A VU meter is an essential device that lets you monitor the audio levels in a circuit. This tells you if the volume of the audio is too loud for your equipment to handle, which would cause distortion, a usually undesirable effect caused by overly loud audio. Based on old analogue technology, the meter has a set of numbers written on it. In the negative range (say -48 to 0) the audio is at the appropriate level. Above 0, in the positive range, the signal is too loud and distortion, also known as clipping, will result. Warnings Writer Bio

How to Connect VU Meters to an Amp - 90