Decibel (2025)

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

The is a logarithmic unit used to express the ratio between two values, most commonly sound intensity or electrical power. Unlike linear scales (like inches or pounds), the decibel scale compresses vast ranges of numbers into manageable figures, reflecting how human senses—specifically hearing—actually perceive change. Core Concepts Decibel

Because the scale is logarithmic, you cannot simply add decibel numbers together. Understanding dB levels is crucial for hearing safety,

: Adding a second identical sound source (e.g., two identical 60 dB vacuum cleaners) increases the total level by only 3 dB , resulting in 63 dB, not 120 dB. Core Concepts Because the scale is logarithmic, you

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

: The scale is not linear. An increase of 10 dB represents a 10-fold increase in sound intensity and roughly a doubling of perceived loudness.

: 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.