A complete surround sound test, free and in your browser: check your 5.1 or 7.1 channel by channel, see which audio format is actually reaching your receiver, and find out why your TV keeps folding everything down to stereo.
This tool checks your surround sound end to end, in the browser: which channels really play, what audio format reaches your receiver, whether sound is in sync with the picture, and what to change when something is wrong. It uploads nothing and never touches your gear — it guides you.
How to use the tool
At the top you will see your audio output (the channels the browser detects). From there, each tab does one thing:
- Guided diagnosis: tell it your setup and the symptom and it walks you, with questions and tests, to the cause and the fix.
- Channel test: it sends a signal to each speaker (front, centre, surround, sub) and you confirm which one plays. It needs a multichannel output (a PC over HDMI with the system set to 5.1/7.1); on a phone or stereo it tests left/right and polarity.
- Format probe: it plays multichannel sound and you read on the AVR display what it shows (Dolby Digital, Atmos, DTS:X…), so we know whether your connection lets that format through.
- Lip-sync: an on-screen flash synced to a click to set the audio delay. It only works if the app screen is your TV.
- Fix it: the checklist that solves most cases, with the setting hint per TV brand (Samsung, LG, Sony, Panasonic, Philips, TCL, Hisense).
What it can and can't measure
Let's be honest about what a browser can do. It can: send a real signal to each channel, help you read the format that arrives, and help you set lip-sync. It can't: force your gear's eARC or CEC on, detect the format automatically, or send an Atmos bitstream. What you hear is what the browser outputs; the mapping to each speaker is done by your OS, the HDMI link and the AVR, so set the output to 5.1/7.1 for the channel test.
When to use each test
- No sound or stereo only → Guided diagnosis and Fix it.
- No Atmos or DTS:X → Format probe.
- A speaker missing or surround swapped → Channel test.
- Audio lagging the picture → Lip-sync (and for the acoustic side, the audio delay calculator).
Surround, Atmos and DTS:X in 30 seconds
Surround needs the TV to send the audio without downmixing to stereo, and the connection to carry the format: optical only passes Dolby Digital and DTS 5.1; ARC adds app Atmos; lossless Atmos and DTS:X only pass over eARC, with an Ultra High Speed cable. If you want the full why, it's in the guide on why surround sound fails.
Frequently asked questions
How do I test my 5.1 surround sound?
In the "Channel test" tab: if your output is multichannel (a PC connected over HDMI with the system set to 5.1/7.1), the tool sends a signal to each speaker and you confirm which one plays. On a phone or a stereo output you can only test left/right and polarity.
Do I need a PC or is a phone enough?
The discrete channel test needs a multichannel output, normally a PC or laptop wired over HDMI with the OS set to 5.1/7.1. On a phone the other tabs still work (format probe, step-by-step fix, guided diagnosis) plus the left/right test.
Can I test Dolby Atmos?
The tool plays multichannel PCM and you read on the AVR display which format is arriving; a browser cannot send an Atmos bitstream. The format probe tells you whether your connection (ARC, eARC or optical) can carry Atmos at all.
Why do I only get stereo?
Usually because the TV audio output is on PCM instead of "Pass-through/Bitstream", or the content itself is stereo. The "Fix it" tab walks you through it step by step.
How do I know if a channel is wired wrong?
Use the guided channel test: if the left surround plays on the right (or vice versa) your wiring is crossed; if a channel is silent, check its assignment, cable and speaker.
Can I test 7.1?
Yes. If your output has 8 channels the tool adds the rear speakers (RL/RR) to the map.