Let's take a closer look at the fragment for a dominant 7th.
This is probably the most important fragment to know if you
are playing jazz and blues.
Note
some interesting observations about this shape. It is called
a tritone and consists of the 3rd and b7th of a dominant
chord. It is called a tritone because it spans the distance of
3 whole steps, splitting the octave in half at an interval of a
b5th . It is perfectly symmetrical. It is a very easy shape to
locate on the fretboard because of the way it inverts itself,
always in that familiar triangular shape. It is also very easy
to add tensions to that shape. Using these two tritones:
we will add
the 9th and 13th as well as the altered tensions b9, #9, b5,
and #5:
All of the tensions
are right there on the B and E strings. Once you find the
tritone fragment for your dominant chord, it's not too difficult
to begin to visualize where the 9th and 13th are. From there,
it's just a matter of flatting or sharping to get the altered
tensions! This is great in a comping situation where, for
example, while comping thru a blues, the soloist plays a
line which incorporates an altered tension. If you are already
sitting on the tritone shape for a dominant chord when this
happens, you can immediately respond to the soloist by
quickly injecting that same tension the soloist had just
played. This is great for your ears! I often comp on the
tritone, just waiting for an altered note from the soloist.
When you jump on it, everyone will notice what big ears you
have!
