The blues scale is an interesting phenomenon in use and theory. It is the basis for so much music and is used by countless musicians. However, despite its wide use, many don't know it's origin, it's real application and why it sounds so great.
The blues scale is one of those things that was played first and then written down and analyzed later; much like folk music from many cultures. The best explanation of the evolution of the blues scale comes from “The History of Jazz”, by Joachim-Ernst Berendt and Gunther Huesmann. African people were brought to America as slaves bringing their own folk music and tonal language. These people were then converted to Christianity and were introduced to western classical harmony through the hymns. Over many years, these two tonal formats melded together and along with the people’s pain and suffering and the Blues was born.
Now, for some theory:
The b3rd, b5th and b7th are called the “Blue Tones”. These are the notes that make the blues sound like the blues. Therefore, the blues scale is defined as:
Root-b3rd-4th-b5th-5th-b7th. (i.e. C-Eb-F-Gb-G-Bb)
The real interesting thing about the blues scale is that, while it is technically a minor scale (note the b3rd) it is applicable over BOTH major and minor tonalities. Now, you might say, "there are notes that don't fit! It is going to sound wrong!" Understand, the blues is not happy music. The apparent "dissonance" is what conveys the pain and suffering that the people experienced. The result is the blues scale has a very distinctive sound. The good thing about this is if you use the blues scale, you will sound bluesy. The bad thing is if you use the blues scale...you are going to sound bluesy. In my opinion, unless you are in a blues band, the blues scale should be used sparingly. If not, it will be too easy to play yourself into a corner and risk being stale. A way to avoid this is to do what many players do....play the minor pentatonic...it has 2 of the 3 blue tones and is not as heavily "colored". I call it "Blues Light". This way, you can use the "full blown” blues scale as "spice".
Now for an exercise...consider the following chord progression:
| C | % | F | G | C | % | Am | G |
Make a bassline using major and minor pentatonics, minor pentatonics only and finally blues scales. Have someone play the chords while you play. Listen to the differences the each harmonic environment yields. The blues scale is quite distinguishable and when used tastefully, can add interest to your playing.
Please feel free to contact me with any questions.
Lots of luck!!!