Phone microphone
Tap Start listening and allow microphone access. In a noisy room, move your phone closer to the music.
3.5 mm jack and audio interfaces
Connect a compatible audio interface or input adapter, then tap Start listening. A headphone output or ordinary cable alone does not provide an audio input. The adapter must support recording. Connect line-level audio to a suitable input on your interface.
Bluetooth input
Pair your microphone or headset in your phone settings. Tempo can use only inputs that your operating system makes available to the browser. Receiving music from another device requires an external receiver connected to an audio input or interface.
Check the selected input name and watch the input level. Stop and restart listening after changing connections.
Half or double tempo
Music can have more than one beat interpretation, such as 70 or 140 BPM. Use ½ and 2× to choose the appropriate one; the detector remembers your beat reference. Auto clears it. Free rhythm or weak beats may not produce a stable estimate.