The mixolydian scale — known as the dominant scale consists of ascending pattern:
WWHWWHW
Mixolydian scale is the 5th mode in the major sacle family and contains the same notes as the major scale a perfect 5th below.
You m ay think of the mixolydian scale as a major scale with the 7th note lowered a half step.
This scale is typially used when improvising over unaltered dominant chords, such as dominant 7th, dominant 9th, dominant 13th and dominant7th suspended 4th chords.
G7 — 1 3 5 b7
G9 — 1 3 5 b7 9
G13 — 1 3 5 b7 9 13
G7sus4 — 1 4 5 b7
When the 11th is used (4th degree) it is suspended in place of the 3rd creating a dominant 7th sus4 chord.
Sometimes an aug 11th is added to the Dom7, but this color is derived from the dominant scale.
In Major and minor keys —
a. dominant chord usually functions as a V chord
— a strong tendency to resolve to the I (tonic) chord.
b. it may also function as a secondary dominant chord acting as a V chord to a chod other than the I chord.
— eg. in major keys — we find:
- secondary dominants built on the first scale degree of the major scale (V7 of IV)
- the second degree (V7 of V)
- the third degree (V7 of vi)
- the sixth degree (V7 of ii)
- the 7th degree (V7 of iii)
— eg in minor keys, we find:
- secondary dominants built on the first natural scale (V7 of vi)
- the second degree (V7 of V)
- the third degree (V7 of VI)
- the fourth degree (V7 of VII)
- and lowered 7th or subtonic degree (V7 of III)
although a dominant chord typically functions as wither a V7 chord or a secondary dominant, in jazz it can occasionally act as a tonic chord as in the case of the blues progression.
With the exception of V7sus4, the 4th note in the mixolydian scale is best used as a passing tone over V7 chords.
–the 2nd, 3rd, 6th 7th scale degrees have the richest color.
Common variant of the mixolydian scale — the bebop 7th scale
— it inserts the major 7th as a passing tone between the b7 and the octave.
Bebop 7th scale — can be used over unaltered dominant chords as well as the minor 7th chord a perfect 4th below the first note of the scale.