Decibel Today

: If one sound is significantly louder than another (by 10 dB or more), the quieter sound barely affects the total decibel reading. Measuring Decibels

: 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. 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. : If one sound is significantly louder than

: 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. The Bel itself was found to be too

Because the scale is logarithmic, you cannot simply add decibel numbers together.

, the threshold of human hearing. In digital audio, (Full Scale) measures signal level relative to the maximum a system can handle before clipping. Examples of Common Decibel Levels