LEVELS AT A GLANCE

You can keep an eye on audio levels by glancing at these three critical indicators on the mixing desk.

VU indicator. The VU meter has been around for more than 80 years for a reason. It’s predictable, with predictable integration times and predictable release times so you can predictably read volume units. Keep in mind that the VU meter is averaging levels over time so that peaks can be higher than indicated. You can generally expect to have about 20 dB of audio headroom above 0 dBVU to encompass them.
Peak level indicator to read the transient peaks of the signal. This indicator tells you if peak levels are in danger of overloading the dynamic headroom limitations of the console. The clipping point is usually at 0 dBFS. Peak signal levels run usually at or above -20 dBFS, with transient peaks kicking up to about -6 dBFS occasionally.
Loudness indicator for compliance with the ITU BS.1770-3 and similar television loudness standards. This indicator came about initially in response to the need to assess and regulate the loudness of adverts compared to regular programming. The Loudness Unit Full Scale (LUFS) or Loudness K-weighted Full Scale (LKFS) measurement shows the averaged loudness level of audio over time, usually much longer than that of a VU meter. The average loudness target level is -24 LKFS or -23 LUFS. By the way, you can’t miss this on a Wheatstone audio console—the LKFS/LUFS numbers are two inches high on the display screen. One LU (loudness unit) is equivalent to 1 dB, so there’s a direct correlation between how far the meter says you’re over/under and how far you move a fader to compensate.