Sound Localization Test

What it measures

This test checks your spatial hearing — how well you can tell which direction a sound comes from. Specifically it screens your ability to localize short bursts of noise to the left or right ear, the most basic form of sound localization and one that depends on both ears working together.

How it works

Your brain works out where a sound is by comparing the signal arriving at your two ears. A sound off to one side reaches the nearer ear very slightly sooner (the interaural time difference, or ITD) and a touch louder, because your head shadows the far ear (the interaural level difference, or ILD). This pair of cues is the classic 'duplex theory' of localization first described by Lord Rayleigh. In this test you wear stereo headphones and hear a brief burst of white noise positioned to the left or right using both cues at once: a roughly 0.4–0.6 millisecond delay to the far ear and a 6–10 dB level boost to the near ear. You simply choose which side it came from across fourteen trials. With two options, pure guessing scores about 50%, so the result is compared against that chance level to see whether you are reliably hearing the difference.

Tips for an accurate result

• 1Trust your first impression — Localization is fast and largely automatic. Go with the side your ear leans toward rather than over-thinking each burst.
• 2Check your channel balance first — If your device's left/right balance is set off-centre, or one earbud is quieter, results will skew to one side. Reset balance to centre and make sure both sides sound equally loud before starting.
• 3Notice a one-sided pattern — If you consistently miss bursts toward one particular side, swap your earbuds over and retry. If the bias follows the same ear rather than the headphone, that ear may be worth getting checked.