Channel identity
Left and right use exact digital silence in the unused channel. Guided mode adds a dual-mono center cue.
Stereo imaging diagnostic
Hear the space between left and right
Check channel identity, equal-level alternation, a phantom center, smooth pan movement, and relative phase with short local signals.
Output only · local audio
Web Audio output only. No microphone, camera, MIDI, device list, files, storage, or network requests.
Start with your system volume low
The page starts at 4% digital gain, but your amplifier, headphones, speakers, and system volume determine the actual sound pressure. Stop if anything feels loud or uncomfortable.
How to use
- Sit centered between speakers, or wear headphones in the correct orientation.
- Confirm the safety check; every sound still needs its own click or key press.
- Run the five checks in order and record what you actually hear.
- Repeat odd results on another output before changing cables or settings.
Listening console
The cues are deterministic band-limited noise, not a hearing test or an acoustic measurement. Starting another cue replaces the current one.
Safety confirmation needed
This browser does not expose the Web Audio features needed for controlled stereo output. No sound can be started here.
Now playing
0.0 s
No sound has played.
Unlock the console above, then begin with channel identity.
2% minimum12% maximum
Equal-level alternation
Six matched pulses switch L–R–L–R–L–R. Compare apparent loudness, not tone color.
Phantom center
The same correlated signal reaches both channels at equal gain. It should form a stable center under symmetric listening conditions.
Pan continuity
Use a fixed point or a six-second equal-power sweep. Listen for a clean path without jumps, holes, or a sudden level drop.
Hard leftCenterHard right
Relative phase comparison
A is identical in both channels. B flips only the browser’s right signal. Compare focus and fullness from the same listening position.
Interpret your observations
These notes describe plausible next checks. They do not diagnose a component or your hearing.
No observations yet
Run a cue, then choose the closest description beneath that check.
Nothing is saved; Reset all clears the choices and returns the safe starting level.
What this browser check cannot prove
No hardware verdict
The browser controls a stereo signal before your operating system and playback chain. It cannot inspect a cable, driver, amplifier, Bluetooth path, or physical speaker placement.
No physical-polarity verdict
A/B can reveal an audible relative difference, but it cannot identify which channel is physically reversed—or prove that either one is. Room acoustics and headphones change the result.
No calibrated level or location
The percentage is digital page gain, not dB SPL. Perceived center and pan depend on seat, symmetry, reflections, system processing, ear fit, and individual hearing.