The volume unit (VU) meter has been vital in the growth and sophistication of the recording industry for years. However, very few people realize exactly what this important tool is, and how it works.

Basically, a VU meter is a tool that converts a signal level to volume units. This provides a means to take an audio signal and decipher how loud it is. A widely recognizable VU meter would be in the guise of a needle that flickers back and forth over a scale in synch with the volume of a sound being played. The louder the sound, the higher on the scale the needle would point. The purpose of this tool is to measure how loud an audio signal is, and to present that measurement in a practical, usable fashion.

Volume information can be valuable for a wide range of reasons. One of the earliest uses of these tools was for ensuring telephone lines were up to snuff. Other uses encompass everything from measuring how strong a microphone is to measuring background noise levels. With this basic understanding, it becomes easy to see how useful and versatile this tool can be. However, given such a range of usability, it can be hard to determine which situations VU meters are best used. Although the meter was developed for telephone standards measurement, its most common use today is in recording studios.

Recording studios use VU meters to determine if the sound being recorded is in the optimal range for human hearing. The human ear only registers a specific range of sounds, and sounds that are too high or too low make for a poor listening experience. These meters helped revolutionize the recording industry by providing an easy-to-read metric for determining where in that range recordings were falling. Since everyone’s hearing ability is innately different, having these easy standards to follow allowed the recording industry to produce sound recordings that are comfortable and enjoyable for the vast majority of people to listen to.

In addition, because the meter is so easy to read and can be monitored in real time, it has helped the industry streamline productions. By keeping an eye on the VU meter, a producer can make adjustments on the fly, by having sound volume increased or decreased to ensure the best performance. When recording a singing artist, the producer can glance at the meter and tell easily whether or not the singer needs to increase or decrease voice volume. Although the audio might sound fine to a producer, it may sound too loud or too soft for the general public. The meter serves as an important tool for ensuring the recording is suitable for the vast majority of ears -- not just the producers.

Although designed for a much different purpose, VU meters are standard, vital equipment in recording studios. Without these meters, the production process would include much more guesswork, and the finished product may not be pleasing to all of the intended listeners.