Watch the Dyads online guitar lesson by Christopher Woitach from Jazz Textures
Up till now, everything we've done with dyads has had both pitches moving in the same direction, higher or lower. This is called similar motion, and is the most common way a guitarist harmonizes their lines. A different, and more difficult approach is to use contrary motion, where the voices move in opposite directions. One nice effect of contrary motion is the way it really separates the two voices, giving the impression of two guitars playing at once. The wider the intervals between the voices, the more pronounced the effect.
When practicing these techniques, you should focus on one at a time, working through all twelve keys, all string sets, really thinking about fingerings. The idea is to have the techniques become a natural part of your playing, so that you can choose and combine them at will when you improvise. You might have noticed that in my improvisations on this video I rarely stick to just one technique, I tend to mix them up, using whichever concept feels most musical at the time. The great thing about jazz music is the freedom to express your own personality and taste in your improvisations - a reward for all the hard work!