A Plus in Your Scale Arsenal: Augmented Scale ii-V7-I
A six note scale (hexatonic), formed by:
2 augmented triads a minor third apart (C-E-G# & Eb-G-B = C-Eb-E-G-Ab-B)
2 augmented triads a half step apart (C-E-G# & Db-F-A =
A Major triad and a minor triad a Maj 3rd below (C-E-G & Ab-B-Eb = C-Eb-E-G-Ab-B)
A minor triad and a Major triad a Maj 3rd above (C-Eb-G & E-G#-B = C-Eb-E-G-Ab-B)
3 min 2nds a Maj 3rd apart (C-Db, E-F, G#-A)
3 min 3rds a Maj 3rd apart (C-Eb, E-G, Ab-B)
There are also Perfect 4ths and 5ths, as well as Maj & min 6ths, plus Maj 7ths included.
Check 'em out.
One of the more interesting (and challenging) aspects of using the Augmented scale in this manner is the fact that the Augmented scale has no tritone (eg, F - B), which makes its tendencies toward normal resolution (as in Major or minor scale harmony) somewhat ambiguous.
But hey, ambiguous is good in this case; as in "inside-outside" and vice versa.
The whole first line uses the Bb (D, F#) Augmented Scale (Bb-C#-D-F-Gb-A) over
C-7b5 / F7 / Bb / Bb /
Line #1, Measure #1 - C7b5 (Parts of the chord in parenthesis):
D (9) - F (11) - Gb (b5) - Bb (b7) A (6) - Bb (b7) - D (9) - F (11).
Pretty consonant (inside), actually.
Line #1, Measure #2 - F7sus:
C# (#5) - D (13) - F# (b9) - Bb (11) - A (3) - Gb (b9) - Db (b13) - F (root).
As mentioned previously, the Augmented scale is devoid of tritones, but melodically, in this case, it still pulls toward a resolution to Bb; with the root and 3rd of the V chord being present. The Bb in the scale also supports this.
Line #1, Measures #3 & 4 - Bb Maj7
A straight up Bb Maj7 with a C# (#9 or b3) and Gb (b13 or #5) thrown in for flavor.
As the Augmented scale divides the octave into 3 equal parts, the result is 4 different Augmented scales. The exercise is transposed by ascending half steps into all 12 positions (keys), the basic scale repeating every 5th line (ie. line #1 & line #5 are from the same Augmented scale).
If you have a sequencer (Band in a Box, iReal), try practicing first with just the bass notes or bass line, then add shell voicings (3rds and 7ths).