C# Dominant 11th (C#11)
Also written as Db Dominant 11th (Db and C# are the same key).
Notes in C# Dominant 11th
Inversions
Same notes as C# Dominant 11th, with a different chord tone as the lowest note. Useful for smoother movement between chords instead of jumping around the keyboard.
Root position
C# in the bass
1st inversion
E# in the bass
2nd inversion
G# in the bass
3rd inversion
B in the bass
4th inversion
D# in the bass
5th inversion
F# in the bass
Open voicings
A close-position chord like C# Dominant 11th can sound cluttered in the middle of the keyboard. Jazz players open it up by dropping one note down an octave, spreading the same notes wider without changing the chord.
Drop 2
C# on the bottom
Drop 3
B on the bottom
Press C#, E#, G#, B, D# and F# together on the keyboard and you're playing C# Dominant 11th.
A dominant ninth chord extended with an eleventh, though in practice pianists often leave the third out since it sits a half step below the eleventh and the two can clash. What's left has a fuller, more suspended color than a plain dominant chord, and it turns up constantly in funk and modal jazz.