Room tone & noise floor meter

How quiet is your room, really?

Drop in a chapter, an episode or a test recording. You get its noise floor the way ACX measures it, every pause long enough to be room tone with its own level, any dead air where an edit left digital silence, and the room tone at the head and tail. Drag across the plot to measure any stretch. Measured in your browser; nothing is uploaded.

Drop a recording: a chapter, an episode, or a test take of your room

MP3, M4A, WAV, AIFF, MP4 and MOV at any length; other formats up to 64 MB. Measured in your browser; nothing is uploaded.

The noise floor

ACX requires a noise floor no higher than −60 dB RMS, and Spotify for Authors’ guide says the same. Neither says how to measure it, so this follows Audacity’s ACX Check: the RMS of the quietest 0.4 seconds in the file, unweighted. That’s one window, so one quiet breath can flatter it; the pause list shows what the room sounds like across the whole recording.

Remember that mastering moves the floor with everything else. Raising a quiet chapter by 8 dB to reach ACX’s RMS range raises the room tone by 8 dB too, so a floor of −65 dB before mastering can be −57 after.

Dead air

A pause that measures as digital silence usually means an edit was filled with silence rather than room tone. Through headphones the room switches off and on, and ACX asks for room tone, not silence, between and around the narration. The tool marks any pause under −90 dB (Audacity’s warning level; ACX gives no figure).