Left / Right Audio Test
Play the left, right, or both channels to check headphones or speakers.
Runs in your browser. No microphone, recording, or upload.
Ready — choose a channel to begin
Test level only — not your system volume. Start low.
Frequency
Tone only — not a hearing test.
Automatic test
Plays left, center, then right. Keep the same volume while it runs.
- Left
- Center
- Right
Sweep and results
Play a moving tone, or confirm what you heard after the automatic test.
Stereo Sweep
A single tone moves smoothly from left to center to right. Use it to notice stereo movement, imbalance, or a missing channel — not as a precise acoustic measurement.
How to Test Headphones
Headphones make it easier to isolate left and right channels because each ear cup feeds one ear.
- Put L on your left ear and R on your right ear.
- Play Left — only the left ear cup should produce the test sound.
- Play Right — only the right ear cup should produce the test sound.
- Play Center or Both — you should hear a balanced, centered image.
How to Test Speakers
With speakers, both of your ears naturally hear both speakers. Sit approximately between them and identify which physical speaker is producing the sound — do not expect the tone to reach only one ear.
- Sit roughly in the middle of the stereo pair.
- Select Left and identify which speaker produces the sound.
- Select Right and identify the other speaker.
- If the wrong speaker plays, check cable routing, placement, and system channel settings.
Common Problems
Use these tips after the automatic test or when a quick channel check sounds wrong.
Left and right reversed
Check headphone L/R markings, system routing, cables/adapters, Bluetooth device settings, and software that remaps channels. For speakers, swapped left/right cables or placement can reverse the image.
One side has no sound
Look for loose connections, damaged cables, balance settings, the wrong output device, Bluetooth issues, mono processing, or hardware failure. Compare with another headset if possible.
One side is quieter
System balance, headphone fit, speaker position, room acoustics, and device audio processing all affect perceived level. This page cannot measure acoustic loudness.
Both sides sound the same / no stereo
Mono mode may be on, the device may be mono, some Bluetooth speakers combine channels, or a phone/laptop may have a single speaker.
No sound at all
Check system volume, tab mute, output device selection, connections, then press a test button again in a modern browser.
How This Test Works
Check whether your headphones or speakers are playing the correct left and right channels. This is an output test — different from microphone input testing.
The test tones are generated locally using your browser’s Web Audio API. An oscillator creates a sine tone, a gain node sets a conservative level with short fade-in and fade-out, and a stereo panner routes the signal fully left, fully right, or equally to both channels. Nothing is recorded or uploaded.
Need to check your microphone instead? Try our Mic Test & Playback
Need a steady test pitch or frequency sweep? Open the Online Tone Generator
Privacy
Local browser audio only
Runs in your browser. No microphone access, recording, or audio upload required. The test tones are generated locally using your browser’s audio APIs and stay on this device.
Answers
Frequently asked questions
Stereo channel checks, headphones, speakers, and what the browser can (and cannot) know.
What is a left / right audio test?
A left / right audio test plays tones through specific stereo channels so you can check whether headphones or speakers are routing left and right correctly. It tests audio output, not your microphone.
Does this test need microphone permission?
No. Test tones are generated locally in your browser. The page does not request microphone access, record audio, or upload sound.
Can the browser detect if my speakers are reversed?
No. The browser can send a left or right signal, but without listening through a microphone it cannot know what your physical speakers produced. You confirm what you hear.
What is the difference between Center and Both?
Both play an equal signal on the left and right channels. In this implementation they use the same balanced routing, so they verify dual-channel output rather than two different technical modes.
Why is there no sound?
Check system volume, browser or tab mute, the selected output device, and your headphone or Bluetooth connection. Start at a low test volume, then increase the slider gradually if needed.
Is this a hearing test?
No. Frequency presets only change the test tone. This tool checks stereo output routing. It does not diagnose hearing ability.