B♭7♯9 8-string bass chord

How to play B♭7♯9 on 8-string bass

The most common way, the first shape above: your index finger on the A string at the 1st fret, your middle finger on the G string at the 1st fret and your ring finger on the C string at the 1st fret. Let the D and F strings ring open. Don’t play the F♯, B and E strings.

From the F♯ string x x x 1 0 1 1 0 (x: not played, 0: open)

What notes are in B♭7♯9?

B♭7♯9, B♭ dominant seventh sharp nine, is B♭, D, F, A♭ and C♯: the root (B♭), the major third (D), the perfect fifth (F), the minor seventh (A♭) and the sharp ninth (C♯). Its formula is 1 3 5 ♭7 ♯9.