Headphone and speaker test

The Left and Right buttons play the test sound in one channel only. You should hear it in that ear and nothing in the other. If you hear it in both, your system may be set to mono audio or an adapter is combining the channels. If left and right are swapped, the headphones are on backwards or a cable is reversed.

Both (center) plays the same sound in both channels. It should seem to come from the middle of your head. If it pulls to one side, the two sides have different volume: check the balance setting (see the troubleshooting section below), clean the earbuds, or suspect a weak driver on one side.

The phase test plays the same sound in both channels but flips the right channel upside down (opposite polarity). Instead of a solid center image, the sound should feel diffuse, spread out or as if it were outside your head.

If the normal center test sounds diffuse in the same way, one of your speakers or earpieces is wired with reversed polarity. With desktop speakers, that usually means the red and black wires are swapped on one speaker. Reversed polarity weakens bass and makes the stereo image vague, so it is worth fixing.

The sweep glides from 20 Hz to 20 kHz over 12 seconds. Notice when the deep rumble becomes audible at the start and when the high whine disappears at the end. Two things limit what you hear:

• The equipment. Small laptop and phone speakers usually can't reproduce deep bass; many earbuds and Bluetooth codecs roll off the very top.
• Your hearing. The upper limit of human hearing is often quoted as 20 kHz for young people, and it drops with age.

To measure your own upper limit more precisely, or to test each ear at several frequencies, use the hearing test.

• Sine tone: a pure tone at 100 Hz, 250 Hz, 440 Hz, 1 kHz, 4 kHz or 10 kHz. Good for checking a specific frequency and for spotting rattles or buzzing.
• Noise: pink noise covers the whole spectrum, which makes channel position easy to judge.
• Pulsed noise: noise switched on and off in a speech-like rhythm, easy to locate.

The volume slider here controls the test sound only. Start low and raise it gradually; pure tones at high volume are unpleasant and can harm your hearing.

The built-in troubleshooter under the test detects your system and shows matching steps. The most common causes:

• Mono audio is on (sound in both ears when you click Left). Windows 11: Settings › Accessibility › Audio › Mono audio. Mac: System Settings › Accessibility › Audio, Play stereo audio as mono. iPhone: Settings › Accessibility › Audio & Visual › Mono Audio. Android: look under Settings › Accessibility for Mono audio.
• Balance is off (center pulls to one side). Windows 11: Settings › System › Sound, select the device and adjust the left and right channel volume. Mac: System Settings › Sound › Output › Balance. iPhone: the Balance slider in Audio & Visual. Android: Audio balance in the Accessibility settings.
• Bluetooth sounds flat or muffled: many headsets switch to a low-quality headset (hands-free) profile when the microphone is active. On Windows, choose the stereo headphones entry as output rather than the headset one, or use a separate microphone.
• Sound only on one side or crackling: try another device. If it persists, the cable, plug or a driver is damaged; wiggle the plug gently during a tone to find a weak spot, and check earbud mesh for wax.

For surround systems, the browser outputs stereo only, so this checks the front left and right channels. Need to check the microphone too? Use the mic test.

The same tests work for desktop speakers, soundbars and car audio connected to your phone. Sit in the middle between the speakers, then run the left, right and phase tests. Everything runs in your browser using the Web Audio API; no audio files are downloaded and nothing is uploaded.