For any bass player, the pentatonic scale is one of the most important bass guitar scales to know.
What is a pentatonic scale? A pentatonic scale is any scale that contains five notes. The two most popular pentatonic scales are the major pentatonic and the minor pentatonic.
The minor pentatonic scale is constructed of the root, minor third, fourth, fifth, and minor seventh scale degrees. In A, that would give you these notes: A, C, D, E, and G. It’s like an Am7 arpeggio with the fourth (D) added. Another way to look at it is the Dorian, Phrygian, or Aeolian modes with the second and sixth scale degrees removed.
A major pentatonic scale is constructed of the root, second, major third, fifth, and major sixth scale degrees. For example, a C major pentatonic scale is built of the notes C, D, E, G, and A. I like to think of it as a C major arpeggio with the major second and major sixth degrees added. You can also find it by taking the Ionian, Lydian, or Mixolydian modes and omitting the fourth and seventh scale degrees.
Do you notice any similarity between the C major pentatonic and A minor pentatonic? That’s right, they are both made of the same notes. Any major pentatonic scale will have the same notes as a minor pentatonic scale a minor third (three half-steps or frets) below it, and any minor pentatonic scale will have the same notes as a major pentatonic a minor third above it.
Though often the first step, knowing the pentatonic scales is essential for mastering bass guitar scales.