---
title: "Audio Delay Test – Bluetooth & TV Latency | sync.video"
description: "Test the audio delay of Bluetooth headphones, a TV or a soundbar with a flash and beep, a microphone chirp or by tapping, and get a number in milliseconds."
url: https://sync.video/audio-delay-test
---

1. [Home](https://sync.video/)
2. [Fix audio sync](https://sync.video/fix-audio-sync)
3. Audio delay test

Free · runs in your browser

# Audio delay test for headphones, TVs and speakers

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](https://sync.video/audio-out-of-sync-on-tv) and the [Bluetooth guide](https://sync.video/bluetooth-audio-delay) show where), or press **Use this offset on this device** so the [sync player](https://sync.video/sync-player) allows for it.

Where the delay comes from: the picture goes straight to the screen, while the sound passes through decoding, a soundbar or receiver, and a Bluetooth link, each adding milliseconds.

## How to measure audio latency

1. ### Route the sound through the device you’re testing
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**.
2. ### Pick a method
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.
3. ### Measure
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).
4. ### Use the number
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.

## Three ways to measure, and when to use each

__The three methods compared__
| 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                                      |

### Calibrating the microphone method

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.

## What the number means

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.

* A **positive** result means the sound arrives after the picture: delay the picture, or move the sound earlier, by that much.
* A **negative** result means the sound arrives first, which happens when a TV spends longer processing the picture than the sound. Delay the sound.
* Results within about 10 ms of zero are effectively in sync.

__Typical extra delay by device (individual models vary widely)__
| 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                         |

## Getting a reliable reading

1. Turn the volume up to a comfortable but clear level and keep the room quiet; the microphone method ignores echoes but not shouting.
2. For headphones, hold one earbud right next to the microphone. For a TV or soundbar, keep the microphone within a metre of the speakers.
3. Measure two or three times. The tool shows the spread; a small spread means a dependable figure.
4. If your device has a game mode or low-latency mode, measure with it on and off: the difference is often the biggest win available.

The **Soft flash** option swaps the white flash for a grey one. The test never flashes more than once a second.

## What it can’t do

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.

## Questions about audio latency tests

### What is a normal Bluetooth audio latency?

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.

### Why does my result change each time?

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.

### Can I test my TV with my phone’s microphone?

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**.

### Is the microphone recording me?

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.

### What do I do with the number?

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.

### Does this test fix the delay?

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](https://sync.video/fix-audio-sync).

## More in fix audio sync

* [ Fix audio and video out of sync Work out whether the file or the playback is at fault, then fix the delay or measure it. ](https://sync.video/fix-audio-sync)
* [ Fix Bluetooth headphone delay Reduce the lag of wireless earbuds and speakers, device by device, and measure it. ](https://sync.video/bluetooth-audio-delay)
* [ Fix audio delay on a TV or soundbar The AV sync setting on Samsung, LG, Sony, Fire TV and Apple TV, and how to measure it. ](https://sync.video/audio-out-of-sync-on-tv)
* [ Play a video in sync on several devices A room code, a shared clock and every screen playing the same frame at the same moment. ](https://sync.video/sync-player)
* [ Set the OBS Sync Offset Measure webcam or capture-card lag from a clap and enter it as the Sync Offset. ](https://sync.video/obs-audio-delay)
* [ Sync audio and video online Drop one video to fix its delay, or several files to line them up by their sound. ](https://sync.video/)