Major pentatonic
Five notes, without the 4th and 7th degrees: in C, C D E G A. It contains no half steps, so no note truly “clashes” over the main chords: for this reason it is the most singable scale in pop, country and K-pop.
Minor pentatonic
The same notes started from the relative: A C D E G (1 b3 4 5 b7). It is the scale of rock riffs, sung rap melodies and many trap toplines.
Blues scale
Minor pentatonic plus the blue note b5: A C D Eb E G. The Eb is used in passing (D–Eb–E) or with bends. There is also the major blues: C D Eb E G A (major pentatonic with the b3 as a passing tone).
How to use them
- Over an Am F C G loop the A minor pentatonic works over everything: safe hooks, R&B vocal runs.
- Over a blues in C (C7 F7 G7) the C minor blues scale over major chords creates the typical friction between b3 and 3.
- In R&B melismas you descend quickly through the pentatonic (e.g. A G E D C), closing on a chord tone.
- To vary: shift the same pentatonic over another chord (the G pentatonic over Cmaj7 gives 5, 6, 7, 9, 3: a Lydian-modern sound).
Real example
The riff of “My Girl” (The Temptations, 1964) is built on the major pentatonic; that of “Smoke on the Water” (Deep Purple, 1972) uses the minor blues scale, with the chromatic b5 that makes it unmistakable.