Augmented triad with added ♯9; bright, unstable color for modern dominant motion.
Intervals from the root that spell this chord and its chord tones.
Scales that contain this chord’s notes and usually fit over it.
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The augmented add ♯9 sonority combines two strong colors: the raised fifth of an augmented triad and the altered upper tension of a sharp ninth. The result is bright, unstable, and expressive, with a modern harmonic edge that can sound both dominant and chromatically floating. In symbols you may see forms like C+add♯9 or Caug(add♯9).
Start from an augmented triad: 1-3-♯5. Then add the sharp ninth above the root: ♯9. In C this can be voiced as C-E-G♯-D♯. Because multiple altered tones are present, spacing is crucial: if all notes sit too close, the chord can become harsh rather than musical.
Use this chord when you want intense harmonic color without fully committing to a classic altered dominant stack. It works in fusion, cinematic harmony, modern jazz, and advanced pop writing where chromatic tension is part of the character. It can also function as a passing sonority between more stable dominant or tonic structures.
Keep the guide shape clear in one hand (or guitar grip), then add ♯9 as a top color. Give altered tones enough register separation so they speak clearly. Resolve one altered tone by semitone to make the progression feel intentional and controlled.
| Interval | semitones | Note | ||
|---|---|---|---|---|
| 0 | E♭ | |||
| 4 | G | |||
| 8 | B | |||
| 15 | F♯ |