STEREO / FREE BROWSER TOOL
Check whether sound comes from the correct side of your headphones or speakers. Start the alternating test, or choose a single channel. The large LEFT and RIGHT labels follow the audible tone.
Ready. Start with your device volume low.
Listen for left, then right. Stops after 8 seconds. Escape stops playback.
LEFT should come from the speaker on your left; RIGHT from the speaker on your right. Both / mono plays an identical signal in both channels. This checks routing and gross level differences. It does not measure frequency response, distortion, acoustic phase, or loudness in decibels.
Turn off mono audio in your device accessibility settings and check your cable or adapter. Some wireless speakers combine both channels into a single enclosure. Spatial audio, sound enhancement software, and Bluetooth routing can also change what you hear. If one side is silent, try another output before deciding that a speaker is faulty.
Start the alternating test at a low volume. The tone marked LEFT should come from your left speaker and the tone marked RIGHT from your right. Use the individual channel buttons to repeat either side.
Your device may be using mono audio, virtual surround, or a speaker that combines the two channels. Check system accessibility and audio enhancement settings. The browser cannot override your operating system routing.
Yes. Alternating channels should move from side to side in a stereo setup. Both / mono sends the same signal to both speakers. If the alternating sound stays in the center, inspect mono settings and your hardware.
The test uses browser-generated audio and starts after a tap. Phone speakers may not provide clear stereo separation; headphones or separate speakers make channel identification easier.