VU or ‘volume unit’ meters have been around for years as a visual aid used by professional audio engineers to gauge the voltage levels of an audio signal. Today with the prevalence of digital audio recording, a different type of meter is more commonly used that presents a linear display of a logarithmic voltage scale and it’s called a ‘peak program meter’ or PPM. When you’re recording audio with a digital recording device, the rule is never allow the signal level to exceed the maximum sample level (known as 0dBFS); otherwise, you end up with clipping distortion, which sounds like your music is playing through a gravel pit. A PPM gives you a clear indication of how ‘close to the wind’ you’re sailing.