At One Place

Metronome and tone generator

A metronome with tap tempo, and a tone generator for any frequency.

How it works

A metronome with adjustable tempo, time signature and tap-to-set, plus a tone generator producing any frequency between 20 Hz and 20 kHz.

The timing is scheduled through the Web Audio clock rather than setInterval. That distinction is the whole reason this is usable: setInterval drifts by milliseconds on every tick and is throttled outright in a background tab, so a metronome built on it audibly wanders within a minute. The audio clock runs independently of the main thread and stays sample-accurate.

Tempo markings, roughly: largo 40–60, andante 76–108, moderato 108–120, allegro 120–168, presto 168–200. A metronome marking of 120 means 120 beats per minute, which is two per second.

For the tone generator, A4 is 440 Hz by the ISO standard, though orchestras commonly tune to 442 or 443. Everything is synthesised in your browser; no audio is downloaded or uploaded.

This tool runs entirely in your browser. Nothing you enter is sent to a server, logged or stored, and the page keeps working with the network disconnected.

Common questions

Why do browser metronomes drift?
Because they use setInterval, which is not precise and is throttled in background tabs. Scheduling through the Web Audio clock instead keeps timing sample-accurate.
What frequency is A4?
440 Hz by the ISO standard, though many orchestras tune slightly sharp at 442 or 443 Hz.

Related pages

Sources

  1. Calculated on this page — At One Place

How these figures are compiled and checked