Voice leading on the guitar is a technique where a set of chord changes includes notes that lead from one chord to the next. Augmented chords are also used to connect major triads to 6th chords, as in the progression I-Iaug-I6.The augmented chord connects I and I6 with a chromatic line. The 5th of the I chord moves to the 6th of the I6 chord through a sharpened 5th.
Here is this progression in C major with the addition of a I7 chord at the end: C-Caug-C6-C7. You see the chromatic line G-Gs-A-Bf on the 3rd string of the first three measures.
You can see this in Chapter 10, Video Clip 26: Augmented Chromatic Voice Leading.
Take a close look at the pitches. C is built out of the pitches C-E-G; Caug is built out of C-E-Gs; C6 is built out of C-E-A; and C7 is built out of C-E-G-Bf. See how this progression naturally gives rise to the chromatic line G-Gs-A-Bf? In measures 1 through 4, this line appears on the 3rd string. In 5 through 8, this line appears on the 2nd string.
Many songs use augmented chords in voice leading. Here are just a few popular examples:
“Baby Hold On” by Eddie Money uses an augmented chord in the verse. Built out of the chords D and Daug, the augmented chord here comes in on the second half of each line of the verse, creating a sense of harmonic tension that resolves back into the D major chord at the beginning of each new line.
“Because” by The Dave Clark Five has the chords G-Gaug-G6-G7 at one point and augmented chords as dominants with G-Gaug-C-Cm-G and D-Daug-G at another.
“It’s All Been Done” by Barenaked Ladies has the following chord progression in the bridge: D-Daug-D6-D7-G.
“(Just Like) Starting Over” by John Lennon opens with A-Aaug-A6-Aaug.
“Laughing” by The Guess Who has the progression A-Aaug-A6-A7-Dmaj7-Dm7-Csm7-E.