The Basis of Blues
A 12 bar blues is a must-know for any aspiring jazz musician. It consists of 12 bars, each having a dominant scale that corresponds to it. A dominant scale is a regular major scale, except that the 7th note is lowered a half step. When beginning, you're going to want to stay around the chord tones of the scale, those being the 1st, 3rd, 5th and lowered 7th note of the scale. These are sometimes called "safe notes". You could also lower the 3rd of the scale a half step, creating a minor 3. Be sure to resolve to the major three after, for a hip sound. There are lots of other notes that you can add, to increase tension, like flat 9 and flat 5, but always be sure to keep your solo moving forward and to resolve your tension notes. A typical 12 bar blues pattern will look something like this. Remember, every time a number is separated by a comma, that means it lasts for four beats, or one whole bar.
If we are going to play a B flat blues, then this is what the chord structure would look like:
Bflat7, Eflat7, Bflat7, Bflat7, Eflat7, Eflat7, Bflat7, Bflat7, F, Eflat7, Bflat7
For the Bflat bars, you'd use this scale: Bflat,C,D,Eflat,F,G,Aflat,
For the Eflat bars, you'd use this scale: Eflat,F,G,Aflat,Bflat,C,Dflat,
For the F bar, you'd use this scale:
Or a C blues: F,G,A,Bflat,C,D,Eflat
For the C7 bars, you'd use this scale: C,D,E,F,G,A,Bflat
For the F7 bars, you'd use this scale: F,G,A,Bflat,C,D,Eflat
For the G7 bar, you'd use this scale: G,A,B,C,D,E,F
There are some variations to this pattern. You could add what's known as a 2,5 turnaround, which would look like:
The minus in front of the 2 means that it is a minor scale, instead of dominant.
There are a lot of books out there that come with CDs with rhythm sections playing all sorts of progressions. One that I would recommend above all else is Jamey Aebersold's Volume 1.
To listen and learn from some of the greats soloing over a 12 bar blues, check out these links.