Bb7sus4

Bb7sus4 is Bb, Eb, F and Ab, a dominant seventh suspended fourth. The shape this page opens on is written x13141, lowest string first.

Note by note. Bb is the root, Eb is the fourth, F is the fifth and Ab is the flat seventh.

Also written Bb7sus or Bb dominant 7 sus 4. The same chord either way; which spelling you meet depends on who wrote the chart.

There are 6 common shapes for Bb7sus4 on the guitar, and 29 derived voicings in 4 families.

One note away. Change a single note of Bb7sus4 and you have Bbsus4 (with one note taken away), Bbsus2sus4 (with one note moved), Bbm7 (with one note moved), Bb7 (with one note moved) or Bb11 (with one note added).

In which keys. Every note of Bb7sus4 belongs to C minor (the ♭VII), C# major (the vi), Eb major (the V), Eb minor (the v), F minor (the iv), F# major (the iii), Ab major (the ii) and Bb minor (the i).

The common shapes, written lowest string first: x13141, xxx344, xx3344, 686866, x-x-8-10-9-11, x-13-13-13-11-11.

Under the hand. None of the shapes for Bb7sus4 uses an open string, so every one of them is movable; the lowest sits at the 1st fret. 3 of the 6 need a barre. Together they cover the neck from the 1st fret to the 13th.

Shell. 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. Bb7sus4 has x111xx, 666xxx, x-13-13-13-x-x, x1x14x, 6x68xx, 6x11xx, x-13-x-8-9-x.

Drop 2. A close-position chord with the second voice from the top lowered an octave. Sits on four adjacent strings. Bb7sus4 has 1111xx, xx3344, xx6866, 6868xx, x8889x, x-x-13-13-11-13, 13-13-13-13-x-x, x1314x.

Drop 3. The third voice from the top lowered an octave. The dropped voice becomes the bass, which is why a string is skipped. Bb7sus4 has x1x141, x6x364, 4x334x, x8x896, 6x686x, 11-x-8-10-9-x, x-11-x-10-11-11, 13-x-13-13-11-x.

Open string. An open string left ringing against a fretted grip. Because it costs no finger, it sounds a note the closed shape has none left for -- a tension on top, or a pedal root underneath. Either a familiar grip with open strings added, or a shape so sparse the open strings carry the chord. These belong to their key rather than to a shape, so D, A, G and E have many and Eb a handful. Bb7sus4 has 6660xx.

Tensions. A shell of Bb7sus4, root, third and seventh, leaves a string free, and the tones that belong over it are the 9 (C) and the 13 (G).

What kind of chord this is. Bb7sus4 is a suspended chord — root and fifth, with a second or fourth where the third would be — or nothing at all. suspended and power chords on every root, and what they are for.

The common shapes and the derived voicings come from different places, and both are explained in where the chords and the theory come from.