Device Bench

Sound test · Audio out

Left/Right Speaker Test

Start with the volume low, and hold headphones away from your ears for the first press. Press Stop if it is uncomfortable; do not turn up the volume to chase a faint tone.

Channel— Frequency440 Hz Statusidle Web Audio—
Frequency

Verdict, from what you heard

NOT RUN

—

Press Left, say which side you heard it on, then do the same for Right.

How it is decided: the page knows which channel it played and you report where you heard it. Both sides heard where played is PASS. Heard on the opposite side (a swap), on both sides (mono), or not at all on either is CHECK SETTINGS. One side heard correctly while the other plays nothing is LIKELY FAULT in the silent side's path. Details in the methodology.

How this test works

Start with Mid · 440 Hz and press Left, then Right, to compare the two channels. Both plays the tone on both channels at once. Stereo sweep pans one continuous tone from full left to full right over about three seconds, then stops, which makes a weak side easier to notice than two separate presses: a weak side fades as the tone travels toward it, and a dead one drops out. Left, Right and Both keep playing until you press Stop or choose another mode, and the frequency buttons retune a playing tone, so press Stop first if you want a pause between presets. Hearing each tone on the matching side confirms the channel routing all the way from the browser through the operating system to your speakers or headphones.

Browsers only allow audio after you interact with the page, so the Web Audio engine starts on your first channel press. An OscillatorNode makes a sine wave at the selected preset (100 Hz, 440 Hz, or 10 kHz). A GainNode holds its peak at a quarter of digital full scale, about −12 dBFS, and each start and stop uses a gain ramp of roughly 15 milliseconds, because a hard-edged start makes a click you could mistake for a fault. A StereoPannerNode places the tone left or right; browsers without one get two gain paths feeding a two-channel merger instead.

A channel check cannot measure frequency response, distortion, loudness or latency, and a speaker that plays these tones can still sound bad with music. The digital level says nothing about how loud the tone is at your ears. Balance, mono, spatial audio and other sound-effect settings on your system can change how the channels reach you. This is not a hearing test and makes no claims about your ears.

Frequently asked questions

The sound comes out of the wrong side. Is my speaker broken?
Usually not. A swapped result most often means headphones worn backwards, desktop speaker cables in the wrong jacks, or a balance or channel-swap setting in the operating system or headphone software. The browser sends left-channel audio to whatever the operating system treats as the left output, and hardware that swaps its own channels is rare. Check those three things first.
I pressed a button and hear nothing. What should I check?
Keep the volume low while you check the tab's mute setting, the system mute and the output device. The browser plays through the output the system gives it, so the tone may be going to a forgotten Bluetooth headset or an HDMI monitor with no speakers. If the browser was interrupted by a call or another app, press Stop and then a channel button again. The Status readout shows the mode you chose, so it can say playing even when no sound reaches your speakers.
Why is the 10 kHz treble tone so quiet?
Small built-in laptop and phone speakers reproduce very high frequencies weakly and beam them in a narrow direction, so 10 kHz can sound faint, or vanish when you sit off to one side, even when the hardware is fine. Sensitivity to high frequencies also varies a lot from person to person. Do not raise the volume to chase it. Try headphones, or go back to Mid · 440 Hz for the channel comparison.
Does the stereo sweep work on a phone or a mono Bluetooth speaker?
Yes, it plays, but on a single speaker you will not hear it move. A device with one speaker, or a mono Bluetooth speaker, combines both channels into one, so the sweep stays at roughly the same volume in one place, which is normal for that device. To judge stereo separation on a phone, plug in or pair stereo headphones and check that the phone's mono audio setting is off.
Does this test use my microphone or send audio anywhere?
No. The tone is generated inside your browser and goes straight to your output device. The page does not ask for microphone access, records nothing and uploads nothing, and once it has loaded, the tones play without a network connection.

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