Audio Latency Test — Bluetooth ms
Measure Bluetooth and device audio delay in milliseconds and calibrate AV sync offset. Find whether lag is your gear or app. Free in your browser, no download.
Protect your hearing. Start at a low volume. Never raise the volume to make a tone audible. Levels are shown in dBFS, relative to full scale — not SPL.
How it works
Rhythmic metronome tap synchronization. Measures the signed millisecond difference between scheduled Web Audio hardware clicks and user input events, applying circular wrap-around normalization and statistical outlier filtering.
Audio latency is the time delay between when a sound is generated by your operating system and when the acoustic sound wave reaches your eardrums.
Where Does Audio Latency Come From?
- Operating System Audio Buffers (5–20 ms): Your OS queues digital audio samples in small buffers (typically 128 to 512 samples) to prevent stuttering.
- Codec Encoding & Framing (15–40 ms): Lossy wireless codecs (SBC, AAC, LDAC) group samples into time-frequency analysis windows before compression.
- RF Wireless Retransmissions (20–100 ms): Bluetooth 2.4 GHz packets must coexist with Wi-Fi signals. Packets that experience interference are re-transmitted, requiring an extra buffer queue on the receiver.
- DSP & Active Noise Cancellation (5–15 ms): Modern headphones run active noise cancellation (ANC) and spatial audio filters that add a slight processing delay.
Use this interactive tap test to benchmark your setup and diagnose audio-visual lag.
Frequently asked questions
What causes audio latency in Bluetooth headphones?
Bluetooth audio delay arises from three bottlenecks: (1) Digital signal encoding on your computer/phone (e.g. 1024-sample MDCT frames in AAC), (2) Wireless packet packetization and transmission over 2.4 GHz RF, and (3) Digital-to-Analog conversion (DAC) and buffer queueing inside the wireless headphones.
How does this rhythmic tap latency test work?
The test plays an isochronous metronome click every 1000ms. By tapping along in sync with the beat, human motor synchronization naturally anticipates regular beats. Transport latency delays the click, causing your taps to register relative to the scheduled click. Averaging 10 taps calculates your output latency and motor timing jitter.
What is considered good latency for gaming vs watching movies?
For gaming and music production, latency under 40 ms is essential for immediate tactile feedback. For watching movies and YouTube, delays up to 150–200 ms are acceptable because modern video streaming players automatically delay the video track to match Bluetooth audio.
Which Bluetooth codecs have the lowest latency?
Qualcomm aptX Low Latency (~35 ms) and Bluetooth LE Audio LC3 (~25–35 ms) offer the lowest latency. Apple AirPods with AAC on iOS typically measure 130–170 ms, while standard Android SBC measures 150–220 ms.