Sound Level Converter — Decibels (dB), Nepers (Np)
Convert between 4 units of sound level — decibels (dB), nepers (Np), bels (B), and millibels (mdB). The decibel is logarithmic: 10 dB = 10× power increase, perceived as roughly twice as loud. Normal conversation is ~60 dB; a rock concert ~115 dB; a jet engine at 30 m ~140 dB. The neper uses natural logarithms and is common in telecommunications. Permanent hearing damage begins at ~85 dB with prolonged exposure.
About the Sound Level Converter
The decibel (dB) is a logarithmic unit expressing the ratio of a measured sound pressure level to a reference pressure — typically 20 μPa, the threshold of human hearing. Because it is logarithmic, an increase of 10 dB represents a 10× increase in acoustic intensity and is perceived as roughly twice as loud. The neper (Np) is used in telecommunications engineering. The bel (B) — the original unit named after Alexander Graham Bell — is rarely used because the decibel is more practical.
- ›Normal conversation: ~60 dB; a rock concert: ~110–120 dB; a jet engine at 30 m: ~140 dB
- ›Every 10 dB increase doubles the perceived loudness and multiplies acoustic power by 10
- ›The threshold of pain is approximately 130 dB; permanent hearing damage begins around 85 dB
- ›A whisper at 1 m is about 30 dB; the quietest anechoic chambers reach −20 dB SPL