7th Chords

• An extension of triads by adding another 3rd onto the stack.
• With the additional note there are many more tonalities of 7th chords than there are with triads.
• All contain some kind of Root, 3rd, 5th, and 7th.


Some of the more common 7th chords
(below using C roots for examples)

 Tonality   Chord symbol   Chord Tones   Notes 
 Major 7th   C7   R   3   5  7    C   E   G   B  
 Minor 7th   C-7   R  3   5  7    C   E  G   B  
 Dominant 7th   C7  R   3   5  7    C   E   G   B  
 Minor-Major 7th   C7  R  3   5  7    C   E  G   B  
 Half-Diminished 7th   C7  aka  C-7(5)   R  3  5  7    C   E  G  B  
 Altered Dominant   C7+  aka  C7(alt)   R   3  5  7    C   E   G  B  
 Diminished 7th   C7   R  3  5 7    C   E  G  A  

• 7 (aka 7) is the enharmonic equivalent of M6.
• There are a slew of altered dominant chords, above is just one example.