How do I check left and right speakers?

Press Left only, then Right only, and compare the side you hear with the channel named on screen. The unused channel contains exact zeros. If the output does not match, check the selected audio device, balance, mono setting and cables. The browser cannot locate a fault after its audio output.

Why does nothing play until I press a button?

The first press builds it: the browser audio engine is created by a playback button. Pressing Stop releases the signal and leaves the engine open and silent for the next press. Leaving the page or closing the tab closes the engine itself. If the browser holds playback for an interaction, the page reports it and asks for another press.

What does the volume number mean?

The control starts at 20% and is capped at 0.35 of digital full scale. The starting gain is 0.07, about -23.1 dBFS. This is a digital signal level, not the sound pressure at your ears: your device volume, amplifier, speakers and distance still matter. Turn down the device volume before starting.

What are the sine tone and pink noise for?

The sine control accepts 20 Hz to 20,000 Hz, subject to the browser sample rate and the output device. Pink noise is filtered broadband noise for listening across a range of frequencies. Both signals loop in the tab; they can help you notice an audible difference but do not measure frequency response, distortion, acoustic loudness or speaker quality.

Can I compare speaker phase or polarity?

Choose Both and compare Same polarity with Opposite polarity. The second setting reverses the right-channel samples while keeping the left-channel samples unchanged. This is a relative stereo listening comparison, not a measurement of electrical polarity at a speaker terminal. Use a stereo output: mono mixing can cancel the opposite-polarity signal, and output processing or room acoustics can change what you hear.

Can I use this on a phone, laptop, headphones or Bluetooth speaker?

Yes, when the browser provides Web Audio and your chosen system audio output can play it. This includes browser playback on iPhone, iPad, Android, Windows, Mac and Linux. The page uses the active media output; it cannot force sound through a phone call earpiece, select a particular driver, or run a device diagnostic code. A single speaker or mono Bluetooth output cannot preserve separate left and right channels.

Does this play surround channels or record the microphone?

It sends a two-channel left/right buffer only. It does not address a center speaker, rear speakers or a subwoofer channel independently, and it never opens a microphone. A system may route or mix that stereo signal into other outputs, but that does not make this a 5.1 channel test.

Can a test tone repair a damaged or wet speaker?

No. This page plays reference signals; it does not remove water, clean a speaker, repair damage or certify that a driver works correctly. An audible buzz, rattle or silence is an observation, not a diagnosis.

Is anything uploaded, and what does this page remember?

Nothing is uploaded or recorded by the test. Its audio is generated in the tab without opening a microphone. Frequency and volume are remembered in this browser when storage is available. Playback, channel, signal and stereo phase are not saved, and a reload opens silent. Copy puts the visible settings summary on your clipboard.

Does this test my hearing?

No. It checks audio output and sends reference signals. It cannot assess your ears or provide a calibrated hearing result.

Speaker Test

Check whether your audio output makes sound and whether its left and right channels match the labels. Nothing plays until you press Left only, Both or Right only. Choose a sine tone or pink noise, or compare matching and opposite stereo polarity with Both. The volume starts at 20% of a capped digital level; your device volume still determines the sound you hear.

Leftready

Rightready

Your device's own volume control still applies. Turn it down before the first press, then raise it until the tone is comfortable.

Signal

Frequency

Volume

20%

Stereo phase, for Both

No pass/fail result is calculated for this listening comparison.

Nothing is playing. Press Left only to send a 440 Hz sine tone to the left channel at 20% of the capped level.

This testsettings only, nothing about you
Speaker test: 440 Hz sine tone, left only, volume 20% (-23.1 dBFS).
Levelvolume times the 0.35 ceiling
20% of the capped level, -23.1 dBFS
Loophow the buffer is built
A whole number of cycles is fitted into the 2 second loop, so the seam cannot click
Sinewhat it is for
one generated frequency for listening to an audio output

Sound on one side onlythe channel is named on screen
Compare Left only and Right only. If one is silent, check the active output and balance, then the cable and speaker. This page cannot distinguish a cable fault from a driver fault.
The sides are swappedwiring, not the browser
Left only names the left channel sent by the browser. If the sound comes from the other side, inspect the output channel assignment and cabling before changing the connection.
Both sides sound identicala mono output cannot be told apart here
A mono setting, a single speaker or an output that mixes the channels can make Left only and Right only sound alike. Separate channel signals do not guarantee separate physical speakers.

