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Device test · Audio

Sound Test

Play a test tone through the left speaker, the right speaker, or both, then run a smooth left-to-right sweep to hear stereo separation. The tone is synthesized on your device with the Web Audio API — nothing is downloaded, recorded, or sent anywhere.

Channel— Frequency440 Hz Statusidle Web Audio—

Start with the system volume at a comfortable level. If you are wearing headphones and are not sure how loud it is set, hold them slightly away from your ears for the first press.

Frequency

How this test works

This page checks one narrow thing: whether each stereo channel reaches your ears, and from the correct side. Pressing Left routes a tone only to the left channel of your current output device; Right and Both do the same for their sides. The sweep pans one continuous tone from full left to full right over about three seconds, which makes a weak or dead side easier to notice than two isolated presses. Because the tone is generated on your device, hearing it on the correct side confirms the entire playback path — browser, operating-system mixer, driver, and the speaker or headphone driver itself.

The tones come from the Web Audio API. An OscillatorNode produces a pure sine wave at the selected preset (100 Hz, 440 Hz, or 10 kHz), a GainNode holds the level at a fixed modest value, and a StereoPannerNode places the sound in the stereo field; browsers without a stereo panner get an equivalent two-channel merger. The level never jumps: every start and stop rides a gain ramp of roughly 15 milliseconds, because a hard-edged start produces an audible click that could be mistaken for the very fault you are testing for. Browsers only permit audio after a user gesture, so the audio engine is created on your first button press.

A channel test is deliberately limited. It cannot measure frequency response, distortion, loudness, or latency — a speaker that passes here can still sound bad. If left and right arrive swapped, the cause is almost always outside the hardware: cables in the wrong jacks, a balance or channel-swap setting, or headphones worn backwards. Some output paths also process audio before it reaches the speaker — spatial or enhancement modes can blur hard panning, and mono devices collapse both channels into one. 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?
Almost certainly not. The browser hands left-channel audio to whatever the operating system considers the left output, so a swapped result usually means swapped cables on desktop speakers, a balance or channel-swap setting in the OS or headphone software, or headphones worn backwards. Hardware that swaps its own channels is very rare.
I pressed a button and hear nothing. What should I check?
Confirm the readout says playing — if it does, the tone is being generated and the problem is downstream. Check the system volume and mute state, then check which output device the operating system is using: browsers play through the default device, so the tone may be going to a forgotten Bluetooth headset or an HDMI monitor with no 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 off-axis even when the hardware is fine. Sensitivity to high frequencies also varies a lot from person to person. Try headphones before concluding anything — and note this page is a channel check, not a hearing test.
Does the stereo sweep work on a phone or a mono Bluetooth speaker?
Devices with a single speaker collapse both channels into one, so the sweep plays at roughly constant volume without appearing to move. That is the device summing to mono, not a fault. To actually judge stereo separation on a phone, plug in or pair a set of headphones.
Does this test use my microphone or send audio anywhere?
No. The tone is synthesized inside your browser and routed straight to your output device — output only. The page never asks for microphone permission, records nothing, and transmits nothing; it works the same with the network disconnected.

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