【樂理課堂】曲式：RMlg.mf4 - 12 Bar Blues Form

Learning Music With Ray- 12 Bar Blues Form.. In it, I discuss the structure and musical elements typical of this form. I then play through the basic 12 bar blues (and some basic variations) with simple block chords in the key of C major. Finally, I demonstrate several piano playing techniques that help to enhance your performance of a 12 bar blues beyond basic block chords. The 12 bar blues form is a simple harmonic progression that is played across 12 measures (or bars) of music. This harmonic progression consists mainly of the I, IV and V chords. The chords can exist as either simple triads or seventh chords, but the seventh chord version does not follow the normal structure of diatonic seventh chords. In a normal diatonic chord progression there is only one dominant seventh chord (the V7 chord). However, blues music lends itself to dominant seventh harmony. Therefore, all three chords (I, IV and V) can be played as dominant seventh chords even though this introduces pitches that are chromatic to the key.In addition to this chromaticism, blues music also is known for having loose boundaries between major and the parallel minor. Chords are often played with a minor third that slides or bends into a major third. This technique adds to the blues flavor of the sonic texture.The 12 bar blues form is used primarily in the blues style of music, but is also found in many pop, rock and gospel songs. These styles can tend to be heavily influenced by the blues style. The form is popular among musicians, because the simple repeating harmonic pattern causes it to be easy to memorize. Musicians can play most 12 bar blues songs without a lead sheet. All they need to know is the key of the song.The basic pattern for the 12 bar blues can be broken into three groups of 4 measures each. The first four measures consist of the I chord. Then there are two measures of IV and two measures of I. Finally there are two measures of V and two measures of I. ....