Root, third and seventh: the guide tones fix the quality, so the fifth is dropped. That is what leaves a string free, so pick a tension to put on top.
B9#11 is B, D#, F#, A, C# and E# — B9 with the raised eleventh added on top.
It sounds wide and glassy, bright rather than tense. The ♯11 clears the major third by a whole step, so it adds height without the collision a natural eleventh makes.

| B | D# | F# | A | C# | E# |
|---|---|---|---|---|---|
| 1 | 3 | 5 | ♭7 | 9 | ♯11 |
Dominant — the lydian dominant sound.
Also written B9(#11), B9+11 or B9♯11. The same chord either way; which spelling you meet depends on who wrote the chart.
Root, third and seventh. The third and seventh, the guide tones, are what make the chord major, minor or dominant, so the fifth can go: it says nothing the symbol needs.
Three notes means a spare string, which is the real point. Put a tension on it.
B9#11 has 9 of them, on the middle four strings, the bottom four strings, the top four strings, strings 5-3-2-1 and strings 6-4-3-2, from open position up to the 13th — all in one inversion, so the bass note never moves. The one to learn first is the B shape at the nut, which is the easiest grip here.
3 of them sit on the middle four strings, so you can run the inversions up one set without changing strings — which is the whole reason to learn them as a family rather than as separate grips.
Start with x2324x — no barre and down at the nut. None of the shapes for B9#11 uses an open string, so every one of them is movable; the lowest sits at the 1st fret. 4 of the 7 need a barre. Together they cover the neck from the 1st fret to the 14th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| x21221 | 1st fret | B, root position | E# | barred |
| x2324x | 2nd fret | B, root position | D# | all fretted |
| 767667 | 6th fret | B, root position | B | barred |
| 7x786x | 6th fret | B, root position | E# | all fretted |
| 787877 | 7th fret | B, root position | B | barred |
| x-x-9-10-10-11 | 9th fret | B, root position | D# | all fretted |
| x-14-13-14-14-13 | 13th fret | B, root position | E# | barred |
The same notes rebuilt from scratch give 13 rootless voicings, each on its own page.
Tensions. A shell of B9#11, root, third and seventh, leaves a string free, and the tones that belong over it are the b13 (G) and the 13 (G#).
B9#11 is a dominant with its tension raised, so it still points at E — harder than a plain seventh does, because the altered tones sit a semitone from where they are going.
Voice by voice, B9#11 → E. 3 voices move by a semitone, and one note is common to both chords.
| In B9#11 | Moves | In E |
|---|---|---|
| B, the root | stays where it is | B, the fifth |
| D#, the major third | rises a semitone | E, the root |
| F#, the fifth | falls a whole tone | E, the root |
| A, the flat seventh | falls a semitone | G#, the major third |
| C#, the ninth | falls a whole tone | B, the fifth |
| E#, the sharp eleventh | falls a semitone | E, the root |
Every note of B9#11 is in B lydian dominant.
Change one note of B9#11 and you have B9 (drop the flat fifth), B9b5 (drop the fifth) or B13 (the flat fifth becomes a sixth).
B9#11 is an altered chord — a dominant seventh with its fifth or ninth moved. Altered dominant chords on every root.
On B9#11’s sound and use this page follows Mark Levine, The Jazz Theory Book (Sher Music, 1995). The shapes and the derived voicings come from different places, and both are explained in where the chords and the theory come from.
Shows each chord the way this style would voice it, and marks which of its alternatives belong to the idiom.