Theory. Jazz chords1

The basic chords used in jazz harmony are the 7th chords.  They are:

- the major 7th
- the minor/major 7th
- the minor 7th
- the half-diminished 7th
- the diminished 7th
- the dominant 7th
- the suspended dominant 7th


So I want to make sure I understand their structure.   A 7 chord is built by stacking three 3rds on topic of one another so that the total distance between the tonic and the upper most note form the interval of a 7th.


They  can be described by a 'formula', which identifies the accidentals of each scale degree for that chord, and the semi-tone steps (or intervals names, but I won't do that here).

The 7th chords are build on triads, to let's start there:


Major triad
  Formula = 1, 3, 5
  Semi-tones = 4 - 3
  (aka, intervals of a major 3rd and a minor 3rd)
Example
  Cmaj= C, E, G


Minor triad
  Formula = 1, 3b, 5
  Semi-tones = 3 - 4
  (aka, intervals of a minor 3rd and a major 3rd)
Example:
  Cmin = C, Eb, G


Finally to create a 7th chord, an additional the 7th scale degree is added.  Here's a simple example.


Major 7th
  Formula = 1, 3, 5, 7
  Semi-tones = 4 - 3 - 4
Example
  C major 7th = C, E, G, B


Watch for a new posting which uses the same scheme to describe each of the primary 7th chords used in jazz.

In the meantime, here is rare clip of Charlie Parker, who was among those who introduced these chords to jazz.