Bluetooth headphones compress and buffer sound so a moment of radio interference does not cut it out. That buffer is the delay you hear in games and calls.
- The delay a browser reports rarely includes the wireless link. Tapping along to clicks measures the delay you actually hear.
- Run the test once on the Bluetooth headphones and once on a wired pair: your own tapping habit is in both, so the difference is what the link adds.
- Our warn line is 120 ms, where late sound becomes detectable by ITU-R BT.1359; past 250 ms, our own line, it is plainly behind.
The short answer
Standard Bluetooth audio commonly lands between 150 and 300 ms on our tapping test, enough to notice in a game or when people talk over each other on a call. Video players hide it by holding the picture back to match; a game or a call is live and cannot. A low-latency mode, a headset with its own dongle, or a cable is the fix.
Why the reported figure is not the answer
Browsers can report an output latency for the audio path, and Chrome and Firefox do. That figure describes the system's side of the path and rarely includes the buffering inside the headphones and the radio link, which is the larger part. The browser is not told which codec the link negotiated either, whether SBC, AAC, aptX or LDAC.
Measuring the delay you hear
The test schedules ten clicks on the audio clock and you tap along to what you hear. The first 2 clicks are dropped while your rhythm settles, each tap is matched to the click before it, and the median gap is the delay. A tap a whole click late counts as a miss, never as an early tap, so a long delay cannot hide as a short one. People tap a little early or late, so the figure is good to about 30 ms, not 3: plenty to tell a wired headset from a Bluetooth one.
- Run it on the Bluetooth headphones, on the output you will actually use.
- Run it again on wired headphones or the laptop's speakers.
- Subtract: the difference between the two medians is the wireless link's share.
- To price a game mode or low-latency mode, run it with the mode off and then on.
What brings it down
Turn on the earbuds' low-latency or game mode in their app, if they have one, and measure the difference. For games, a headset with its own 2.4 GHz dongle or a cable removes most of it. Where both the computer and the headphones support a low-latency codec, it cuts the delay a long way. If the sound turns thin when the microphone is on, the system has switched to the hands-free output that carries the microphone: measure on the output you will use, since the two are different paths.
If the wired run is slow too, the delay is not the link. Close other audio apps, turn off system sound enhancements, and on a TV or soundbar switch on its game mode.
Terms used here
Questions
- Why is Bluetooth delay fine on YouTube but bad in games?
- A video player knows the delay and holds the picture back to match. A game or a call is live, so nothing can be held back and the whole delay shows.
- Can a website tell which Bluetooth codec I am using?
- No. The browser is not told which codec the link uses. The system's Bluetooth settings, its developer options or the earbuds' own app may show it.