Sound reaches you faster than light does
This is the most reliable surprise in reaction testing: people respond to a sound faster than to a light, usually by 30 to 50 milliseconds. It has been measured repeatedly since the nineteenth century and it holds across age groups and experience levels.
The reason is not the speed of sound versus the speed of light — over a metre of air that difference is three milliseconds and irrelevant. It is the processing path. Sound is converted to nerve signals in the cochlea and reaches the auditory cortex in around 8 to 10 ms. Light has to be converted by photoreceptors in the retina, a chemical process, and the visual cortex takes something closer to 20 to 40 ms to register it. The head start is built into the hardware.
So if your audio score here is faster than your visual score on the main test, nothing is broken. That is the expected result. If they are the same, check your volume and whether your headphones are adding buffering latency.
Bluetooth will ruin this test
Wireless audio adds a delay between the browser asking for a tone and your ear receiving it. Standard Bluetooth codecs add somewhere between 100 and 250 ms; low-latency codecs cut that but never to zero. That delay lands entirely inside your measured reaction time, and there is no way for a web page to detect or subtract it.
Use wired headphones or your device speakers for this mode. If your only option is Bluetooth, the score still works for comparing you against yourself on the same headphones — it just cannot be compared against anyone else.
Every mode on this site corrects for display refresh, but no browser can measure your audio output latency. On this page, a wired connection is the correction.
Where auditory reaction time matters
- Sprint starts. Track athletes react to the gun, not to a light, and a start under 100 ms is ruled a false start because it is considered physiologically impossible.
- Competitive gaming. Footstep audio often gives away an opponent before the model appears on screen, which is why serious players treat audio as an information channel rather than atmosphere.
- Driving. A horn, a siren or a skid reaches you before you have found the source with your eyes.
- Music. Playing in time with other people is continuous auditory reaction, which is one reason trained musicians tend to test well on this mode.
How to read your audio score
Compare it against your own visual result rather than against a table. Run the visual test, run this one, and look at the gap. A 30 to 50 ms advantage for audio is the textbook pattern. A much bigger gap usually means your visual run caught you unfocused. A reversed result — visual faster than audio — almost always means output latency in your headphones rather than anything about you.