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Measure how late your sound arrives, in milliseconds, with a flash and beep you line up by eye, a chirp timed by the microphone, or by tapping along.
This audio delay test tells you how many milliseconds your headphones, TV or speakers add to the sound. Play the sound through the device you want to test, pick what it is under What are you testing?, and choose a method under How to measure: Flash and beep to line the two up by eye, Microphone to let this device time a chirp it plays, or Tap along to tap with the beeps and then with the flashes.
The result is the lateness that matters for watching: how much later the sound reaches you than the browser expects. A latency test like this is the first step for a TV whose voices lag, or a pair of wireless earbuds that make every film feel badly dubbed. Take the number to the device’s audio sync setting (the TV and soundbar guide and the Bluetooth guide show where), or press Use this offset on this device so the sync player allows for it.
Connect the headphones, or play this page through the TV or soundbar (a laptop over HDMI works well). Under What are you testing? pick Bluetooth, TV, Soundbar, Projector, Console or Other.
Under How to measure, choose Flash and beep, Microphone or Tap along. The microphone is the most precise; the flash is best when you care about what you see on this screen.
For Flash and beep, press Start flash and beep (Space) and move Flash delay with 10 ms earlier and 10 ms later until they land together, then press They match now. For Microphone, press Allow the microphone, then Measure (M). For Tap along, press Start tapping (T).
Read the result, press Copy to keep it, or Use this offset on this device to save it for the sync player. Measure again runs another round.
| Method | How it works | Best for | Precision |
|---|---|---|---|
| Flash and beep | The screen flashes and a beep plays once a second; you slide the flash until they look and sound simultaneous | TVs, projectors and consoles, where the picture is delayed too | About one frame, limited by your eye |
| Microphone | This device plays a short chirp and listens for it with its own microphone, several times, and takes the median | Bluetooth headphones (earbud held to the microphone), speakers and soundbars on the same device | A few milliseconds; calibrate to remove the microphone’s own delay |
| Tap along | You tap with the beeps, then with the flashes; the difference cancels your own reaction time | A quick check without a microphone | Typically 10–20 ms of scatter |
A microphone takes its own time to deliver what it hears, so a raw reading includes it. Press Calibrate with this device’s own speaker first, with any headphones or TV disconnected: the chirp then travels the shortest path this device has, and that round trip is subtracted from later readings.
Your browser already knows part of the delay between playing a sound and hearing it, and it reports that figure to web pages. Every result here is the delay on top of what the browser reports: the part a TV, soundbar or pair of headphones adds without telling anyone. That is exactly the figure an AV sync setting needs to cancel.
| Device | Typical range | Usual cause |
|---|---|---|
| Bluetooth headphones | about 100–300 ms; low-latency modes often under 100 ms | Compression, packets and buffering in the earbuds |
| TV speakers | roughly −60 to +60 ms | Picture processing that delays the picture |
| Soundbar or AV receiver | about 20–150 ms | Decoding surround formats and room processing |
| Projector | often the picture lags, up to about 120 ms | Longer picture processing |
The Soft flash option swaps the white flash for a grey one. The test never flashes more than once a second.
The test measures the sound path of the device the page is running on. It can’t listen to a TV that is playing from a separate box while you hold your phone up to it, because the phone has no way of knowing when the TV started the beep. For that setup, play this page on the TV’s own browser or through a laptop connected over HDMI. It also can’t see inside an app that compensates on its own: many video apps already allow for Bluetooth delay, which is why a film can look fine while a game does not.
Typically somewhere between 100 and 300 ms for ordinary earbuds, depending on the codec, the phone and the earbuds’ own buffering. Low-latency and gaming modes often bring it under 100 ms. Your own pair is the only number that matters, so measure it.
Bluetooth links adjust their buffers as the radio conditions change, and tapping depends on you. Run the microphone method a few times; if the spread stays within 10–20 ms, use the median it reports.
Only if the phone plays the sound through the TV, for example over a cable or casting that carries the page’s own audio. The phone has to know when it sent the chirp. Otherwise open this page in the TV’s browser, or on a laptop connected over HDMI, and use Flash and beep.
No. It is used only while a measurement runs, what it hears is analysed on your device to find the chirp, and nothing is stored or sent.
Type it into the audio sync, AV sync or lip-sync setting of the TV, soundbar or app, or press Use this offset on this device so the sync player plays this device’s sound early by that amount.
No, it measures it. The fix happens in the device that adds the delay, or, for a video file that is itself out of sync, in the audio sync fixer.