A dominant 7 chord adds one note to a major chord: the flat seventh. The sound: tense, bluesy, restless. Wants to resolve somewhere.
Three you need to know:
- G7: the open G chord with the high E string fretted at the 1st fret (F note, the b7 of G).
- A7: open A chord with one finger removed (third on the G string left open).
- D7: D shape modified — the high E plays the open B at fret 1 fret (C, the b7 of D).
The 12-bar blues uses three dominant 7s
You already played a 12-bar blues in lesson 13 of the Beginner track. The "proper" voicing uses dominant 7 chords:
A7 | A7 | A7 | A7
D7 | D7 | A7 | A7
E7 | D7 | A7 | E7
Strum each chord 4 times. Move to the next. The b7 in each chord creates the bluesy tension that defines the genre.
Drill it
Practice metronome
80BPM
Set 80 BPM. Strum the 12-bar pattern above. Each chord gets 4 down-strums. Loop the whole 12 bars three times. That is one drill.
Most students need to slow down to 60 BPM the first day. That is fine. Get the chord changes clean, then bring the tempo up.
Beyond blues
Dominant 7s appear in country, soul, R&B, jazz, classic rock. Stand By Me (E, C#m, A, B7) ends on a B7. Twist and Shout (D, G, A) often gets played D7, G7, A7. Folsom Prison Blues is built on E7 and A7.Anywhere you play a major chord, try the dominant 7 version. You will instantly hear the difference.
Next: major 7 and minor 7 chords. The sound of jazz, soul, and ballads.