Dominant 7 Chords – C, A, E, D Shapes – I IV V – 12 Bar
Dominant 7’s have a distinct sound. They are most always in position V for any Major key center. They are Major triads with a flat 7 (R 3 5 b7). For a style like the blues, Dominants can be used in positions I, IV, and V. In this instance, the I & IV chords are non-diatonic to their own key, but this is one way we get the blues sound.
We first get these shapes in the hands. Our maps show voicings built from a C, A, E, and D chord shapes.
Once we can fret, them, we move them around. Any fully fretted version of a chord can be moved, and maintain the same quality (in this case, dominant 7), and have sonic integrity. The timbre changes along the string plane, as strings do, so there are limits to how high we might use a shape. Open strings can also be entered into the mix, depending on fingerings and position. A good example…move the C shape to P5. There, it is E7, so both 6 & 1 strings open, work.
When we move a shape to a new position (fret number), the root changes, but the type (quality) stays the same. 12 for 1.
Linear and the Neighborhood
Practice fretting & moving a single voicing type linearly. Then practice playing in a neighborhood, say positions 1 through 3, then practice the 8 to 10th position neighborhood (this means mixing forms). Then, use the progressions provided below to play 12 bar.
A tritone is an interval of a diminished 5th (or augmented 4th). It is 6 half steps. 6 half steps are 3 whole steps. 3-steps = tri-tone. Tone is sometimes used in music to mean a whole step (I Love Guitar attempts to avoid this double/triple/quadruple meaning).
The neighboring aspect to the tritones is very interesting. You could play the blues and get the sound with just these intervals. Blues guitar chords typically include this interval (dominants 7ths definitely).
The Roman numerals indicate root movement. To play in a neighborhood, follow the I, IV, and V. We always want to know where the roots are located. Root movement gives directionality to harmonic rhythm. Follow the roots.
12 Bar Progressions
Basic 12 bar blues progressions provide a basis for some forms of rock music, country and jazz. The blues form provides a solid foundation to learn to play tunes and to follow a song form. The structure can be used for any type of song. The variety and types of blues music in the world is truly astounding.
For blues to be blues, certain voicings (chords) and rhythms need to be sounded [for Major keys, this means Dominant type chords, as shown below]. We start with the most basic form, and will make modifications to make the 12 bar progressions more interesting [and more in line with what is most popularly utilized]. For more on this, see our 12 bar session in the path.
This progression is a very basic from of the 12 bar blues. It’s a whole bunch of I chords [I = the key we are playing in].
The term bar is another word for measure. Bar and measure both mean a grouping of beats. In the example above, the beat grouping is 4. There are 4 beats per measure (bar) in this exercise. Bars are created or separated by bar lines (the vertical lines).
The slash marks are a visual substitute for the quarter note (in 4/4 time) [not to be confused with slash chords]. Since the slash mark is a quarter note, it naturally represents eighth notes (strum down-up or down-down for each slash).
You can also play triplets (rounded feel of 3 strums per beat) in place of each slash [ / = 1-la-li, trip-o-let, or 1-2-3]. To get the blues shuffle rhythm, you play triplets, but miss the middle strum [ / = 1- -li, trip- -let, or 1- -3]. When we do this, this is called swinging the 8ths. Try playing triplets, & swung 8ths all down strumming.
The above progression can be a blueprint or a template for 12 bar. We can play the progression in any key (any of the 12 tones can be the I).
I IV and V chords in All Keys
These are triads, but we can use Dominants as shown in our progressions examples.
Changing bar 10 to the IV chord
After playing the simplest form of the blues, we can start making some changes. Our first change is measure 10. Going forward, we will keep any previous changes.
With this change, the 10th measure is the IV chord rather than the V. This creates a bit more interest in our harmonic rhythm.
Changing bar 12 to the V chord
With this change, the 12th measure is the V chord rather than the I. This gets us on the path of theturnaround. A turnaround is a creative & common way to get back around to the head, or the beginning. It involves a harmonic movement which leads the player & listener back to the beginning. The turnaround typically begins in measure 11.
Quick Four or Quick Change
With this change, we are plugged right into one of the most common 12 bar progressions, the Quick Change or Quick Four, titled for the quickness which the IV chord arrives (measure 2).
At playing gatherings, we see the Quick 4 quite often (even with a further alteration – the complete turnaround).
It is important to listen & follow the changes of blues tunes. With time and experience, we can listen to blues tunes, without the guitar, and hear the changes ["it just moved to the IV chord, now the V" - etc.]. There are also 8 & 16 bar forms.