• Triad: root, third, fifth
  • Intervals:
    • Half-step: generally the distance between two adjacent ‘notes’ on an instrument (keys on a piano or frets on a guitar) - this is normally 20Hz
    • Major third: 4 half-steps
    • Minor third: 3 half-steps
  • Types of triads (1, 3, 5)
    • Major:
      • 1-3 is a major, 3-5 is a minor
    • Minor:
      • 1-3 is a minor, 3-5 is a major
      • Basically like a major but lower the third by a half-step
    • Augmented
      • 1-3 is a major, 3-5 is a major
      • Basically like a major but raise the fifth by a half-step
    • Diminished
      • 1-3 is a minor, 3-5 is a minor
      • Major but lower the third and fifth by a half-step
  • 7th chord:
    • Major: major triad with a major third on top
    • Minor: minor triad with minor third on top
    • Dominant: major triad with a minor third on top
    • Suspended: major triad but replace the third
      • Sus4 (default for sus): replace with the fourth
      • Sus2: replace with the second
      • Sus7: replace with the seventh
  • Extensions
    • Add 9 (can be modified with flat or sharp)
    • Add 11 (can be modified with flat or sharp)
    • Add 13 (can be modified with flat or sharp)
  • Progressions
    • I-IV-V-I (classical)
    • I-IV-V-VI (pop)
    • ii-V-I (jazz)
      • Up a 4th and down a 5th