Room Tone Generator: loop your own room tone free

Where it runs

Works in a current Chrome, Edge, Firefox or Safari, on Windows, Mac, Linux and Chromebook computers, Android phones, iPhones and iPads. Nothing to install, no account.

The first file loads the audio engine (ffmpeg, about 31 MB) once, and your browser keeps it. Very long books are easiest on a computer, which has more memory than a phone.

4 simple steps.

Drop a take

A chapter or a session recording with a few seconds of silence in it, from the same room and mic.

Pick the quietest stretch

The three quietest stretches of real room tone are marked. Listen to each; breaths and clicks are left out.

Choose a length

From five seconds to five minutes, as 24-bit or 16-bit WAV for editing, or 192 kbps MP3.

Drop it into your edit

Fill gaps, pad the start and end of chapters, or lay it under pickups so the background never changes.

Using room tone in an audiobook edit

Gaps and cuts: where you removed a mistake, fill the hole with room tone rather than silence.
Chapter edges: ACX asks for 1–5 s of room tone before the narration and after it.
Pickups: record a few seconds of room at every session; use that session’s tone around its pickups so the background matches.

Always record 10 seconds of room tone at the start of a session, mic and gain as you read, not moving. Check your room first with the noise floor meter. audiobook.tools is not affiliated with ACX or Audible.

Questions, answered.

What is room tone?

The sound of your recording space when nobody is speaking: the quiet hiss of the mic and preamp, the air, the room. Every recording has it, and listeners notice when it suddenly changes or drops to digital silence.

Why not just use silence?

Digital silence sounds like the audio cut out, and ACX asks for room tone and a consistent noise level, not silence. Gaps, chapter heads and tails should be filled with the room tone of the same session so the background stays continuous.

Won’t a looped stretch sound repetitive?

Loops of noise click or pulse where they join. Here the stretch plays forwards, then backwards, then forwards, so every join meets itself sample for sample. Pick the longest quiet stretch you have: more variety, less pattern.

How much room tone does ACX want?

Between one and five seconds at the start and at the end of every file, with no silence longer than five seconds, and a noise floor of −60 dB or lower. ACX mastering pads the start and end for you; this tool is for gaps and edits.

Is my recording uploaded?

No. It is measured and cut in your browser and never leaves your device.