Left Right Audio Test

The test runs blind: the signal goes to the left earcup, the right one, or both in a random order, and the highlight in the picture stays off during the trials. You answer where you heard the sound, and after six trials the page shows the breakdown.

What the breakdown shows

• the channels are swapped: every trial was heard on the wrong side;
• the channels do not separate: the signal went to one earcup, but you heard it in both. This usually means mono mode is on in the system;
• one side stays silent: no trial on that side was heard;
• the channels are in the right places.

What to do with the result

Swapped channels. Look at the earcups first: the L and R marks can be barely visible. If the headphones are on correctly, the sides are swapped in the cable, an adapter, or the system settings.

Sound in both earcups on a one-sided trial. On an iPhone this is "Mono Audio" in the accessibility settings, on Android it is "Mono audio". Less often, the plug is not pushed all the way in.

A silent side. For wired headphones, check the cable right where it meets the earcup: that is where it breaks most often. For wireless ones, disconnect and reconnect them, and charge both earcups.

If you need a full audio breakdown at once — balance, phase, frequency limits, rattle — there is a headphone sound test.