Blues Scales

A blues scale is a scale built with six notes derived from the major and the minor pentatonic scales.

Many people think there is only one blues scale, (the minor blues scale).

This is a mistake, there are several blues scale which can be classified this way : 

Hexatonic Scales or Six-Notes Blues Scales.

The minor blues scale with a b5

This is the minor pentatonic scale (1-b3-4-5-b7) including a flat ninth (b5).

This is the most widely used of the blues scales.

It is built with a root (1), a minor third (b3) also considered as flat eleventh (b10) or sharp ninth (#9), a fourth (4 or 11), a flat fifth (b5 or #11) which is the blue note and a minor seventh (b7).  

​​​​​​​The minor blues scale with a major 3rd (3)

This one contains the same notes as the minor pentatonic scale but with a supplementary note, the major third (3).

The formula is root (1) - minor third (b3) - major third (3) - fourth (4) - fifth (5) and minor seventh (b7).

The minor blues scale with a seventh (7). 

There are two possible combinations. Root (1) - minor third (b3) - fourth (4) - fifth (5) - minor seventh (b7) - and seventh (7). or  (1 - b3 - 4 - b5 - 5 - 7)

The voodoo blues scale

This is the same scale as the minor blues scale but with a sixth (6). Giving the formula (1 - b3 - 4 - b5 - 5 - 6).

The major blues scale

This is the major pentatonic scale (1 - 2 - 3 - 5 - 6) with an added b3 also named b10.

It consists of a root (1), a second (2), a minor third, the blue note (b3 or b10), a major third (3), a perfect fifth and a major sixth (6).

Heptatonic scale

This composite blues scale consists of eight notes, including the three blue notes. Formula is 1 - b10 - 3 - 11 - b5 - 5 - b7 - 7.

Nonatonic scale

The composite blues scale

The composite blues scale or Mixolydian blues scale or mixo blues scale is built with nine notes.

As its name implies, it is a mix of the minor blues scale (1 - b3 - 4 - b5 - 5 - b7) and the Mixolydian mode 1 - 2 - 3 - 4 - 5 - 6 - b7 (or the major pentatonic scale).

This scale combines major & minor pentatonic sounds, here is the formula : 1 - 2 (9) - b10 (or #9) - 3 - 11(4) - b5(#11) - 5 - 13(6) - b7.