Left Right Speaker Test
Find out instantly whether your left and right speakers or earbuds are wired the right way: play a sound in one channel at a time, sweep it across the stereo field, and check the speaker phase. All sounds are generated in your browser.
Click Left, Center or Right, or run the automatic test.
Speaker phase (polarity) test
Play the same sound in phase and out of phase. With speakers wired correctly, in phase sounds focused in the middle with full bass; out of phase sounds wide, hollow and thin. If it is the other way round, one speaker's + and − wires are swapped.
How to use the Left Right Speaker Test
- Set the volume low first, then put on your headphones or sit between your speakers.
- Click Left: the sound must come only from the left side. Then click Right and Center.
- Run Start left/right test to alternate automatically, with spoken channel names if you like.
- Use Pan sweep to hear the sound travel smoothly from left to right; gaps or jumps point to a balance or wiring problem.
- Check phase with Play in phase and Play out of phase: in phase should sound centered and fuller.
What each test tells you
| Test | Correct result | If it sounds wrong |
|---|---|---|
| Left | Sound only from the left speaker or left ear | Swapped cables or headphones on backwards; heard on both sides = mono mode |
| Right | Sound only from the right | Silent = dead channel, loose plug or balance slider turned fully left |
| Center | A "phantom" sound between the speakers | Pulled to one side = balance setting, unequal speaker distance or a weak driver |
| Pan sweep | Smooth movement from left to right and back | Jumps or a hole in the middle = speakers too far apart or a channel delay |
| Phase | In phase sounds fuller and centered | Out of phase sounds fuller = one speaker has reversed polarity |
Fixing common stereo problems
- Check the balance slider in your operating system's sound settings; it should be in the center.
- Turn off mono audio and "spatial" or surround effects while testing.
- Swap the cables at the amplifier or audio interface: if the problem follows the cable, the cable is at fault; if it stays on the same side, check the speaker or the output.
- Reversed polarity: speaker wire has a marked conductor (stripe, ridge or copper vs. silver). Connect it to + on the amplifier and + on the speaker at both ends.
- Bluetooth earbuds: re-pair them if one bud is silent, and check that each bud's microphone or sensor is not set to mono.
Speaker placement tip
For the best stereo image, sit so that you and the two speakers form an equilateral triangle, with the speakers at the same height as your ears and angled slightly toward you. Keep them at least 30–50 cm away from walls to avoid boomy bass, and check the low end separately with the Tone Generator. If one ear seems weaker no matter what, a Hearing Test can show whether the difference is in your hearing rather than your speakers.
Frequently asked questions
How do I know if my headphones are on the right way?
Click Left. If you hear the sound in your left ear only, the headphones are correct (most are marked L and R inside the band or on the earpieces). If you hear it on the right, turn them around or check the L/R markings.
The left sound plays from both speakers. What's wrong?
Your system is probably sending mono audio. Check for a Mono audio accessibility setting (Windows: Settings > Accessibility > Audio; macOS: Accessibility > Audio; iPhone and Android: Accessibility > Audio), a soundbar or Bluetooth speaker that only plays mono, or a surround upmix effect. The L/R meters in the tool show what the browser sends.
What does the speaker phase test do?
It plays the same sound in both speakers, first identical (in phase), then with the right speaker's waveform inverted (out of phase). Correctly wired speakers sound focused in the center with solid bass in phase, and wide, hollow and thin out of phase. If the out-of-phase version sounds fuller, swap the + and − wires on one speaker.
Why is pink noise the default sound?
Pink noise has equal energy per octave, so it sounds even and is easy to localize. Pure tones can create standing waves in a room, which makes a single speaker sound like it comes from somewhere else. Use the tones if you prefer a clearer, quieter signal.
Can I test surround (5.1 / 7.1) speakers here?
Browsers mix web audio down to stereo for most devices, so this test checks the front left and right channels only. Use your receiver's built-in test tones for center, surround and subwoofer channels, or the Subwoofer Bass Test for low frequencies.
Does the voice announcement come from one side?
No. The browser's speech engine cannot be panned, so the words "left" and "right" play from both speakers as a cue, and the test sound that follows plays in the named channel only.