Rhythm Tap

About this test

Tapping in time looks elementary, yet it is a fine coordination task. Following a metronome properly is not about reacting to the sound: if you wait to hear it before moving, you will always be late by your reaction time, which is well over a hundred milliseconds. Good players anticipate — they build an internal pulse and the sound only corrects it.

That is why the game opens with four count-in beats, played higher. They do not count towards your score: they are there to install the pulse before measurement starts. The sixteen beats that follow are the only ones scored, and for each one your best tap is kept, as an absolute error.

Two honest remarks. First, a systematic error in one direction is far easier to fix than a scatter: if you are always late by the same amount, move your gesture earlier and the score drops at once. Second, your browser, your screen and your audio output each add a few milliseconds that are not your doing. Below fifty milliseconds or so, you are mostly measuring hardware.

How it works

The metronome runs at a hundred beats per minute, one beat every six hundred milliseconds. After four count-in beats, sixteen beats are measured: for each one we keep the absolute error of your best tap, capped at half an interval. A beat you never tap counts as that cap. Your score is the average of those sixteen errors: two hundred and sixty milliseconds scores zero, thirty milliseconds scores one hundred.