Hidden in Plain Hearing: How Pop's Biggest Hits Are Quietly Borrowing From Music's Most Unsettling Scale

You know that feeling when a song grabs you and you can't quite explain why? Like there's something slightly wrong with it — a tension that never fully resolves, a chord that sits just a little crooked — but instead of turning it off, you turn it up? Chances are you've been on the receiving end of one of pop music's best-kept production secrets: the Locrian sneak.

For centuries, the Locrian mode was essentially the black sheep of Western music theory. Classical composers avoided it like a bad contract. Church musicians refused to touch it. Even modern music educators tend to introduce it with a shrug and a warning. It's the one mode built on a diminished fifth — the tritone, the so-called "devil's interval" — which gives it this restless, unresolved quality that practically begs for a resolution that never quite comes. In a word: uncomfortable.

But discomfort, it turns out, is addictive. And pop producers figured that out a long time ago.

The Tension You Can't Name

Here's the thing about Locrian: you don't have to fully commit to it for it to do its work. Unlike major or minor scales, which create clear emotional landscapes, Locrian is more like a spice than a main ingredient in mainstream contexts. A producer doesn't need to write an entire track in B Locrian to get the effect. They just need to borrow the flavor — a flattened second here, a diminished fifth lurking in the bass line there — and suddenly a song that should feel straightforward starts doing something stranger and more compelling.

Musicologists call this modal borrowing, and it's been a compositional tool for decades. But what's changed in the streaming era is the intentionality behind it. With data-driven production cycles and A/B testing of sonic elements, labels and producers are increasingly aware that a certain quality of unease keeps listeners engaged longer. Unresolved tension triggers a psychological loop. Your brain wants the payoff, keeps waiting for it, and in the meantime, the stream count climbs.

Dr. Rachel Yee, an ethnomusicologist who consults for several mid-size American labels (and who asked that her clients not be named), put it bluntly in a recent conversation: "The most successful pop producers right now are basically applied psychoacousticians. They know exactly which intervals create discomfort and exactly how much discomfort an average listener will tolerate before it becomes pleasurable rather than off-putting. Locrian elements sit right at that edge."

Where You've Actually Heard It

Let's get specific, because this isn't abstract theory.

Billie Eilish's production team — her brother Finneas in particular — has spoken openly about building tracks around wrong-feeling intervals and unresolved harmonic movement. Listen to the verses of "Bad Guy" or "Bury a Friend" with fresh ears. That creeping, slightly nauseating forward momentum isn't just a vibe — it's a structural choice. The bass movement in those tracks borrows heavily from diminished intervals that are foundational to Locrian's character.

Or consider the darker corners of The Weeknd's catalog. Tracks like "Blinding Lights" get the nostalgia headlines, but dig into "Scared to Live" or the more understated cuts off After Hours and you'll find harmonic choices that sit in genuinely uncomfortable modal territory. His producers have layered synth pads and bass lines that create a constant sense of something being slightly out of place — a feeling that maps almost perfectly onto Locrian's flattened second and diminished fifth.

Even Taylor Swift's more experimental work isn't immune. The production on folklore and evermore, handled largely by Aaron Dessner of The National, introduced a level of harmonic ambiguity to her songwriting that longtime fans found disorienting at first and then completely hypnotic. Dessner, who comes from an indie rock background steeped in dissonance, naturally gravitates toward modal tension as a compositional tool. The result was two albums that felt simultaneously like Taylor Swift and like something slightly alien.

The Producer's Playbook

So how does this actually work in a session?

According to producers who work in both experimental and commercial spaces, the process is rarely as calculated as it sounds in retrospect. Most aren't sitting down with a theory textbook and saying, "Okay, let's add some Locrian today." It's more intuitive than that — a sense that a chord change feels too resolved, too comfortable, too expected, and then a deliberate choice to pull it somewhere stranger.

The techniques vary, but a few show up consistently:

Flattening the second in the melody. This is the Locrian move that casual listeners feel most viscerally without recognizing it. When a vocal melody steps down to a flattened second — a half-step below the root — it creates an immediate sense of wrongness that's deeply compelling. It's the musical equivalent of a jump scare, except slower and more sustained.

Leaving the bass on a diminished fifth. Pop production often anchors emotional security in the bass register. When producers deliberately park the bass on an interval that creates dissonance against the chord above it, the whole track starts to feel unstable in a way that keeps ears searching for resolution.

Refusing the tonic resolution. Locrian's most defining characteristic is that its home base never actually feels like home — the diminished fifth built into the tonic chord makes true resolution impossible. Producers who understand this borrow the technique by writing songs that seem to be building toward a satisfying chord change and then sidestepping it, leaving the listener in a perpetual state of pleasant anticipation.

Why American Audiences Are Ready for This

There's a cultural dimension to this shift worth noting. American mainstream music has historically leaned hard into resolution — the chorus payoff, the key change climax, the final triumphant chord. We've been a nation of musical catharsis-seekers. But something has shifted, particularly post-2016, in what listeners seem to want emotionally from their music.

Streaming data consistently shows that songs with ambiguous emotional valence — tracks that feel neither purely happy nor purely sad, but something more complicated — outperform simple emotional monoculture in terms of replay rate and playlist longevity. Listeners, particularly in the 18-34 demographic that dominates streaming, seem to be seeking out music that mirrors the emotional complexity of their actual lives rather than offering clean, uncomplicated resolution.

Locrian, with its built-in refusal to settle, is structurally perfect for that moment.

The Paradox Resolves (Sort Of)

Here's the real twist in all of this: the Locrian mode was considered unlistenable for so long precisely because it doesn't resolve. It doesn't offer the comfort that Western ears were trained to expect. And yet that unresolvability — that persistent, low-grade tension — turns out to be exactly what makes it effective as a pop tool in an era when listeners are emotionally sophisticated enough to find comfort in discomfort.

The scale that scared classical composers isn't hiding in the underground anymore. It's in your workout playlist, your late-night drive soundtrack, the song you've streamed forty-seven times this month without knowing why you can't stop.

You've been listening to the devil's interval all along. You just didn't know you liked it.