VU Meters are essential in the pro audio world. VU stands for "volume unit" and it is an instrument used to measure signal level and dynamics of sound. VU meters provide a visual indication of the signal level – they display the magnitude whatever signal is sent to them. VU Meters are especially helpful in measuring loudness, gain staging, and mixing audio. VU Meters together with a spectrum analyzer can help pro audio engineers "tweak" a signal until it's perfect. VU Meters are incredibly useful tools that allow engineers to make sure their mixes are balanced, properly EQ'd, and correctly compressed without any distortion or clipping of sound waves. In summary, VU Meters have an integral role in ensuring that pro audio sounds its highest quality imaginable!