Decibel -

: Named after Alexander Graham Bell, a decibel is literally one-tenth of a "Bel". The Bel itself was found to be too large for common precision.

: A decibel always requires a reference point. In acoustics ( dB SPL ), the reference is Decibel

Because the scale is logarithmic, you cannot simply add decibel numbers together. : Named after Alexander Graham Bell, a decibel

: Many free apps are available on the Google Play Store or Apple App Store. While convenient for general checks, they may lack the calibration required for official evidence. In acoustics ( dB SPL ), the reference

Understanding dB levels is crucial for hearing safety, as prolonged exposure to sounds over can cause permanent damage. Sound Level Source / Example Perceptual Context 0 dB Threshold of hearing Near silence 30 dB Whisper, quiet library Very quiet 60 dB Normal conversation 85–90 dB Lawnmower, hair dryer Danger Zone : Risk of damage over time 110 dB Chainsaw, rock concert Painful/dangerous after short exposure 140 dB Jet engine, gunshot Immediate hearing damage The "3 dB Rule" and Adding Sound