Bbsus4 delays the note that would make sound settled. It holds in the third’s place, giving Bb, Eb and F.
The pair below catches the moment before resolution: the major third rises to the fourth while the outer notes hold.
The 4th falls by one fret to the major 3rd. The root and fifth stay the same.
Let the fourth fall and arrives through the classic 4–3 motion. Leave it where it is and the suspension becomes its own chord.
Also written Bbsus or Bb suspended 4th.
Bbsus4 holds the tonic over into the V, where the third should be, then lets it fall a step to the third. The V is the chord most often treated this way, and more often still the fourth is left hanging and never falls.
Listen for: The tonic holds into the V as its fourth, falls a half step to the third, and rises back home.
Heard in“Sunny”“In My Room”“California Dreamin’” (left hanging)
The 4–3 suspension isn’t only for the V. Bbsus4 can fall to Bb as the IV of F major, and a minor tonic can be suspended the same way.
Heard in “Honky Tonk Women” (IV), “Love Is Blue” (i)
In which keys. Every note of Bbsus4 belongs to C minor, C# major, Eb major, Eb minor, F minor, F# major, G minor, Ab major, Bb major and Bb minor.
Contains Bbsus4 and adds minor third and flat seventh.
Contains Bbsus4 and adds minor third, sharp eleventh and flat seventh.
Contains Bbsus4 and adds second, major third, sixth and major seventh.
Adds second, major third, sixth and flat seventh. The flat seventh pushes the sound toward a dominant chord.
Contains Bbsus4 and adds second, minor third, flat thirteenth and flat seventh.
The common shapes and the derived voicings come from different places, and both are explained in how this site is built.
Shows each chord the way this style would voice it, and marks which of its alternatives belong to the idiom.