Nothing plays until you press a button. The control runs from 0 to 100% of a level capped at 0.35 of full scale, about -9.1 dBFS, and it opens at 20%.

Accuracy. This checks that your speakers make sound and that the left and right channels are the way round you expect. It cannot test your hearing, and it cannot know what happens after the signal leaves the browser: a system equaliser, a mono setting or a Bluetooth speaker that mixes both channels will change what you hear from an unchanged signal.

Common questions

How do I check left and right speakers?: Press Left only, then Right only, and compare the side you hear with the channel named on screen. The unused channel contains exact zeros. If the output does not match, check the selected audio device, balance, mono setting and cables. The browser cannot locate a fault after its audio output.
Why does nothing play until I press a button?: The first press builds it: the browser audio engine is created by a playback button. Pressing Stop releases the signal and leaves the engine open and silent for the next press. Leaving the page or closing the tab closes the engine itself. If the browser holds playback for an interaction, the page reports it and asks for another press.
What does the volume number mean?: The control starts at 20% and is capped at 0.35 of digital full scale. The starting gain is 0.07, about -23.1 dBFS. This is a digital signal level, not the sound pressure at your ears: your device volume, amplifier, speakers and distance still matter. Turn down the device volume before starting.
What are the sine tone and pink noise for?: The sine control accepts 20 Hz to 20,000 Hz, subject to the browser sample rate and the output device. Pink noise is filtered broadband noise for listening across a range of frequencies. Both signals loop in the tab; they can help you notice an audible difference but do not measure frequency response, distortion, acoustic loudness or speaker quality.
Can I compare speaker phase or polarity?: Choose Both and compare Same polarity with Opposite polarity. The second setting reverses the right-channel samples while keeping the left-channel samples unchanged. This is a relative stereo listening comparison, not a measurement of electrical polarity at a speaker terminal. Use a stereo output: mono mixing can cancel the opposite-polarity signal, and output processing or room acoustics can change what you hear.
Can I use this on a phone, laptop, headphones or Bluetooth speaker?: Yes, when the browser provides Web Audio and your chosen system audio output can play it. This includes browser playback on iPhone, iPad, Android, Windows, Mac and Linux. The page uses the active media output; it cannot force sound through a phone call earpiece, select a particular driver, or run a device diagnostic code. A single speaker or mono Bluetooth output cannot preserve separate left and right channels.
Does this play surround channels or record the microphone?: It sends a two-channel left/right buffer only. It does not address a center speaker, rear speakers or a subwoofer channel independently, and it never opens a microphone. A system may route or mix that stereo signal into other outputs, but that does not make this a 5.1 channel test.
Can a test tone repair a damaged or wet speaker?: No. This page plays reference signals; it does not remove water, clean a speaker, repair damage or certify that a driver works correctly. An audible buzz, rattle or silence is an observation, not a diagnosis.
Is anything uploaded, and what does this page remember?: Nothing is uploaded or recorded by the test. Its audio is generated in the tab without opening a microphone. Frequency and volume are remembered in this browser when storage is available. Playback, channel, signal and stereo phase are not saved, and a reload opens silent. Copy puts the visible settings summary on your clipboard.
Does this test my hearing?: No. It checks audio output and sends reference signals. It cannot assess your ears or provide a calibrated hearing result.

This checks that your speakers make sound and that the left and right channels are the way round you expect. It cannot test your hearing, and it cannot know what happens after the signal leaves the browser: a system equaliser, a mono setting or a Bluetooth speaker that mixes both channels will change what you hear from an unchanged signal.