Unlocking the Augmented Fifth: Your Guide to Musical Tension and Color

Summary:

This article delves into the augmented fifth, a unique and colorful interval in music theory. We will explore its definition, its distinct, dissonant sound, and its crucial role in creating tension and emotional depth. By understanding the augmented fifth, you'll gain insight into the structure of augmented triads, the function of altered dominant chords (V+), and the ethereal quality of the whole-tone scale, enriching both your theoretical knowledge and your listening experience.

Keywords:

augmented fifth, music interval, music theory, harmony, dissonance, augmented triad, altered dominant, V+ chord, whole-tone scale, chromaticism, music education, altered chords

Introduction:

In the world of harmony, the perfect fifth is a pillar of stability. It’s strong, consonant, and forms the backbone of the most common chords in Western music. But what happens when we stretch that stability to its breaking point? Enter the augmented fifth: the perfect fifth's mysterious, unsettling, and fascinating sibling. By raising the top note of a perfect fifth by just one semitone, we transform a sense of resolution into a feeling of intense suspense and anticipation. This interval is a key ingredient for composers and songwriters looking to add a touch of ambiguity, drama, or dreaminess to their music.

What Is an Augmented Fifth?

An augmented fifth is a musical interval created by widening a perfect fifth by one chromatic semitone. It spans five staff positions (e.g., C to G) but covers a distance of eight semitones. For instance, the interval from C to G is a perfect fifth (7 semitones). If we raise the G to a G-sharp, the interval C to G-sharp becomes an augmented fifth.

Crucially, while an augmented fifth is enharmonically equivalent to a minor sixth (e.g., C to A-flat), its harmonic function and spelling are entirely different. The augmented fifth's spelling (C-G#) implies a "stretched" perfect fifth, creating powerful tension that pulls upward. In contrast, a minor sixth (C-Ab) is generally a more stable, consonant interval with different melodic tendencies.

Examples in Notation

1. Hearing the Interval

Let's compare a perfect fifth with an augmented fifth. The first measure contains a stable C to G. The second measure raises the G to G-sharp, creating the distinctive, tense sound of the augmented fifth.

2. The Augmented Triad

The most common home for the augmented fifth is the augmented triad. This chord is built with a root, a major third, and an augmented fifth (R - M3 - Aug5) . Its sound is often described as suspended, ambiguous, and restless. Here are C+, F+, and G+ triads.

Practical Applications & Function

The augmented fifth’s primary role is to create harmonic tension that pulls the listener forward. It most often appears in an augmented dominant chord (V+) , which intensifies the need to resolve to the tonic (I). For instance, in the key of C Major, the dominant chord G major (G-B-D) can be altered to G augmented (G-B-D#). That D# creates a strong chromatic pull, resolving up by a semitone to E, the third of the C major tonic chord. This powerful tension-and-release device is used across many genres.

3. The V+ to I Resolution

Listen to how the G+ chord (V+) in the first measure feels "unfinished" and strongly resolves to the stable C major chord (I) in the second measure. Pay attention to the D# moving up to E.

You can hear this exact effect in the opening chords of The Beatles' "Oh! Darling" and in the cinematic tension of many film scores. It's also a staple in jazz harmony, often as part of a more complex altered dominant chord (e.g., G7#5) .

Historical Context & Key Composers

While used sparingly in earlier periods, the augmented fifth became a favorite tool for composers in the Romantic era and beyond.

• Franz Liszt: A pioneer of experimental harmony, Liszt used augmented chords to add virtuosic flair and high drama to his piano works.
• Richard Wagner: Wagner masterfully used augmented harmonies to express intense, unresolved longing, most famously in his opera *Tristan und Isolde*.
• Claude Debussy: In the 20th century, Impressionist composers like Debussy embraced the augmented triad's ambiguous, "floating" quality. As the foundational chord of the whole-tone scale, it allowed him to paint ethereal, shimmering musical landscapes that broke away from traditional tonal gravity.

Fun Fact: The Symmetrical Chord

The augmented triad is perfectly symmetrical! It is built by stacking two major thirds (e.g., C to E is a major third, and E to G# is also a major third). Because of this unique symmetry, any inversion of an augmented triad simply produces another augmented triad. For example, inverting C+ (C-E-G#) gives you E-G#-C, which is an E augmented triad. This property contributes to its "rootless," ambiguous sound and allows it to fit seamlessly into the whole-tone scale, which is itself a symmetrical scale built entirely of whole steps.

Conclusion

The augmented fifth is far more than a theoretical curiosity; it's a powerful expressive tool. As we've seen, this 8-semitone interval transforms stability into suspense, making it essential for building drama, color, and forward momentum. From the potent V+ chord in pop and classical music to the floating soundscapes of Impressionism, the augmented fifth adds a unique and unforgettable flavor. Now that you can identify its sound and function, listen for its distinctive pull in the next piece of music you hear. You might be surprised where it shows up!

References:

1. Piston, W. (1987). Harmony (5th ed.). W. W. Norton & Company.

2. Aldwell, E., & Schachter, C. (2011). Harmony and Voice Leading (4th ed.). Schirmer.

3. Benward, B., & Saker, M. (2015). Music in Theory and Practice (9th ed.). McGraw-Hill Education.