Speaker Test
A speaker test has two questions to answer: does each speaker make sound, and is the left one actually on the left. This page answers them with a signal you start yourself. Nothing plays until you press Left only, Both or Right only. The volume control opens at 20% of a level that is itself capped at 0.35 of full scale, so a first press leaves the browser at 0.07 of full scale, about 23 decibels down, and a machine somebody left at maximum does not fill the room. The channel that is playing is named in words on the stage and the silent side is named too, because a lit panel on its own is the half of the answer a crossed cable already looks like. The signal is built here in the tab: a sine tone anywhere from 20 Hz to 20,000 Hz, whose looped buffer is cut to a whole number of cycles so the seam cannot click, or pink noise, which carries every frequency at once and finds a rattle or a dead tweeter faster than one tone can. A left-only test writes exact zeros into the right channel rather than a low level, which is the difference between a silent speaker and a half-seated plug. Nothing is uploaded, there is no account, and the only things kept between visits are the frequency and the volume.
Your device's own volume control still applies. Turn it down before the first press, then raise it until the tone is comfortable.
Nothing is playing. Press Left only to send a 440 Hz sine tone to the left channel at 20% of the capped level.
- Speaker test: 440 Hz sine tone, left only, volume 20% (-23.1 dBFS).
- 20% of the capped level, -23.1 dBFS
- A whole number of cycles is fitted into the 2 second loop, so the seam cannot click
- one frequency and nothing else: the cleanest way to hear whether a driver is working at all
- Press Left only and Right only in turn. If the panel says playing and you hear nothing, the fault is on that side: check the cable, the balance control and the speaker itself.
- Left only should come from your left. If it does not, swap the two speaker cables or the balance setting; the signal leaving this page is the one the panel names.
- A mono setting, a single speaker or a Bluetooth speaker that mixes the channels will play Left only and Right only the same way. That is the system doing it, not this page.
Common questions
- How do I tell whether my left and right speakers are swapped?
- Press Left only and notice which side of the room the sound comes from, then press Right only and do the same. The stage names the channel that is playing and the one that is silent, so there is never a guess about what was sent. What leaves this page is unambiguous: a left-only test writes the signal into the left channel of a two-channel buffer and exact zeros into the right, so anything you hear on the right is happening after the signal leaves the browser. If Left only comes out of the right speaker, the swap is in the cables, in a balance control or in the output settings, and switching the two speaker leads is usually the whole fix.
- Why does nothing play until I press a button?
- Because a page that starts making noise on load is how a quiet office becomes a loud one, and it is the reason people arrive at these pages with the volume already turned down. The audio engine is not created when the page opens or when you scroll past it: the first press builds it, pressing Stop releases the signal and leaves the engine open and silent for the next press, and leaving the page or closing the tab closes the engine itself. Browsers have their own version of the same rule and hold all audio until you interact with the page. When that happens here it is reported in a line of text rather than left as silence you have to explain to yourself, and a second press allows it.
- One side is silent. What should I check?
- Work outwards from the page. First confirm the panel says playing for the side you are testing, because the test only tells you something when the signal was actually sent. Then check the balance control in your system sound settings, which is the most common cause and the least obvious, since it survives a reboot and affects every app at once. Then the physical path: a headphone or speaker plug pushed only halfway in gives exactly this symptom, as does a damaged cable near the connector. Then try the same speaker on another device or another app. If the silence follows the speaker, it is the speaker; if it stays with the computer, it is the setting or the socket.
- Does this test my hearing?
- No, and it is worth being plain about it because several pages that look like this one blur the line. What this page checks is that your speakers make sound and that the two channels are the way round you expect. It cannot know what your ears do with what arrives, and it cannot see what happens to the signal after it leaves the browser: a system equaliser, a mono setting or a Bluetooth speaker that mixes both channels will all change what you hear while the signal itself is unchanged. If you are worried about your ears, that is a question for a professional with calibrated equipment, not for a web page playing through unknown speakers.
- What is pink noise for, and how is it different from the tone?
- A sine tone is one frequency and nothing else, which is the cleanest way to hear whether a driver works at all and to find the point where a speaker stops responding. Pink noise is every frequency at once, weighted so each octave carries the same energy, which is roughly how music is spread and why it is the standard signal for finding a rattle, a buzzing panel, a blocked port or a tweeter that has died while the rest of the speaker still plays. The noise here is generated in the tab, crossfaded at the loop seam so it does not click on repeat, and normalised to a peak of one so it tests at the same peak level as the tone rather than arriving quieter.
- Is anything uploaded, and what does this page remember?
- Nothing is uploaded and nothing is recorded. The signal is arithmetic performed in this tab, written into a two-channel buffer and played through your browser's own audio engine, so there is no request of any kind and no microphone is ever opened. Two settings are kept in this browser between visits, the frequency and the volume, under a single key. What is never kept is any instruction to play: a reload always opens silent, whatever was playing when you left. The Start over button at the top of the page forgets the two settings, and the Copy button puts one line describing the current settings on your clipboard for pasting into a support ticket.
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.