Practical Recording Techniques, 5th Edition

Appendix A

 

dB or Not dB

 

In the studio, you need to know how to set and measure signal levels and match equipment levels. You also need to evaluate microphones by their sensitivity specs. To learn these skills, you must understand the decibel, the unit of measurement of audio level.

DEFINITIONS

In a recording studio, level originally meant power, and amplitude referred to voltage. Today, many audio people also define “level” in terms of voltage or sound pressure, even though this terminology is not strictly correct. You should know both definitions to communicate.

Audio level is measured in decibels (dB). One dB is the smallest change in level that most people can hear—the just-noticeable difference. Actually, the just-noticeable-difference ...