Decibel Site

: 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.

: 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.