Augmented Ninth

A9

interval

At a Glance

Formula:
9 augmented
Notes:
C, D#

Piano

Fretboard

eBGDAE

A compound interval - larger than an octave. Shown here within a single octave, same as its simple equivalent.

What It Is

An octave plus an augmented second (15 half steps), enharmonically equal to a minor third one octave up.

How It Functions

The 'Hendrix chord' alteration - defines the sharp-9 tension in a Dominant 7#9 chord, common in blues, funk, and rock.

Real Song Examples

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