Stereo / Left-Right Audio Test
Check left/right routing, center image, a finite left-to-right pan sweep, and bounded phase references with locally generated audio you confirm yourself.
- Browser capability-dependent
- No device permission
- Optional history in this browser
- No account or upload
Important
- Results are your listening notes only. Wiring, OS mixers, and Bluetooth profiles can swap channels.
Browser-generated signal gain only, from 0.02 to 0.4. It is not calibrated dB SPL, system volume, amplifier level, or a safe-listening guarantee.
Choose a known stereo reference
Each button starts one finite browser-generated signal. Record only what you perceived for the last signal that started successfully.
Observation for the last successful signal
Play a signal successfully before recording an observation.
- Audio status
- Ready
- Playing
- No
- Last signal
- —
- Signals played
- 0
- Observations
- 0
Recent stereo checks
Up to five self-reported checks are stored in this browser only. Audio is generated locally; no microphone, camera, recording, or upload is used.
No saved stereo checks yet.
How to use
- Select the intended output, lower external volume, and temporarily note any mono, spatial-audio, Bluetooth, HDMI, or receiver processing.
- Play Left, Right, and Both / Center first, then compare Alternating L/R and the finite Left-to-Right pan sweep.
- Play both phase references before recording a phase comparison. Audio never autoplays, and Stop all sounds works at any time.
- Record only what you perceived for each successful signal, then save the check locally if useful.
- Change one routing or processing variable at a time and repeat with a known source when an observation is unclear.
What the result means
- An expected Left or Right observation means the selected browser channel reached the side you reported; it is not hardware certification.
- A shifted center can involve OS balance, mono or spatial processing, placement, the receiver path, the room, the listener, or hardware.
- A reversed or one-sided pan observation is a prompt to check routing and compare another known source, not identification of a failed part.
- Phase comparison is a subjective response to two digital references. It does not diagnose wiring or physical polarity.
Limitations
- The page requests known browser channel positions but cannot verify the physical acoustic image, speaker balance, separation in dB, or amplifier health.
- Mono accessibility, spatial audio, Bluetooth profiles, HDMI, receivers, adapters, placement, and room acoustics can alter what reaches you.
- App output gain is not calibrated dB SPL, system volume, amplifier level, or a safe-listening guarantee.
Troubleshooting
- No sound
- Check system output device, browser mute, and that you clicked a play button after a user gesture.
- Left and Right sound reversed
- Check channel mapping, cable or receiver routing, output-device selection, and compare a known stereo source before changing hardware.
- Both sides play during a one-side signal
- Check mono accessibility, Bluetooth profile, spatial processing, receiver modes, and the selected output path.
- Center is shifted or pan does not move as expected
- Check OS balance, speaker or headphone placement, mono/spatial settings, HDMI or receiver routing, then repeat with one variable changed.
- Phase contrast is unclear
- Confirm both references played, disable optional mono/spatial processing, and repeat at a comfortable level. No clear difference is a valid observation.
Related tools
FAQ
Is audio uploaded?
No. Tones are generated locally with Web Audio and never sent to a server.
Does this certify stereo hardware or speaker wiring?
No. It provides known browser-generated references and stores your observations. It cannot certify hardware, measure channel separation, or diagnose a wiring fault.
What does the pan sweep measure?
It asks the browser to automate a finite pan from full left to full right. Your response records perceived movement; it does not measure balance or pan law.