👉 In physics and electronics, a loudness is a measure of the intensity or volume of sound waves. Loudnesses are typically expressed in decibels (dB), which are a unit used to quantify the difference between two sounds that have the same frequency. A decibel level (dB) is defined as the ratio of the voltage at a particular frequency to the voltage at a reference frequency, divided by 10,000. This ratio is then multiplied by 20 to get