Three note chord voicings (also known as ‘shell’ chords) are very useful harmonic forms to know. They are often used in jazz and blues music where you require simple sounding voicings without extensions or alterations being added.
In the examples below you will see multiple three note voicings with a root note on either the low E string, or on the A string. You will also see that these chords generally have no 5th degree present.
If these chord forms are new to you, my suggestion would be to first learn the voicings with a root on the 6th (low E) string and then learn the others with a 5th string root.
Once you have learned the basic voicings, you can then play the next examples which cover the harmonisation of a major scale. The first harmonisation covers the diatonic chords within the G major scale (using 6th string roots) and the following (using 5th string roots) covers the C major scale.
Now that you’ve played through the first few examples above, you can play the final two exercises which are based on a I VI II V progression. The penultimate example is diatonic sequence and then this is altered to four dominant seventh chords based on the same root progression. This is a common substitution in both jazz and blues music.
Once you have a good working knowledge of the above three note chord voicings, try to ‘comp’ (play the chords as accompaniment) through some popular songs/jazz standards using them. You could use something like a Real (Fake) Book for this.
Finally, here is a PDF copy of the above exercises in case you want to print the music out:
Have fun practicing these three note chord voicings!