Press Left or Right. You should hear the sound on that side only.
Headphones: put the L side on your left ear. Speakers: sit in the middle, in front of them. If Left plays on the right, the cables or the headphones are swapped.
About the speaker test
Are your headphones on the right way round? Is one earbud broken? Are the speaker cables swapped? This test answers it in a few seconds.
Press Left, and the sound plays only on the left side. Press Right, and it plays only on the right. Press Both, and it should sound like it comes from the middle, between your ears or between the speakers.
How to use it
- Put on your headphones, or sit in front of your speakers
- Press Left — you should hear it on the left only
- Press Right — you should hear it on the right only
- Press Both — it should sound like it is in the middle
- Or press Left, then right — again and again and just listen
What the result means
- Left plays on the right, and right on the left — the headphones are on backwards, or the speaker cables (or the L/R plugs) are swapped
- One side is silent — that earbud, speaker or cable is broken, or the sound balance in your computer's settings is turned all the way to one side
- One side is quieter — check the balance setting, clean the earbud, or try another cable
- Both buttons sound the same — your sound output is mono (one channel), or a "mono audio" accessibility setting is turned on
- Both does not sound centred — one side is louder than the other
The three sounds
- Beeps — short and clear on any speaker
- Soft noise — a gentle "shhh". The ear can tell where noise comes from much better than where a pure tone comes from, so this is the easiest to place.
- Low bass tone — an 80 Hz hum. Use it to check a subwoofer, or the bass speaker in a stereo. Small laptop and phone speakers often cannot play it at all.
Frequently asked questions
Why do I hear both sides when I press Left?
With speakers, sound from one speaker reaches both ears — that is normal. Listen to *where* the sound comes from, not whether one ear hears it. With headphones you should hear one side only. If not, check that "mono audio" is turned off in your phone or computer's accessibility settings.
How do I fix swapped left and right?
Turn the headphones round, or swap the left and right speaker cables. On a computer, also check that the sound balance is in the middle.
Does it work with Bluetooth earbuds?
Yes. The sound goes to whatever your device is playing to. Bluetooth can add a short delay, so the sound may start a moment after you press the button.
Does it work on a phone?
Yes, in any modern browser. On an iPhone, turn off silent mode first.
Good to know
- The sound is sent to exactly one channel — not "mostly left" — so a correct setup gives a clear answer
- Your sound and volume choices are remembered in this browser
- Nothing is recorded and nothing is sent anywhere
Related tools
- Tone Generator — any frequency from 20 Hz to 20 kHz
- Microphone Test — check your microphone
- Webcam Test — check your camera
- Keyboard Test — find dead keys
- Mouse Test — check every mouse button
