Audio latency test. How late is the sound?
Bluetooth headphones, TVs and soundbars add a delay you notice in games and on calls. This test reads what the browser reports, then measures what you really hear: clicks play, you tap along, and the gap is the delay.
One check
- Audio delay
One check after another, with your progress along the top and a plain verdict on each. Nothing you show the camera or say into the microphone leaves this page.
In short
Audio delay test: the answer first
An audio latency test measures how late sound reaches you. It reads the delay the browser reports, then you tap along to ten clicks scheduled on the audio clock, and on speakers a chirp is timed through the microphone. The median gap is the delay, wireless link included.
Reading your result
- Reported and tapped can differ
- The browser's figure covers its own path. Your taps include the Bluetooth link or the TV, which is the delay you actually hear.
- Against what people notice
- Past the warn line, late sound shows in games and when people talk over each other; past the higher line it is plainly behind.
- Bluetooth is usually the cause
- The standard Bluetooth codec buffers audio. Use a cable for games, or a headset with a low-latency mode and its own dongle.
What it measures
Measured here, not assumed.
- Reported delay
- The output latency the browser itself reports for the path to your speakers or headphones, where it shares one. Chrome and Firefox do; Safari often does not.
- Tapped delay
- Ten clicks are scheduled on the audio clock. Each tap is matched to the click before it, so a tap a whole click late is a miss and never reads as early. The median gap is the delay, wireless link included, with the slowest tenth, your own spread and the clicks that got no tap shown beside it. The first two clicks are dropped while the rhythm settles.
- Round trip through the microphone
- On speakers, a short chirp plays and the microphone listens with the browser's echo cancelling switched off. The chirp is found in the capture by cross-correlation, and the lag is the round trip, output and input together, shown beside the audio engine and output figures the browser reports. Headphones keep the sound from the microphone, so tapping stays the method there.
- Against what people notice
- Our warn line of 120 ms sits at the point ITU-R BT.1359 gives for late sound becoming detectable. From there it shows in games and when people talk over each other. Past 250 ms, our own line, it is plainly behind.
If it fails
The usual failures, and what fixes each.
- Bluetooth headphones show 150 to 300 ms
- That is normal for the standard Bluetooth audio codec. Use a cable for games, or a headset with a low-latency mode and a dongle. For video, most players compensate on their own.
- A TV or soundbar adds delay
- Switch on its game mode or low-latency mode, and turn off sound processing such as virtual surround.
- Wired audio is slow too
- Close other audio apps, which can add a buffer of their own, and check the system's sound enhancements are off.
Where a browser stops
What it cannot tell you.
- Your own timing. People tap a little early or late; ten taps and a median smooth that out, but the figure is good to about 30 ms, not 3.
- Which part adds the delay: the Bluetooth link, the headphones' processing or the system. It measures the total you hear.
- Delay inside a specific app. Video players compensate for it; games and calls cannot.
Privacy
Nothing leaves this page.
The camera and microphone are read on this page and stopped as soon as they have been measured. The clip you can play back lives in the browser's memory and is discarded when you leave. The location check discards the position. The internet test sends random bytes to this site and nothing else. The result is stored nowhere unless you ask for it by email, and then only the fact that an email was sent is kept.
Questions
Audio delay test, answered
- How do I test Bluetooth audio delay?
- Connect the headphones, open the test, press Play and tap along with the clicks you hear. The test reports the median gap between each click and your tap, which includes the wireless link, so it shows the delay you actually experience.
- How much audio latency is too much?
- Under about 120 ms, sound and picture stay together. Between 120 and 250 ms it shows in games and conversation. Above 250 ms it is plainly behind. Standard Bluetooth headphones usually land between 150 and 300 ms.
- Why do my Bluetooth headphones lag in games but not in videos?
- Video players know about the delay and hold the picture back to match. A game or a call is live, so nothing can be held back, and the full delay shows.
- Is the tapping test accurate?
- To about 30 milliseconds. People tap slightly early or late, which is why ten clicks are used, the first two are dropped, and the median is reported with the spread beside it. A tap that lands after the next click counts as a missed click rather than an early tap, so a long delay cannot hide as a short one. It is accurate enough to tell a wired headset from a Bluetooth one at a glance.
- Why does a TV or soundbar add delay?
- Picture and sound processing take time. Its game or low-latency mode switches most of that off.
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