The Left Channel Plays
Sound comes out of the left earcup, earbud or speaker when only the left channel is sent.
LeftFree online left right tester that checks your audio channels in seconds. Find swapped sides, a silent ear, mono audio and uneven balance, right in your browser.
Send a tone to the left channel, the right channel or both. Pick any pitch and wave shape. Each side should play alone and sound the same.
The left side beeps once, then the right side beeps twice, over and over. You can tell the sides apart with your eyes closed.
The tone jumps from left to right and back. Every hop should land cleanly on one side, with no drop out and no echo on the other side.
Pink noise plays on both sides. Drag the slider until the sound sits right in the middle of your head, or right between your speakers.
A steady tone glides from the left to the right and back. It should move smoothly and pass right through the center, with no jumps or quiet spots.
A low tone plays on both sides with the right side flipped. In real stereo it sounds wide and odd inside your head. If your device mixes to mono, the two sides cancel and the tone almost vanishes.
Five rounds. A tone plays on a random side and the screen does not show which. Pick the side you hear and get a score at the end.
Noise covers every pitch at once, so it is the easiest way to compare the tone and loudness of the two channels. Play Left, then Right.
A left right test sends sound to one audio channel at a time, so you can hear whether each side works and sits on the correct side. A full left right tester also checks for mono audio, uneven balance and a stereo image that moves smoothly from one side to the other.
Sound comes out of the left earcup, earbud or speaker when only the left channel is sent.
LeftThe right side works on its own and is just as clear as the left.
RightLeft audio reaches your left ear, so games, movies and music place sounds where they belong.
Count TestEach side carries its own signal instead of the same mixed copy, which mono audio would cause.
Mono CheckThe sound sits in the middle, without pulling toward one ear or one speaker.
BalanceA tone travels from left to right without jumps, gaps or a dead spot in the middle.
Pan SweepThe whole check takes about two minutes. Follow the steps in order, then go back to the test that matches any problem you hear.
Put the L earbud or earcup on your left ear. For speakers, sit in the middle, facing both.
Choose the right output device and set your volume to about 30% before you press play.
Press Left, then Right, or run Auto Check. Each tone should come from one side only.
One beep should sound on the left and two on the right. The flipped tone should stay loud.
Answer five rounds without looking. A perfect score means your channels are right.
Eight tests in one place work with wired headphones, wireless earbuds, gaming headsets, computer speakers and Bluetooth speakers.
Play the left side, the right side or both, or let Auto Check step through all three. Pick any pitch from 20Hz to 20kHz and four wave shapes, and watch the live level meters show which channel is receiving sound.
One beep on the left and two on the right, so you can tell the sides apart with your eyes closed.
The tone jumps from side to side at the speed you set, to catch a channel that drops out.
Slide pink noise until it sounds centered and see how many decibels one side is off.
A tone glides smoothly between your ears or speakers to check the stereo image.
A flipped tone almost vanishes when stereo is mixed to mono, so mono audio cannot hide.
Five random rounds with the screen hidden give an honest pass or fail score.
Play noise on one side at a time to compare tone and loudness between the channels.
Press L, R, B or Space to test hands free, and let the tone stop on its own after a set time.
Match what you heard to a row below. Each one gives the most likely cause and the first thing to try.
A loose plug, a damaged cable, the balance pushed left or a dead right driver.
Push the plug in fully, center the balance and test another pair to see if the fault moves.
A loose plug, a damaged cable, the balance pushed right or a dead left driver.
Push the plug in fully, center the balance and test another pair to see if the fault moves.
Earbuds on the wrong ears, speakers swapped or a channel swap setting in audio software.
Check the L and R marks, swap the speakers and reset any audio enhancement or swap option.
Mono audio is on, or a single speaker that always plays in mono.
Turn off mono audio in your accessibility settings and run the Mono Check again.
Your device mixes both channels together before it plays them.
Turn off mono audio. On Bluetooth, choose the stereo output, not the headset or hands-free one.
The headset (hands-free) mode is active because an app is using the mic.
Close the call app or pick the stereo headphones output in your sound settings.
A balance offset, dirt in the earbud mesh or a worn driver.
Run the Balance Finder, center the balance and gently clean the mesh with a dry brush.
A broken wire near the plug or where the cable meets the earcup.
Try a spare cable if it is removable. If not, the headphones need repair or replacing.
You heard the opposite side almost every time, so the channels are swapped.
Follow the fix for swapped sides above, then take the quiz again.
Most left and right problems come from a setting, not broken gear. Here is where to look on each device.
It is quick, free and private, and it works with the headphones and speakers you already own.
Every tone is made in your browser. Nothing is uploaded or recorded.
Open the page and test, with nothing to install and no account.
Every test is free, with no limit on how often you use it.
Wired, wireless, earbuds, gaming headsets, computer and Bluetooth speakers.
Runs in any current browser on Windows, Mac, iPhone, Android and Chromebook.
Your answers turn into a clear next step instead of jargon.
Short answers to what people ask most when they check their left and right audio.
Put on your headphones or sit between your speakers, set the volume to about 30% and press Left, then Right, in the left right test above. Each tone should come from one side only. Then run the Count Test and the Mono Check to confirm the result.
When you press Left, the sound should come only from your left ear or left speaker. In the Count Test you should hear one beep on the left and two beeps on the right. A score of 5 out of 5 in the Blind Quiz also means your channels are correct.
The most common reasons are headphones worn backwards, earbuds in the wrong ears, speakers placed on the wrong sides or a channel swap option in audio software. Check the L and R marks first, then swap the speakers or cables.
Usually it is a plug that is not pushed in fully, a damaged cable, the balance slider pushed to one side or a dead driver. Test another pair of headphones. If the same side is silent on every pair, the problem is the device or port.
On Windows go to Settings, Accessibility, Audio. On a Mac go to System Settings, Accessibility, Audio. On iPhone go to Settings, Accessibility, Audio and Visual. On Android open Settings, Accessibility and look for Audio adjustment. Switch mono audio off in each one.
Open your sound settings and center the balance slider, or set the left and right channel levels to the same number. Then run the Balance Finder above. If one side still needs more volume, clean the earbud mesh or check the driver.
Yes. Connect the earbuds, choose them as your sound output and run the test. If both buds play every tone, mono audio is on or the earbuds are in headset mode because an app is using the mic.
Most earbuds and headphones have a small L and R printed on the stem, the inside of the band or the earcup. Some use a raised dot on the left side. Play the Left tone and the bud that sounds is your left one.
Yes. Sit in the middle, facing both speakers, and press Left and Right. The tone should come from the speaker on that side. For a deeper check of bass, rattles and wiring, use the Speaker Test.
The Mono Check flips the right side so the two channels are opposites. In real stereo that sounds wide and strange inside your head. When a device mixes both sides into mono, the opposites cancel out and the tone nearly vanishes, which tells you mono audio is on.
The quiz plays a tone on a random side five times while the screen stays hidden. A score of 5 means your channels are correct. A score of 0 or 1 means you heard the opposite side almost every time, so your channels are swapped.
Yes. It runs in any current browser on iPhone, Android, Windows, Mac and Chromebook. Phone speakers sit close together, so the test is clearest with headphones or earbuds.
Test speakers, your microphone, your hearing and more, all free and all in your browser.
Real problems from listeners, answered and checked by the Sound Tester Audio Team.
No discussions about this tool yet. Start the first one and the team will answer it for free.