Online Stereo Test

A stereo test checks whether your left and right audio channels are working correctly and properly separated. Using our stereo test tool, you can play tones to each channel individually (left only, right only, or both), run a stereo pan sweep that moves sound from left to right, and test channel balance by alternating between channels. This helps you identify if one speaker is not working, if your audio balance is shifted to one side, or if your stereo imaging is incorrect. Stereo testing is essential for music listening, gaming, movie watching, and any audio work where correct left-right channel separation matters. In short, it is a left right audio check: each channel must reach the correct ear.

To test your left and right speakers, follow these steps: (1) Open this stereo test page in your browser. (2) Set the volume slider to a comfortable level (around 50%). (3) Click "Left Channel" — you should hear a 440Hz tone from only your left speaker or earphone. (4) Click "Right Channel" — you should hear the tone from only your right speaker. (5) Click "Both Channels" — you should hear the tone from both speakers equally. (6) If you do not hear sound from one channel, mark "No" for that test. (7) Run the Pan Sweep and Balance Test for a more thorough check.

If you only hear sound from one speaker during the stereo test, possible causes include: (1) Audio balance is shifted fully to one side in your OS audio settings — check Windows Sound Settings > Device Properties > Balance, or macOS System Settings > Sound > Output > Balance. (2) A loose or damaged audio cable — check the 3.5mm jack, HDMI, or USB connection. (3) One speaker is physically damaged or disconnected. (4) Your audio driver has a configuration issue — try reinstalling or updating the driver. (5) A faulty audio splitter or adapter. (6) In Bluetooth devices, one earbud may have a battery or pairing issue. Test with wired headphones to isolate the problem.

The balance test alternates between the left and right channels at equal volume, playing a 440Hz tone to each side for about 800ms. If both channels sound equally loud, your audio balance is correct. If one side sounds noticeably louder or quieter, your audio balance is off. This is different from the left/right individual tests because it compares perceived loudness between channels in real-time. To fix an imbalance: (1) Check your OS audio balance settings and center it. (2) Check if one speaker is physically farther away or obstructed. (3) Clean or replace speaker grilles that may be muffling one side. (4) For headphones, check if one ear cushion is worn more than the other.

If the left test tone plays from your right speaker (or the right tone from your left), your channels are swapped somewhere in the signal path. Common causes: (1) The 3.5mm plug is not fully inserted — a partially seated TRS plug can cross the left and right contacts. Push it in firmly. (2) A cheap adapter or splitter with reversed L/R pins. (3) Speakers wired to the wrong terminals on your receiver or amplifier — swap the wires. (4) A virtual-audio driver (e.g. Voicemeeter) remapping channels — disable it and re-test. (5) Headphones worn backward — surprisingly common with symmetric earbuds. Confirm with the pan sweep: the sound should start at your far left and travel right.

No. This stereo test is designed for 2-channel (left/right) stereo audio only. It cannot test 5.1, 7.1, or Dolby Atmos surround sound configurations. For surround sound testing, you need a tool that can address individual channels (center, subwoofer, rear left, rear right, etc.) via the Web Audio API multichannel output, which is not currently supported by most browsers. If you need to test your surround sound system, use the speaker test utility built into your OS (Windows: Sound Settings > Configure, macOS: Audio MIDI Setup) or your receiver's built-in test tone generator.

Both headphones and speakers work with our stereo test, but headphones are recommended for the most accurate results. Headphones provide perfect channel separation — the left tone goes only to your left ear and the right tone goes only to your right ear, with no acoustic crosstalk. With speakers, sound from the left speaker can reach your right ear (and vice versa), which can make it harder to detect channel issues. If you are testing speakers, sit in your normal listening position (equidistant from both speakers) and ensure the room is relatively quiet. For testing headphone channel separation, the pan sweep test is especially revealing.

Yes. Our stereo test works with Bluetooth headphones, earbuds, and speakers. However, there are a few things to note: (1) Some Bluetooth devices (especially older Bluetooth 4.0 models) use a mono profile that sums stereo to mono — if you hear the left test tone in both ears, your Bluetooth device may be operating in mono mode. (2) Bluetooth audio has inherent latency, which is normal and does not indicate a problem. (3) Some Bluetooth earbuds (like modern true wireless earbuds) have independent left and right channels — test each channel separately. (4) Make sure your Bluetooth device is set as the default audio output in your OS settings before running the test.

Yes, with some limitations. To test your TV or home theater stereo: (1) Open this page in the TV's built-in web browser, or (2) Cast/mirror from a computer or phone to the TV. (3) Ensure your TV or receiver is set to stereo (not surround) mode for the test. (4) Run the left and right channel tests. Note that some TVs apply audio processing (surround virtualization, dialogue enhancement) that can affect channel separation — disable these features for the most accurate test. For home theater receivers, the built-in speaker test tone is generally more accurate than a browser-based test because it tests each speaker individually through the receiver's direct output.

Yes, our stereo test works on all operating systems — Windows, macOS, Linux, and ChromeOS — as long as you use a modern web browser (Chrome, Edge, Firefox, Safari, Opera). The test uses the Web Audio API, which is universally supported by all modern browsers. The tool creates an AudioContext, generates oscillator tones, and routes them to specific channels using a ChannelMergerNode and StereoPannerNode. For the best results, ensure your audio device is set as the default output in your OS and that no other application is exclusively using the audio device.

Clicking or popping sounds when starting or stopping a test tone are caused by audio artifacts known as "zipper noise" — abrupt changes in the audio signal that produce audible clicks. Our tool uses gain ramping (linearRampToValueAtTime) to smoothly fade tones in and out, which minimizes these artifacts. However, if you still hear clicking: (1) It may be caused by your audio driver or DAC. (2) Try using a different audio output device. (3) Increase the buffer size in your audio driver settings. (4) On Windows, try disabling "audio enhancements" in Sound Settings. The clicking is harmless and does not indicate a problem with your speakers or headphones.

No. This stereo test is 100% privacy-friendly. All audio is generated locally in your browser using the Web Audio API — no audio is recorded, transmitted, or stored. The tool creates oscillator tones and routes them to your speakers; it does not use the microphone or capture any audio input. No personal data, device information, or test results are sent to any server. You can verify this by checking your browser's network tab during testing — no data leaves your device.