Metronome

Because they play each click the moment a JavaScript timer fires, and those timers are approximate. Rendering work, garbage collection, a throttled background tab: any of them pushes a timer late, and a late click stays late, so the errors add up over a few minutes of practice. This one splits the two jobs. A 25 ms loop wakes up and books every click that falls inside the next 120 ms directly on the Web Audio clock, at a time computed as exactly 60 ÷ BPM seconds after the previous one. The timer only decides when to schedule; the audio hardware decides when the sound happens. Jitter in the loop moves nothing.

Browsers keep the audio engine suspended until you interact with the page, so the first press of Start has to wake it as well as begin counting, and the count deliberately begins 80 ms out to give it room. If there is still silence, check that the tab is not muted and that your output is not routed to a device that is switched off.

Three. It averages up to your last six, and pausing for 2.5 seconds starts a fresh count.

With a single beat there is no downbeat to mark, so the accent is skipped even when the box is ticked.

The Italian tempo marking for that speed: Grave below 40, then Largo, Adagio, Andante, Moderato, Allegro from 120, Vivace from 156 and Presto from 176. Composers used these words loosely and the boundaries were never fixed, so read them as a rough label rather than an authority on what your piece should be marked.