Increase the delay until the flash and the click feel simultaneous. The value then approximates your audio output latency.
Typical Audio Latency by Connection
| Connection | Typical latency | Good enough for |
|---|---|---|
| Wired headphones / speakers | 5-20 ms | Everything, including live instruments |
| aptX Adaptive / LE Audio | 40-80 ms | Gaming, video |
| aptX | 60-120 ms | Video, casual gaming |
| AAC (typical earbuds) | 100-200 ms | Music, most video |
| SBC (older Bluetooth) | 150-300 ms | Music only |
Tip: run the test once on wired output to learn your display and reaction baseline, then switch to Bluetooth - the difference between the two readings is the wireless delay.
Audio Latency FAQ
What is audio latency?
Audio latency is the delay between when a sound is triggered and when you actually hear it. It accumulates through the whole chain: the app, the operating system audio stack, the DAC or wireless transmission, and the speaker or headphone driver. Wired outputs typically add 5-20 ms; Bluetooth adds anywhere from 40 ms (aptX Low Latency) to 300+ ms (older SBC codecs).
How does this latency test work?
The test flashes the screen and plays a click on a repeating one-second cycle. Because of audio latency, the click arrives later than the flash. Drag the slider to delay the flash until the two feel perfectly simultaneous - the slider value is then your end-to-end audio output latency relative to the display. For a stable reading, watch the flash in your peripheral vision and listen for the click.
How much latency is acceptable?
It depends on the task. For casual music listening, even 200 ms is fine since nothing needs to sync. For video, lip-sync errors become noticeable around 80-100 ms. For gaming, under 60 ms feels responsive. For playing a live instrument or singing through monitors, you want under 20 ms - beyond that the delay audibly interferes with timing.
Why is Bluetooth audio latency so high?
Bluetooth audio must be encoded, transmitted in packets, buffered against radio interference, and decoded. The codec matters most: SBC commonly runs 150-300 ms, AAC around 100-200 ms, aptX about 60-120 ms, and aptX Adaptive or LE Audio can get near 40-80 ms. Both the transmitter and headphones must support the codec to get its benefit.
What is the reported output latency shown on this page?
Browsers expose two estimates through the Web Audio API: baseLatency (the browser's internal processing buffer) and outputLatency (the estimated delay through the OS to the audio hardware). These are useful reference numbers, but they cannot see inside Bluetooth headphones - which is why the perceptual slider test usually reads higher than the reported value on wireless devices.
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