Aq chord on guitar
A quartal
Try its neighbors — hover to hear them
Notes
Understanding the Aq chord
How it's built: Unlike traditional chords built by stacking thirds, the quartal chord is built by stacking perfect fourths (for example: root, fourth, and minor seventh). This structure breaks with centuries of classical harmony.
How it sounds: It sounds ambiguous, highly sophisticated, and very modern. Lacking the classic tonal scaffolding, it sounds neither major nor minor. It is pure harmonic architecture, featuring a cool yet immensely rich profile.
Where to use it: It is the definitive sound of modal jazz (popularized by pianists like McCoy Tyner) and is essential in contemporary soundtracks or progressive music. It is often used over modal vamps (such as Dorian or Mixolydian improvisations) where a traditional chord would limit the melody's options. On the piano, playing quartal voicings with the left hand is a direct shortcut to a professional modern jazz sound.