Chord & FretBb7alt — altered dominant
Also written A#7alt — the same chord, spelled the other way.
Notes in Bb7alt: Bb – D – F# – Ab – C#Formula: 1 – 3 – #5 – b7 – #9In the formula, the numbers count steps of the major scale starting from the note that names the chord; "b" lowers a half step, "#" raises one — and a slash names the bass note.
The 7alt is not a fixed chord but an instruction: keep the root, the third and the seventh, and alter the tensions (b9, #9, #11, b13). Nobody plays them all at once — you pick two, and the tension peaks right before the resolution.
The same chord on all four instruments
Where to use it: The last dominant before the return home, above all in a minor key; the signature of jazz.
This is just one shape of Bb7alt. In Chord & Fret, you hear every shape strummed string by string, in each instrument's own voice; compare positions with their difficulty marked; and set a capo — the diagrams redraw above it. Start free. Unlock everything with Pro. Plays offline.
See the whole neck in Chord & Fret →Part of the Altered dominants family.