VU

– Stands for “Units of Volume”

– a Metering Unit to Measure a Signal Level Volume

– Mostly in Analog Devices

– Slow Response with a Integration Time of 300ms

– Ignores Signal Peaks

– Works Similar to the Human Ear,  thus a VU Meter is Useful During the Mixing Process

– Intended to Reflect Loudness of a Signal where “0Vu” = “+4dBu” (Professional Standard) = “1.23 Volts” = “-18dBFS”

– Thus a VU Meter Intentionally Slows the Metering and Averages Out the Peaks

– “-0Vu” is Equivalent to -18dBFS, means the Analog Zero is at -18dB RMS in a Digital Domain

– So Needle at Around 0dBU is the “Sweet Spot” of any Incoming Signal in Analog Equipments VU Meters  (Best Signal to Noise Ratio)

– Remember that 0dBU is Not the Same as 0dBFS, i.e. when you Reach the VU Meter at 0dBU it is Still an “Average” Level and Above that 0dBU there can be Still Up to 20dB Headroom for Peaks (Depending on the Analog Gear), while Above 0dBFS is Instantly Clipping