Audio Latency Test
Bluetooth delay = median round trip with the earbuds minus median round trip on the built-in speaker. For example, 240 ms with earbuds and 60 ms on the speaker means the earbuds add 180 ms. Common Bluetooth earbuds add roughly 150 to 300 ms; this test plays chirps and times them through your microphone.
How to use
- Unplug or disconnect headphones so sound comes from the built-in speaker, then press Measure built-in speaker and allow the microphone. Keep the room quiet for about 10 seconds.
- Connect your Bluetooth earbuds or speaker. Hold an earbud right next to the laptop or phone microphone (or point the speaker at it) and press Measure Bluetooth.
- The tool shows the median round trip of each run, how much the clicks varied, and the difference between the two runs: that difference is the delay Bluetooth adds.
- No microphone? Switch to Tap test. Tap when the square flashes, then tap when you hear the beep. The gap between your two reaction times is a rough estimate of the sound delay.
How it works
Mic test mode plays 8 short chirps (8 ms sweeps from 1.5 to 6 kHz) at random intervals of 1.0 to 1.4 seconds. Echo cancellation, noise suppression and automatic gain are turned off so the recording is not altered.
The recording and the playback share one Web Audio clock. For each chirp the tool cross-correlates the recording with the chirp shape (a matched filter) over the next 900 ms and takes the strongest peak, refined to a fraction of a sample. Round trip = arrival time - scheduled play time.
A peak counts only if it stands at least 12 times above the noise level of that window and its shape matches the chirp (normalized correlation of 0.3 or more), so speech, beeps or silence give a failed reading instead of a random number. The result is the median of the detected chirps, with the median absolute deviation (MAD) as the spread.
The round trip includes output delay (speaker or Bluetooth) plus input delay (microphone). Measuring the built-in speaker first and Bluetooth second with the same microphone cancels the input part: Bluetooth delay = Bluetooth median - built-in median.
Tap test: audio delay estimate = median sound-tap time - median flash-tap time. Taps faster than 80 ms or slower than 1.5 s are ignored. Reaction to sound and to light differ by a few tens of milliseconds from person to person, so treat this as an estimate only.
FAQ
What is a normal Bluetooth delay?
Common Bluetooth audio (SBC or AAC) usually adds roughly 150 to 300 ms. Gaming or low latency modes and newer codecs can be much lower. Wired headphones and built-in speakers add only a few milliseconds beyond the system buffer.
Why should I use the laptop or phone microphone, not the earbuds' microphone?
When an app opens the microphone of Bluetooth earbuds, most systems switch the earbuds to the hands-free (HFP) profile. Sound quality drops to phone-call level and the delay changes, so the number no longer matches music or video playback. Pick the built-in microphone in your system settings before testing.
Why does it say the signal was too weak?
The microphone did not pick up the chirps clearly. Turn the volume up, hold the earbud closer to the microphone, and keep the room quiet. Some phones apply processing that cannot be turned off from a browser.
Why is the spread large?
Bluetooth links sometimes adjust their buffer while playing, and background noise can cause false peaks. Run the test again, and if values keep jumping, the delay of that device really does vary.
Does this match the delay in games and videos?
Video players and many TVs shift the picture to match Bluetooth delay, so you may not notice it there. Games and music apps that need instant sound cannot hide it, which is where this number matters most.
What are the output latency and base latency values?
They are what the browser reports about its own audio buffers. Some browsers report 0 or nothing, and few include the Bluetooth link, which is why the tool measures the sound acoustically instead of trusting them.
Is anything recorded or uploaded?
The few seconds of microphone audio are analysed in memory on this page and discarded. Nothing is uploaded.