You could instead say, “the drums are 20 dB louder than the guitar”. That’s because the decibel, alone, has no value.ĭecibels are only meaningful when describing the ratio between two quantities. “The drums are 120 dB”, is an incomplete statement. When using decibels, you will always be comparing two values. This chart shows a side-by-side comparison of sound pressure levels presented as pascals and decibels:Ģ.) Using Decibels Requires a Reference PointĪ decibel is a way of describing the ratio between two quantities. It’s much easier to compare sound pressure levels when they are written in decibels, instead of pascals. The ratio between these values is 1:10,000,000! Humans are capable of hearing pressure changes from as subtle as 20 micropascals to as extreme as 20 pascals. The pascal is a unit of measurement that describes air pressure in absolute terms of force per square meter. When an absolute value is used to discuss sound pressure level, it becomes very challenging. They allow simple numbers to express values that would normally require many more digits.įor example, humans are capable of perceiving a vast range of sound pressure level, from subtle to extreme. That’s why the decibel is so commonly used to describe acoustical power, electrical power, and sound pressure level.ĭecibels are logarithmic. The decibel compares two numbers that differ by many digits and represents the ratio of those numbers with a smaller, simpler number.ĭecibels are especially useful when comparing numbers that vary by several orders of magnitude. In this section, you’ll learn how the decibel simplifies calculations and communication in audio. 1.) Decibels Can Represent Large Ratios With Simple Numbersĭecibels are used in several applications within the audio production industry.

Decibel scale zero