Choosing a chime that doesn't startle you

A chime that makes you jump does the opposite of what it's for. The first second after a startle is tense: shoulders up, breath held. So when we built the Inner Twitter timer, the sound got more attention than any other part.

Why the bell is synthesized

The timer doesn't play an audio file. It builds the bell sound in your browser with the Web Audio API each time a chime is due. A real bell rings at several frequencies at once, and they don't line up neatly like the notes of a guitar string. The timer mixes seven soft sine tones at bell-like ratios, gives each a gentle start and a long fade, and softens the top end with a filter.

That has a few practical benefits. There's nothing to download, so the timer works offline once the page is open. The sound can be lower or higher without a different recording. And because each tone fades on its own schedule, the chime trails off slowly instead of stopping abruptly.

The three tones

• Low and warm sits around the D above middle C, with a deep hum underneath. It's the gentlest, but it can disappear into the noise of a busy room or a laptop fan.
• Medium is at concert A. It's the default because it's easy to hear without being sharp.
• High and clear is brighter and cuts through background noise better. Turn the volume down if you use it.

Use the test button to try each one at your normal working volume.

Volume

Set it so you'd notice the chime while concentrating, but wouldn't flinch if it came during a quiet moment. Remember that the timer's volume works inside your computer's volume. If you change system volume during the day, check the chime again.

Headphones change things. A chime that's quiet through speakers can be loud right next to your ear. Try it with headphones on before relying on it.

When it still startles you

If the chime still makes you jump after a few days, try a lower tone and a lower volume. Some people also find it helps to decide in advance what the first movement will be when it sounds, for example letting the hands drop to the desk. With a planned response, the chime starts to work as a cue and stops feeling like an interruption.

If no sound works in your situation, leave the volume very low and turn on browser notifications. The on-screen prompt does the rest.