Bb Augmented Seventh Chord

Chord Tones: Bb Augmented Seventh Chord

Symbol: aug7, +7, 7♯5 — Formula: 1-3-♯5-♭7

Chord Notation

Roman numeral (e.g. I, IV, V) and Nashville Number notation are key-dependent. See Keys pages for chord function within specific keys.

Inversions

Harmonic Function

The Bb augmented seventh chord commonly functions as the subtonic (♭VII) in C major or subdominant in F major. Its harmonic role varies by key — in major keys it provides extended harmonic tension.

The augmented seventh chord adds a minor seventh to the augmented triad, combining the restlessness of an augmented fifth with the tension of a dominant seventh. Used for maximum harmonic tension.

Common Progressions

The Bb Augmented Seventh Chord frequently appears in these progression patterns (shown in Roman numeral notation relative to key):

• V+7-I
• I+7-IV

Songs Featuring the Augmented Seventh Chord

Well-known songs where the Bb Augmented Seventh Chord — or this chord type — plays a prominent role:

• Whole Lotta Love – Led Zeppelin
• Come Together – Beatles (chord variant)
• Spanish Key – Miles Davis

Tuning Frequencies Across Temperaments

Frequencies shown at A=440 Hz. View full temperament data for any note.

Scales Containing the Bb Augmented Seventh Chord

These scales include the Bb Augmented Seventh Chord as a diatonic or characteristic chord: