root, third, and fifth.
  • Inversion — rearrangement of chord notes so a note other than the root is lowest.
  • Pentatonic Scale — five-note scale removing 4th and 7th degrees.
  • Bar/Measure — segment of music containing a fixed number of beats.

Action Items / Next Steps

  • Practice building major scales and naming notes by both letter and scale degree.
  • Create triads on scale degrees 1-6 in several major keys and label each as major or minor.
  • Compose chord progressions using the number system and try transposing to different keys.
  • Experiment with chord inversions for smoother progressions.
  • Write melodies over chord progressions, using the pentatonic scale if needed.
  • Analyze rhythms from songs you like using sixteenth note notation.