Headphone Test (Left/Right & Bass)

Left and right: checking channels and balance

The Left and Right buttons send a plain tone to one channel only. If you hear the Left tone in your right ear, the headphones are on the wrong way round, or the wiring or adapter is swapped. If you hear it in both ears equally, something is mixing the channels together — usually a Mono Audio setting.

The tone in each ear should sound about equally loud. If one side is clearly quieter, check your device's balance slider (usually in Accessibility settings), clean the quieter earbud's mesh and try again. With wired headphones, wiggle the cable near the plug while a tone plays; crackles or drop-outs point to a damaged cable or jack.

Bluetooth earbuds

True wireless earbuds have a separate battery and radio in each bud. If one side doesn't play at all, check that both buds are charged and seated properly in the case, then take them out together. Re-pairing or resetting the earbuds following the maker's instructions often fixes a side that has dropped out.

Bluetooth adds a small delay and compresses the audio, so the sweeps may sound a little less smooth than on wired headphones. That's normal and isn't a fault.

Mono audio and other settings

iPhone and Android both offer a Mono Audio option in Accessibility settings. It's useful if you have hearing loss in one ear or only wear one earbud, but it makes Left and Right sound identical. Turn it off to run a proper channel test, and check any balance slider near it.

What the bass test tells you

The bass sweep rises slowly from 20 Hz to 200 Hz. Over-ear headphones and well-sealed in-ear buds can usually reproduce much of that range, while open or loose-fitting earbuds lose a lot of low end. If the bass seems weak, try a different ear tip size first — a good seal makes a bigger difference to bass than almost anything else.

Listen for buzzing, rattling or distortion as the sweep plays. A clean, steady rumble is good; a rattle at one particular frequency can point to a damaged driver or something loose in the housing.

Frequency range and your hearing

The full-range sweep covers 20 Hz to 20 kHz, roughly the range of young, healthy hearing. Most adults stop hearing the top of the sweep well before 20 kHz, because high-frequency hearing declines naturally with age. If the sweep goes quiet near the end, that's very likely your ears, not your headphones.

This is a sound check, not a hearing test. If you notice a big difference between ears, ringing, or muffled hearing, talk to a doctor or audiologist.

Listen safely

• Always start with the volume low and raise it gradually. Test tones can sound much louder than music at the same setting.
• Very low and very high frequencies can seem quiet while still being loud, so don't keep turning up a tone you can't hear.
• Take the headphones off before changing devices or settings, in case audio jumps to full volume.
• Many phones have headphone volume warnings or limits in their sound settings. They're worth switching on.