There are four types of 7th chords:
- Major 7th
- minor 7th
- Dominant 7th
- minor Major 7th
Chords are made up of the 1,3,5 formula, so using the C Major scale...
Starting from C: C,E,G,B = 1, 3, 5, 7.
Starting from G: G,B,D,F = 1, 3, 5, b7.
Starting from A: A,C,E,G = 1, b3, 5, b7.
So there are 2 variables: the 3/b3 and the 7/b7.
- A 3 can have a 7
- A 3 can have a b7
- A b3 can have a 7
- A b3 can have a b7
No more combinations available*.
- Major 7 (M7) = 1,3,5,7
- minor 7 (m7) = 1,b3,5,b7
- Dominant 7 (7) = 1,3,5,b7
- minor Major 7 (mM7) = 1,b3,5,7**
*There are a few more, but they involve changing the 5th, too (Dimished 7th and half Diminished). They are reserved for a different lesson file…
**The minor Major 7 (mM7) chord does not appear in the Major Scale. Instead you can find it in the Harmonic minor (1,2,b3,4,5,b6,7) and Melodic minor (1,2,b3,4,5,6,7) scales.