Bbadd9 is Bb, D, F and C — Bb with the ninth added, and no seventh.
It sounds bright and ringing. No seventh at all: that is what “add” means, and it is why this sounds open where a maj9 sounds lush.

| Bb | D | F | C |
|---|---|---|---|
| 1 | 3 | 5 | 9 |
Tonic — a triad with one colour on it.
Also written Bb(add9), Bbadd2 or Bb add nine. The same chord either way; which spelling you meet depends on who wrote the chart.
The same operation one voice further down: the third voice from the top falls an octave and becomes the bass.
That leaves a bigger hole under the top three notes, so a string gets skipped: the muted string in the middle is the shape, not a mistake.
Bbadd9 has 10 of them, on strings 5-3-2-1 and strings 6-4-3-2, from open position up to the 13th — every inversion the chord has: Bb in the bass, D in the bass, F in the bass and C in the bass. The one to learn first is the C shape at the nut.
5 of them sit on strings 5-3-2-1, 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 xx87x8 — no barre and only 3 fretted notes. 1 of the 5 shapes here sits in open position. 3 of the 5 need a barre. Together they cover the neck from the 1st fret to the 13th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| x10311 | open position | Bb, root position | F | barred |
| 65x566 | 5th fret | Bb, root position | Bb | barred |
| xx87x8 | 7th fret | Bb, root position | C | all fretted |
| x-13-12-10-13-10 | 10th fret | Bb, root position | D | all fretted |
| x-13-12-x-13-13 | 12th fret | Bb, root position | F | barred |
The same notes rebuilt from scratch give 15 drop 2 voicings, each on its own page.
How you get to it. The turn that lands on Bbadd9 is Cm7 to F7 — the ii and the V of Bb — and F7 shares its third and seventh with Cm7, so the hand barely moves between them.
In which keys. Every note of Bbadd9 belongs to C minor (the ♭VII), D minor (the ♭VI), Eb major (the V), F major (the IV), G minor (the ♭III) and Bb major (the I).
Every note of Bbadd9 is in Bb major pentatonic, Bb major, Bb lydian, Bb mixolydian and Bb lydian dominant.
Change one note of Bbadd9 and you have Bb (drop the ninth), Bbsus2 (drop the major third), Bbsus2sus4 (the major third becomes a fourth), Bbmaj7 (the ninth becomes a major seventh), Bbmaj9 (add the major seventh) or Bbmadd9 (the major third becomes a minor third).
Bbadd9 is a major chord — root, major third, fifth. Major chords on every root.
On Bbadd9’s sound and use this page follows Robert Rawlins & Nor Eddine Bahha, Jazzology (Hal Leonard, 2005). 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.