Shepard tones are not physically dangerous. They won’t damage your hearing any more than any other sound at the same volume, and they don’t cause seizures or lasting neurological effects. What they can do is make you feel uneasy, tense, or slightly off-balance, especially with prolonged or repeated listening. That psychological discomfort is the whole point of the illusion, and for most people it passes as soon as the sound stops.
How the Illusion Works
A Shepard tone is an auditory illusion made from multiple sine waves spaced an octave apart, all playing simultaneously. As one tone rises in pitch, another fades in at a lower octave to take its place. Your brain blends these overlapping layers and perceives a single tone that seems to climb (or descend) forever without actually getting higher. It’s the audio equivalent of an endless staircase.
Brain imaging studies show that the illusion doesn’t just activate the auditory cortex. It also triggers areas of the visual cortex, suggesting your brain is working harder than usual to make sense of what it’s hearing. The pitch misjudgment isn’t a glitch in the sound itself. It happens because the dominant frequency falls within the range where your hearing is most sensitive, and your brain locks onto that frequency while ignoring the quieter tones cycling in and out.
Why It Feels Unsettling
If listening to a Shepard tone makes you feel anxious or tense, you’re in the majority. In a study published in Frontiers in Psychology, participants listened to Shepard-Risset glissandos (the continuous, sliding version of the tone) and rated their emotional responses on a scale. Across the board, listeners rated negative emotions like tension, anxiety, nervousness, and irritation higher than positive ones like relaxation, joy, or serenity.
The effect was strongest in people who experienced what researchers called a “disturbance of equilibrium,” a feeling of being physically or perceptually thrown off balance. Those participants scored significantly higher on negative emotions compared to people who didn’t feel that disruption. Positive emotions, interestingly, were the same in both groups. The illusion doesn’t suppress good feelings so much as it generates a layer of discomfort on top of whatever else you’re experiencing.
This happens because your brain expects a rising pitch to eventually resolve, to reach a peak or stop climbing. A Shepard tone never delivers that resolution. The constant violation of expectation creates a low-level tension that your nervous system reads as something being wrong, even though nothing actually is.
The Dunkirk Effect
You may have encountered Shepard tones without realizing it. Hans Zimmer built the entire score of Christopher Nolan’s 2017 film Dunkirk around the illusion. Nolan wanted a feeling of relentless, ever-increasing intensity that never lets up, and the Shepard tone delivered exactly that. The film’s soundtrack layers the illusion into orchestral music so that audiences feel mounting dread for nearly two hours straight.
This is the most common real-world use of Shepard tones: as a tool for emotional manipulation in film, video games, and sound design. The tone itself isn’t doing anything harmful to your ears or brain. It’s just very, very good at making you feel like something terrible is about to happen.
Who Might Want to Be Cautious
For most people, a Shepard tone is a brief curiosity, something you listen to for 30 seconds on YouTube, feel vaguely weird about, and move on. But certain groups may find the experience more than mildly uncomfortable.
People with misophonia, a condition involving hypersensitivity and strong emotional reactions to specific sounds, may be more reactive to Shepard tones. Misophonia involves heightened connections between the brain’s auditory processing, emotional regulation, and autonomic nervous system pathways. Exposure to triggering sounds can decrease cognitive control and hijack attention, and individuals with more severe symptoms often experience broader sensory hypersensitivity that extends beyond their specific triggers. A Shepard tone isn’t a classic misophonia trigger (those tend to be everyday sounds like chewing or breathing), but its repetitive, unresolvable quality could provoke a stronger response in someone whose auditory processing is already on high alert.
People with anxiety disorders or sensory processing differences may also find the experience more distressing than average. If you already tend toward sensory overload, an illusion specifically designed to create unresolved tension is worth approaching with some awareness. Turning it off is the only intervention you need.
Hearing Damage and Volume
The one genuinely physical risk with Shepard tones is the same risk that applies to any sound: volume. Because the illusion feels like it’s always rising, some people instinctively turn up the volume trying to “follow” the tone higher, or they listen through headphones at high levels to get the full effect. Prolonged exposure to any sound above about 85 decibels can damage hearing over time, and that applies equally to Shepard tones, music, podcasts, or traffic noise.
At a reasonable listening volume, a Shepard tone poses zero risk to your hearing. The frequencies involved are ordinary sine waves in the normal range of human perception. There’s nothing about the acoustic signal itself that’s different from any other tone your speakers can produce.
The Bottom Line on Safety
A Shepard tone is an auditory illusion, not a weapon. It can make you feel tense, anxious, or slightly dizzy, particularly if you listen for an extended period. Those feelings are a normal response to a sound designed to exploit how your brain processes pitch. They resolve when you stop listening. There is no evidence that Shepard tones cause lasting psychological harm, neurological damage, or physical injury at normal volumes.