The blues guitar scales are really based off of the pentatonic scales with one extra note added. We call that extra note the “blue note” because it gives the pentatonic scale its obvious “bluesyness.” The only real difference between the scales on the guitar and the same scales on any other instrument is the fact that there is more than one way to play them on a guitar. This is due mostly to the fact that the guitar is a stringed instrument and there are at least 3-5 ways to play any unique note.
The minor pentatonic scale is created using the root (or 1), flatted 3rd, 4th, 5th, and flatted 7th of a major scale. Notice that there is no 2nd or 6th scale tone used. There’s an interesting reason for that but it requires a substantial amount of music theory to explain it and this isn’t really the place for that.
To create the minor blues scale we take the minor pentatonic scale and add a flatted 5th (or sharp 4) to it. In the key of A, this creates a scale with the notes A, C, D, Eb, E, and G in it. Some people don’t differentiate between the minor and the major blues scales. If someone calls a scale a blues scale, assume they mean the minor version.
A major pentatonic scale is created with the 1st (root,) 2nd, 3rd, 5th, and 6th tone of a major scale. In C that would be C, D, E, G, and A. To make it a major blues scale you add a flatted 3rd which gives you C, D, Eb, E, G, and A in the key of C.
Notice that the rule governing relative major and minor keys/scales is also in effect here. If you look at the keys of A minor and C major, which are relative, meaning they contain the same notes, you’ll see the same group of notes.
The A minor blues scale is A, C, D, Eb, E, and G. The C major blues scale is C, D, Eb, E, G, and A. Same notes, different starting point. This sort of thing happens all the time in music. This is of particular interest if you’re playing blues lead guitar because you can see that your blues guitar scales really do double duty. Once you learn one pattern, it’s really useful for 2 keys, one major and one minor.
So how to we apply this scale to a standard 12 bar blues chord progression? What’s cool is that the simplest approach is really simple. Whatever the first chord of the chord progression is, let’s say it’s A7, use that minor blues scale to solo over the song. There’s no need to change scales at any time.
Keep in mind that this is only one possible approach, and in many cases it’s not the best approach. There are several ways to play over a 12 bar progression, or any other kind of chord progression. Many of these approaches use some combination of major and minor blues scales.
It is easy to find the 5 “boxes” or patterns of the blues scale on the internet. A simple search should turn up hundreds of choices. Once you learn the blues scales and have them under your fingers. You’ll want to start jamming with them and learning how to make the sounds you want to hear.
For more blues guitar lessons and help with your blues guitar scales, check out Playing Through The Blues, my blues lead guitar course.
Post by: Griff Hamlin