Stereo Test – Left Right Channel, LEDR & Stereo Image Check
Channels and imageReady
- Each side plays alone
- Centre is a solid point
- Wide test sounding focused = check wiring
- Start quiet, raise slowly
- Check L/R markings first
- Disable audio enhancements
- Runs inside your browser
- No upload, no account
- Nothing saved after you close
Stereo sound test for channels, panning and imaging
Stereo playback needs two channels that are in the right place, at the same level and in step with each other. These signals check all three.
Left right channel identification
Tone and noise versions are provided because some faults only show with one of them: a tone reveals level differences, noise reveals tonal differences between the two sides.
Stereo panning and LEDR-style movement
The listening-environment test popularised by studio engineers moves a signal left, up and right to reveal how the room and speakers place sound.
Stereophonic perception and the phantom centre
Stereo works because two speakers playing the same signal create a phantom image between them.
How to Use the
Stereo Test
- 01
Seat
sit centred and equally far from both speakers, or put headphones on the right way round.
- 02
Channels
play Left, Centre and Right with tone and with noise.
- 03
Movement
play both pans and the arc sweep; the sound should glide evenly with no jumps.
- 04
Phase
play the wide test; it should sound vague and spread compared with the centre.
Left right channel identification
Tone and noise versions are provided because some faults only show with one of them: a tone reveals level differences, noise reveals tonal differences between the two sides.
Stereo panning and LEDR-style movement
The listening-environment test popularised by studio engineers moves a signal left, up and right to reveal how the room and speakers place sound. In a browser we cannot place sound vertically, but the arc sweep and pans show whether the image moves smoothly or jumps, which exposes reflections and uneven speaker placement.
Stereophonic perception and the phantom centre
Stereo works because two speakers playing the same signal create a phantom image between them. If you sit off-centre the image collapses towards the nearer speaker, a result of the precedence effect. Moving your chair by 20 cm is often enough to hear this.
Fixing an uneven stereo image
Check the balance slider in Windows (Sound → device → Properties → Levels → Balance) or macOS (Sound → Output → Balance), then speaker distance, toe-in and nearby reflective surfaces. A mono setting under accessibility options will also make every test sound centred.
Related guides and fixes
Learn more in these guides: No sound on Windows, No sound on Mac, Headphones only one side, Speakers crackling, How to test speakers, How to test headphones.
How stereo perception works
Level difference
A sound louder in one ear seems to come from that side; a 15–20 dB difference places it fully left or right.
Timing difference
Arrival time differences under 1 ms also move the image; this is how we locate low sounds.
Timing with low-pass filtering
When high frequencies are removed, timing cues dominate, which is why bass is hard to locate.
Check the route before judging
Confirm left really goes to left before comparing tonal quality.
Test signal notes
Mono source placed in stereo
Our signals start as a single mono source panned between channels.
The real thing
Real music combines level and timing cues; finish with a well-recorded stereo track.
Left right audio test on Windows laptops and Android phones
Windows laptop
- Plug in your earphones or headphones fully.
- Click the speaker icon on the taskbar and choose them as the output.
- Press Left, then Right on this page. Each sound must come from its own side only.
- If both sides sound the same, open Settings → System → Sound → your device and check that Mono audio is off and the left and right levels match.
Android phone
- Connect wired earphones or pair Bluetooth earbuds.
- Open this page in Chrome and press Left, then Right.
- If one side is quiet or both sound the same, go to Settings → Accessibility → Audio (the name differs by brand: Samsung, Xiaomi, Realme, Vivo, Oppo) and check Mono audio and the left/right balance slider.
Frequently Asked Questions
Q.Why do Left and Right both play in the middle?
Mono audio is enabled in accessibility settings, or the device has a single speaker.
Q.What is the wide test for?
It plays the right channel inverted. Normal stereo turns this into a diffuse, hard-to-place sound, so it is a quick wiring check.
Q.Does this test work with Bluetooth?
Yes, as long as the device is in its stereo media profile rather than the hands-free mode.