Test your stereo audio setup. Check left and right channels and balance in your browser. Works with speakers and headphones.
Quick stereo routing checker for left-right channels, stereo phase, audio balance, and separation.
Run a stereo test in your browser to verify left and right channel routing and stereo balance.
Follow a left-to-right stereo pan sweep to check whether level changes feel smooth and centered.
The marker should travel smoothly from left to right while the sound pans the same way.
Play left-only, right-only, and both-channel tones to confirm basic stereo routing.
Follow a left-to-right stereo pan sweep to check whether level changes feel smooth and centered.
Run the swap check first. If the left prompt comes from the right side, your audio chain is reversed somewhere.
Use the basic channel test to make sure each side can play on its own and both channels work together.
Finish with the phase comparison, balance sweep, and separation check to catch subtler stereo image issues.
Use stereo test together with adjacent audio tools when you want to isolate routing, bass, speaker, or headphone issues more precisely.
This stereo test helps users confirm that left and right channels are routed correctly, not swapped, and not collapsing into mono. It also checks whether phase behavior sounds normal, whether stereo balance feels even, and whether the two channels remain distinct enough to hear separation clearly. These are common problems with speakers, headphones, car stereos, TVs, gaming setups, and new desktop audio chains. A practical stereo sound test needs several short checks instead of one generic playback button, because routing, phase, balance, and separation can all fail in different ways. That is why this page combines multiple quick audio checks inside one browser-based stereo tester.
Start with the swap check first. If the left prompt reaches the right ear or speaker, your channels are reversed somewhere in the chain. Then run the left-only, right-only, and both-channel playback test to confirm baseline stereo routing. After that, compare in-phase and out-of-phase playback. In-phase should sound more centered and solid, while out-of-phase often feels wider, weaker, or strangely hollow. Next, run the balance sweep and listen for a smooth left-to-right movement without sudden jumps or dead zones. Finish with the stereo separation test, where each side carries different content so you can hear whether the stereo image stays distinct instead of blurring into the middle.
Stereo issues are not always obvious. Left and right channels can be swapped while still sounding mostly fine until a game, movie, or positioning cue makes the mistake clear. Phase problems can make sound feel weak, hollow, or oddly wide without users knowing why. Stereo balance issues can be subtle enough that people blame the track or video instead of the playback chain. Separation can also degrade when software folds sound toward mono, when a cable is faulty, or when hardware processing changes the stereo image. A proper left right stereo test is useful because these issues can hide in normal everyday listening.
This page is useful for people checking speakers, headphones, computer audio, car stereo systems, gaming headsets, TVs, audio interfaces, receivers, and freshly connected desktop speakers. It helps after changing cables, replacing an adapter, updating audio software, moving speakers, or troubleshooting why stereo sound feels wrong. It also works well as a fast first check before running more specific tools like speaker test, headphone test, or bass test. If you only need to know whether stereo is actually working correctly, this tool is often the fastest path.
If the channels are swapped, check operating system balance settings, cable routing, USB audio adapters, AV receivers, Bluetooth device configuration, and any virtual audio software. If in-phase and out-of-phase playback sound too similar, one speaker or channel may have reversed polarity. If the balance sweep jumps or leans to one side, inspect speaker placement, earcup seal, mixer balance, and accessibility audio settings. If separation feels weak, make sure your device is not forcing mono audio and that no enhancement layer is collapsing the stereo image. Browser audio tests are best for diagnosis, but the actual fix is usually somewhere in hardware routing or system configuration.
A stereo test checks whether left and right audio channels are routed correctly, balanced properly, and staying distinct instead of collapsing into mono.
A proper stereo test plays left-only audio and right-only audio separately so you can verify that each side is reaching the correct speaker or ear.
An out-of-phase stereo test inverts one channel so you can compare the sound against normal in-phase playback and spot polarity-related problems.
Yes. Stereo routing, phase, and balance checks are useful for both headphones and speakers, as long as your browser and device can play stereo audio normally.
If every mode sounds centered, your system may be forcing mono audio, downmixing stereo, or routing both channels through the same output path.
It can help reveal symptoms like swapped channels, weak separation, or phase issues, but the root cause may still be a cable, speaker, receiver, adapter, or system audio setting.