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Surround Sound 5.1 / 7.1 Channel Test

Play each surround channel in turn — after checking your output can actually carry them.

Reading the output device…

How this test works

Before anything is played, the output device's maximum channel count is read. If it is two, the tool stops and says so, because everything after that point would be a lie: a browser accepts a six-channel graph on a stereo device without complaint and the operating system quietly downmixes it, so every channel comes out of both speakers and every channel appears to work. Where the device genuinely reports six or eight channels, a tone is routed to one channel at a time through a channel merger and you confirm whether it came from the right place. Position matters more than presence — a silent channel is obvious in ordinary use, while two channels swapped sounds completely fine on music and only reveals itself when something moves across the screen.

What the results mean

Output channels
What the device declares. Two means there is no surround layout to test, whatever is plugged in.
Layout
Interpreted from the channel count: six is 5.1, eight is 7.1.
Wrong or silent
The two faults this can find. Wrong position is the more common and the harder to notice.
Subwoofer (LFE)
Non-directional by design, so you may feel it rather than locate it. That is correct behaviour, not a fault.

Common problems and fixes

It says my output is stereo but I have a 5.1 system
The operating system is not configured for it. On Windows the speaker configuration in Sound settings defaults to stereo; over HDMI the receiver also has to be in a multichannel mode rather than passthrough.
Front left and front right seem swapped
Almost always physical wiring or the layout configured in the OS rather than a fault. This is the error people live with for years, because stereo music sounds fine either way.
The centre channel is silent
Check the receiver is not in a stereo or direct mode, which bypasses centre and surround entirely. Then check the speaker is connected and enabled in the OS layout.

Frequently asked questions

Why does the test refuse to run on my laptop?

Because the output is stereo, and any surround test on a stereo output is meaningless — the operating system folds every channel into two speakers, so all of them appear to work. Reporting a pass there would be the bug.

Can a browser really address surround channels?

Where the output device supports it, yes — Web Audio can set an explicit channel count and route discrete channels through a merger. What it cannot do is create channels that the output device does not have.

Why is the subwoofer test a low tone?

Because the LFE channel only carries low frequencies. A midrange tone routed there would either be filtered out entirely or reproduced badly, and neither would tell you whether the channel works.

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