Decibel

: Dedicated Sound Level Meters (SPL meters) use calibrated microphones to provide high accuracy for workplace or legal standards.

: 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. 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. : Dedicated Sound Level Meters (SPL meters) use