Blues musicians sing and play in a scale that is like a major scale but with ambiguous third, seventh, and sometimes sixth degrees. The variable degrees tend to be more often minor than major, but what really distinguishes blues music is the fact that the harmony is always derived from the major scale, and the often-lowered variable degrees in the melody clash with the harmony. This makes the blues scale somewhat different from the major and minor scales, in which the harmony is formed from the scale degrees.
The above paragraph is from a very good book called “Exploring Theory with Practica Musica”. Practica Musica is a computer program that allows musicians to practice ear training and theory at all levels. The book doesn’t go too far into the blues because it is very hard to explain from a theoretical point of view. Blues pretty much breaks the rules of whatever you have learned about ‘proper composition’. I’ve heard different stories about how someone discovered the blues. It’s been said that someone was singing flat and the blues was formed. The clash of the minor 3rd against the major 3rd in the harmony is one distinct aspect of the blues and the blues scale. There are many many ways to clash altered tones against a harmony but no other style of music has seemed to use it so effortlessly as the blues. It’s as if those notes go together even though logically speaking they don’t. It’s easy to teach beginners the difference between blues scales and major scales by comparing them one after the other. 99 percent of people can very easily differentiate between major scales and blues scales when played against the same harmony. Piano players should learn major scales and blues scales in their right hand and play them to the same Major scale accompaniment in the left hand. Blues accompaniments are derived from classical theory mostly using I, IV, and V chords. Harmonies are very commonly altered and extended to I7, IV7, and V7. A major scale or major pentatonic scale in the same key can also be played along to the extended 7th harmony. Blues musicians explore a freedom of melody and harmony that still holds onto a very high respect for the classical form. Rock music naturally uses many aspects of classical and blues. So does anyone out there have stories of where the blues came from? Let us know it the comments.
Posted by Musicguru