Seventh Chords
A seventh chord contains a triad with a seventh interval on top. If not specified the seventh will be the 'dominant' seventh, which means a major triad with a minor seventh interval above. A minor seventh chord contains a minor triad with minor seventh interval and a major seventh chord contains a triad with the third being a major third and with a minor seventh interval.
E 7
OOOOOO
1
2
1
A 7
XOOOOO
1
2
C 7
XOOOOO
1
3
2
4
1
D 7
XXOOOO
1
2
1
3
B 7
XOOOOO
1
2
1
3
4