Why do I hear sound from both sides when testing only one channel?

Your system is likely set to output mono audio. Go to your OS accessibility or sound settings and disable the 'Mono Audio' option to restore true stereo output.

Can this test my subwoofer?

The tool generates a standard 440Hz sine wave, which tests stereo separation but not deep bass frequencies. For subwoofer testing, you would need a dedicated frequency sweep tool.

Is this safe to use at high volumes?

The tone fades in and out smoothly to protect your equipment. Start with your system volume at a moderate level and adjust from there to avoid any surprise loud output.

What if I hear no sound at all?

Make sure the correct playback device is selected in your system's sound settings and that the browser tab isn't muted. Also check that your physical volume knob or slider is not at zero.

Online Speaker Test — Check Left and Right Audio Channels

What is the Online Speaker Test?

The Online Speaker Test generates a clear tone directed at either the left, right, or both audio channels. This lets you confirm that your speakers or headphones are wired and configured correctly — that the left earcup delivers sound to your left ear, and the right earcup to your right.

It uses the browser’s native Web Audio API, so no installation is needed and no files are loaded or transmitted.

How to Test Your Speakers or Headphones

Set your volume — bring your system and physical speaker volume to a comfortable level before starting.
Test left — click “Test Left”. Sound should come only from your left speaker or earcup.
Test right — click “Test Right”. Sound should play only from the right side.
Test both — click “Test Both” to hear a balanced tone from both channels at the same time.

Use Cases

After rewiring speakers — confirm that the left and right speaker wires are connected to the correct terminals on your amplifier or soundbar.

New headphones — check that the L and R markings on a new pair of headphones match the actual left and right channels coming from your audio source.

Troubleshooting missing audio — if one side of your headphones sounds quieter or completely silent, this test tells you whether the problem is with the hardware or a software balance setting.

Accessibility settings check — verify that “Mono Audio” or similar accessibility options aren’t accidentally activated, which would cause both channels to play the same mixed signal.

Pre-meeting audio check — quickly confirm your output audio is working on both sides before a video call, presentation, or recording session.

Why Use This Tool

Checking stereo separation normally requires finding a test audio file online or digging through your OS sound settings. This tool does it in a single click — no files to download, no settings menus to navigate. The result is instant and clear: either you hear the tone on the expected side, or something needs fixing.

Troubleshooting Common Issues

Sound comes from the wrong side — your headphones may be on backwards, or speaker wires may be crossed at the binding posts.
Both channels play on a single-side test — Mono Audio mode is active. Disable it in your OS sound or accessibility settings.
No sound at all — confirm the correct output device is selected in your system audio settings and that your browser tab isn’t muted (look for a speaker icon on the tab).