01What's that sound?
The short version: Search everything in this guide by what you are hearing - "humming at night", "beeping crosswalk", "siren that rumbles", "jackhammer at 7am", "train horn", "birds singing at 3am" - and jump to the explanation. Below it, the decibel ruler puts the sounds in this guide on one scale, from rustling leaves to a jet engine, with the hearing and noise limits marked.
175 things you might hear
Every sound on one ruler
Each bar is a sound level reported by a source cited in this guide. Decibels are logarithmic: every 10 dB step is ten times the sound energy and sounds roughly twice as loud, so the bars near the top of the scale are far louder than they look. Levels depend heavily on distance and conditions, so tap a bar to see the measurement and its source.
47 sounds, quietest to loudest
Tap or focus a bar to see the source and conditions.
The limits drawn as dashed lines
- 50 dBA Boston night limit - City Code 16-26, 11 p.m.-7 a.m. source
- 55 dB Lden EU noise map reporting threshold - 24-hour, with evening and night penalties source
- 65 DNL US airport noise threshold - yearly average; homes, schools, hospitals incompatible at or above source
- 67 dBA Leq(h) FHWA Noise Abatement Criteria, homes - exterior, hourly source
- 85 dBA TWA NIOSH recommended exposure limit - 8-hour average, 3 dB exchange rate source
- 90 dBA TWA OSHA legal limit (PEL) - 8-hour exposure, 5 dB exchange rate source
- 100 dB LAeq,15min WHO safe listening venue cap - Average over any 15 minutes (2022 standard) source
- 140 dB peak OSHA impulse noise ceiling - Peak sound pressure level source