Db Dominant 7th (Db7)
Also written as C# Dominant 7th (C# and Db are the same key).
Notes in Db Dominant 7th
Inversions
Same notes as Db Dominant 7th, 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 (Db7/E#)
2nd inversion
G# in the bass (Db7/G#)
3rd inversion
B in the bass (Db7/B)
Open voicings
A close-position chord like Db Dominant 7th 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
G# on the bottom
Drop 3
E# on the bottom
Db Dominant 7th consists of C#, E#, G# and B, played at the same time.
A major triad with a minor seventh stacked on top, this is the workhorse chord of blues and functional harmony. Hiding between its third and seventh is a tritone, the same restless interval that gives the chord its itchy pull toward whichever chord sits a fifth below.