Audio Illusions – Shepard Tone, Phantom Tones & Brown Note Myth
Fool your earsReady
- Start quiet, raise slowly
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Auditory illusions you can play in your browser
Your brain interprets sound rather than recording it. These demonstrations show where that interpretation can be fooled.
The Shepard tone
Several tones an octave apart rise together while the top fades out and a new bottom fades in.
Missing fundamental
Play harmonics of 200 Hz without 200 Hz itself and you still hear a 200 Hz pitch.
The brown note
The idea that a very low tone can make people lose bowel control is popular online, but controlled tests with high-power infrasound have not produced the effect.
How to Use the
Audio Illusions
- 01
Headphones
use them for the octave and binaural demos.
- 02
Shepard
play it for at least 20 seconds and notice it never gets higher overall.
- 03
Missing fundamental
compare the harmonic stack with the reference tone.
- 04
Reflect
read the explanation for each effect below.
The Shepard tone
Several tones an octave apart rise together while the top fades out and a new bottom fades in. Your brain follows the rising motion and never notices the reset, producing a staircase that seems to climb forever. Film composers use it to build tension.
Missing fundamental
Play harmonics of 200 Hz without 200 Hz itself and you still hear a 200 Hz pitch. This is why small phone speakers can suggest bass notes they cannot actually play.
The brown note
The idea that a very low tone can make people lose bowel control is popular online, but controlled tests with high-power infrasound have not produced the effect. It is a myth, and no browser tone will do it.
Why illusions matter for testing
Knowing how hearing can be fooled helps you interpret tests honestly: a bass you “hear” on a small speaker may be the missing-fundamental effect, not real low-frequency output.
Related signals
Other signal categories
Sweeps, noise, impulse and test files are on their own pages.
Related guides and fixes
Learn more in these guides: No sound on Windows, No sound on Mac, Headphones only one side, Speakers crackling, How to test speakers, How to test headphones.
Frequently Asked Questions
Q.Why does the Shepard tone never stop rising?
The loudness of each component follows a fixed bell curve, hiding where it restarts.
Q.Do I need headphones?
For the octave and binaural demos, yes.
Q.Is the brown note real?
No reliable evidence supports it.