When you think of a microtonal Phrygian music theory masterpiece, Justin Timberlake’s hit “Sexy Back” might not be the first song that comes to mind. However, this seemingly straightforward pop song has some fascinating musical complexities. Let’s dive into what makes this track a unique study in music theory.

Song analysis Sexy Back - Justin Timberlake

Video Tutorial Song Analysis: Sexy Back by Justin Timberlake

If you don’t feel like reading you can check out the video below.

YouTube video
YouTube video for my song analysis on Sexy Back by Justin Timberlake

The Intriguing Elements of “Sexy Back”

“Sexy Back” is a song that challenges conventional tuning. It fuses different musical genres into a unique blend with its detuned relentlessly repetitive two-note synth pattern, loose vocal intonation and monotone kick drum.

The Phrygian Mode With Just Two Chords

At its core, “Sexy Back” is built on a Phrygian chord progression. The Phrygian mode is similar to the natural minor scale, but with one difference: the second scale degree is lowered by a half step. In the case of “Sexy Back,” this lowered second scale degree is the B flat note.

A Phrygian scale in Sexy Back
A Phrygian scale in Sexy Back

The entire song revolves around just two notes: A and B flat. These two notes form the backbone of the track and, in the Tiny Desk Concert version, they are played as power chords on the guitar.

The two note synth pattern in Sexy Back
The two note synth pattern in Sexy Back
The two chord Phrygian chord progression from Sexy Back
The two chord Phrygian chord progression from Sexy Back

Power chords consist of just two notes—the root and the perfect fifth—giving the song a gritty, powerful edge, especially when paired with overdrive or distortion.

A Power Chord
A Power Chord
Modal playbook: exploring the musical modes

Exploring The Musical Modes

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The Out-of-Tune Magic

One of the most interesting things about “Sexy Back” is its tuning. If you try to play along with the original studio version, you might notice that it sounds slightly out of tune. This is because the synth pattern that the entire song is built upon is deliberately detuned.

When you isolate the synth and load it into Melodyne, you’ll notice that the notes don’t sit perfectly on the grid—they’re slightly lower.

Isolated Detuned Synth
Isolated Detuned Synth
Isolated and Tuned synth
Isolated and Tuned synth

The Art of Imperfection

Justin Timberlake’s vocal performance in “Sexy Back” is a masterclass in controlled imperfection. His intonation is loose, and his notes are rarely perfectly on pitch. Yet, this is done intentionally to add character and emotion to the song. A great example of this is in the pre-chorus, where his vibrato rises half a step in pitch, creating a remarkable tension that keeps the listener engaged.

Loose Vocal Intonation during the Pre-chorus
Loose Vocal Intonation during the Pre-chorus

If you were to tune everything perfectly, the vocal performance would lose much of its character and emotional impact. The deliberate detuning of both the synth and vocals is what makes “Sexy Back” so unique and spicy.

Perfectly Tuned Vocals from the Pre-Chorus
Perfectly Tuned Vocals from the Pre-Chorus

Conclusion: A New Perspective on “Sexy Back”

“Sexy Back” might not be the first song you think of when discussing advanced music theory, but it’s a great example of how unconventional elements can come together to create something truly special. From its Phrygian chord progression to its detuned synth and purposefully imperfect vocals, this song is full of musical gems waiting to be discovered.

Whether you’re a fan of Justin Timberlake or simply interested in exploring unique approaches to songwriting, “Sexy Back” offers plenty of inspiration. Next time you listen to the track, pay attention to these details—you might find a new appreciation for this pop classic!