Speaker Test

Play a tone into the left speaker, the right speaker, or both, and confirm each one is working.

Balance and separation

Once you know both speakers work, the next question is whether they are working equally. This sweeps a tone smoothly from left to right, and offers hard left, centre and hard right as fixed points so you can compare a side directly against its opposite.

This plays at -20 dBFS. That is a level below the signal's own full scale, not a measurement of how loud it arrives in your room — the browser has no way to know that, and this page does not claim to.

What a channel test proves, and what it does not

A silent or quiet side tells you that something in the path to that speaker is not delivering signal at the level the other side is. It does not tell you what. The speaker itself could have failed, the cable or connector on that side could be loose or damaged, a balance control somewhere in the chain could be pushed off centre, or an output could simply be switched off or muted. All four produce the same symptom here: one side quieter than the other. This narrows the search to that side of the chain; it does not decide which link in it is at fault. Swapping the suspect speaker to the other output, or trying a different cable, is usually the fastest way to finish the diagnosis this tool starts, and Dead, Blown or Miswired: Diagnosing a Silent Speaker walks through that swap and what to listen for once you have narrowed the fault to one side.

Why a tone, and not a song

A commercial recording is mixed on purpose to put different content on each side — a guitar panned left, backing vocals panned right, reverb tails that are never quite symmetrical. Listen to a piece of music through one speaker at a time and it will sound different on each side even when both speakers are functioning perfectly, because the mix itself is not identical left to right. A single tone removes that variable: the signal sent to each channel is exactly the same, so any difference you hear is a difference in your equipment, not in the source.

Balance controls and accessibility settings

Before you suspect a speaker, check the software. A left/right balance slider, once nudged, quietly favours one side forever until someone finds it again. Windows keeps one per output device: open Settings, go to System, then Sound, choose the device, and look under its volume options for a left/right balance control. It is easy to move by accident with a mouse drag and easy to forget it exists.

Also check for a mono toggle. Windows has a "Turn on Mono Audio" option in its accessibility settings, and macOS has an equivalent "Mono Audio" toggle in Accessibility → Audio; both exist for someone who has full hearing in only one ear, and both deliberately fold both channels down to identical mono content. Left on by mistake, it makes every stereo test on this page report "identical on both sides" — not because your speakers are wired to mono, but because the operating system is doing it for you before the sound ever reaches them.

Testing a pair of earbuds rather than room speakers instead? Why is one earbud quieter than the other covers the iOS and Android versions of this same balance setting, plus the wax-blocked mesh that turns out to cause this far more often than any setting does.

What the centre check actually proves

Play the tone hard left, then hard right, then centred, and pay attention to where the sound in the centre seems to come from. With two working speakers playing an identical, in-phase signal, the ear builds a "phantom" image that sits in the middle, between the speakers, rather than at either one. That fusion only happens when both sides are equal in level and in phase — the same signal arriving at the same time. A balance problem breaks the level half of that; a wiring fault where one speaker's leads are reversed breaks the phase half instead, and produces a different, more distinctive failure that this tool is not built to find. That is the polarity test's job, elsewhere on this site — this one only checks whether the two sides agree on loudness.

Bluetooth speakers and single-driver devices

A Bluetooth speaker, soundbar, or laptop's built-in output frequently reports itself to the operating system as a stereo device while containing only one driver, or two drivers so close together that separation is inaudible. Run this test on one of those and "both sides sound identical" is the correct, expected result — there is no fault to find, because there was never any physical separation to hear in the first place. Genuine stereo separation requires two physically distinct speakers with some distance between them; nothing about how a device names itself to the computer guarantees that it has one.

Where you are sitting matters

This test assumes you are sitting on the centre line between your speakers, equally distant from both. Move off to one side and the nearer speaker will sound louder and arrive sooner, purely from the extra distance the far speaker's sound has to travel — an effect identical to what an actual balance fault would produce, for a reason that has nothing to do with your equipment. If a balance problem shows up here, walk to the midpoint between the speakers, face forward, and run it again before concluding anything is wrong.

Not sure where the problem is? Run the full sound check: six quick questions, and one summary that points you at the right tool.