Identifying augmented chords

Augmented chords don’t come up much, but they are on the aural skills syllabus, and they have that specific quality that no other harmony can create. Their uncanny zero-gravity quality is the result of their symmetry. Any note in an augmented triad could function as its root. When you write the augmented chords on the chromatic circle, you quickly discover that there are only four possible ones, shown in the image below.

The one on the top left is C+, E+ and G#+/Ab+. The one on the top right is C#+/Db+, F+ and A+. The one on the bottom right is D+, F#/Gb+ and A#/Bb+. Finally, the one on the bottom left is D#/Eb+, G+, and B+.

There is a close relationship between augmented chords and the whole tone scale. If you play every alternating note in either whole tone scale, you get augmented triads. Also, any two augmented triads whose roots are a whole step apart produce a whole tone scale. And you can extend your augmented chords with whole tone scale notes.

The most common use case for augmented chords in Anglo-American pop is as a variant on the V chord. If you are in C, you can use G+ instead of G. It has nice voice leading! G stays on G, B leads up to C, and D-sharp leads up to E. You can also add F to the G+ chord to make G+7, also known as G7(#5). You can think of G+ as coming from C harmonic minor; it has a minor-ish quality to it even when it resolves to C major.

The Beatles used lots of augmented chords as dominants to achieve a nostalgic 1950s sound. The paradigmatic example is “Oh! Darling”. It’s in A, and it begins with E+, acting as an E chord with a sharp fifth.

This intro is a nod to Chuck Berry tunes like “No Particular Place To Go”.

A couple of songs after “Oh! Darling” on Abbey Road comes “I Want You (She’s So Heavy)”, which uses augmented V chords in a more complicated way. The intro section is in D minor. It ends on a dramatic hanging A+ chord that you expect to lead back to Dm. But no, instead it’s followed by the Am chord that begins the verse section (and the meter changes to 4/4, too.) At 2:06, the A+ chord functions the way you’d expect, leading into Dm on the next bar.

Stevie Wonder combines augmented chords with whole tone scale on “You Are The Sunshine Of My Life.” The tune is in B, and the first chord is Bmaj9. The second chord is F#7(#5), and Stevie’s riff walks up the F# whole tone scale in thirds.

Augmented chords are more prevalent in late Romantic and modern classical music than they are in pop, and you can hear the influence of those styles on Hollywood film composers, especially in the suspense and horror genres. Bernard Herrmann’s “Vertigo Suite” starts with an arpeggiated D+ chord.

Charles Cornell points out that augmented chords are also the sound of space.

Sometimes you hear augmented chords emerging out of voice leading in chromatic basslines or countermelodies. The “Stairway to Heaven” intro is the most common cliche here. It’s a chromatic descending bassline in Am. The second chord is usually written as Am/G#, but you could understand it to be G#+, an inversion of E+.

“Life On Mars?” by David Bowie has several interesting examples of augmented chords emerging out of chromatic voice-leading.

Listen to the line “but the film is a saddening bore” at 0:42. On the word “film”, the chord changes from Ab/Eb to E+. On the word “bore”, the chord changes to Fm. You can think of the E+ in this context as an inversion of C+, the dominant chord in F minor. On “she could spit in the eyes of fools”, Bowie uses the same idea transposed up a fourth: Db/Ab to A+ to Fm. In the chorus at 1:04, on the line “oh man, look at those cavemen go”, Bowie uses a similar idea in reverse: Gm to Gb+ to F.

“Baby Hold On” by Eddie Money is an unusual variant on the chromatic line cliche. The main groove alternates D and D7(#5). It’s the beginning of an ascending line, but it stops ascending after the second chord. Finally, at 0:46, Eddie Money does ascend the rest of the way up the chromatic scale.

You can hear a similar idea in the intro to “Mamma Mia” by ABBA, which alternates D and D+.

Wayne Shorter’s “Ju-Ju” begins with a long stretch of B7#5, with B whole tone scale on top.

Augmented chords are important in John Coltrane’s music, not as a surface-level feature, but as an underlying organizational principle. “Giant Steps” cycles rapidly between the keys of B, Eb and G, whose tonics form an augmented triad. While Coltrane didn’t play this tune for long, he did use the augmented-triad-tonic scheme in his improvising throughout his life.

This is way outside the scope of a level two aural skills class, but in just intonation, augmented chords don’t have the symmetry that they do in twelve-tone equal temperament. The just major third is a frequency ratio of 5/4. So if your root note is C at 1 Hz, going up a major third gives you E at 5/4 Hz. Going up a major third from E gives you G-sharp at 25/16 Hz. And going up a major third from G-sharp gives you, uh, B-sharp at 125/64 Hz. Shouldn’t you be back at C, an octave up from the root at 2 Hz? Not in just intonation, you shouldn’t. In twelve-tone equal temperament, we tune our major thirds a little sharp so that when you stack three of them up, B-sharp comes out to the same pitch as C.