C Altered seventh

The altered dominant symbol alt (often written 7alt) names a dominant-seventh family chord whose upper extensions are treated as fully chromatic—commonly including combinations of ♭9, ♯9, ♭5/♯5, and ♭13—while the tritone skeleton between 3 and ♭7 remains the engine of resolution. In jazz practice, players often draw pitch material from the half-whole diminished scale (or related super Locrian thinking) to improvise and voice the chord.

Construction

Core dominant frame: 1-3-♭7 plus altered upper tones chosen by context. The exact spelling is flexible because “alt” is a function label: the bass and voice leading tell you which alterations are foregrounded.

Usage

Primary target is V7 of a minor tonic or any dominant that wants maximum tension before resolution, including tritone-substitute situations where the bass implies dominant function.

Examples

• Minor-key ii–V–i cadences with a heavily altered V7
• Turnarounds and backdoor progressions in jazz standards
• Modern R&B and neo-soul reharmonizations for chromatic approach chords

Play

Keep the guide tones (3 and ♭7) clear, avoid mud by choosing a small set of alterations per voicing, and resolve altered tones by half step into chord tones of the destination.