Editing Mixing console (section)

===Metering===
{{multiple image |align=right |direction=vertical
|image1  =API Legacy Plus 48ch.jpg |width1=130
|caption1=Meter bridge on ''[[Automated Processes, Inc.|API]] Legacy Plus'' console
|image2  =VU Meter.jpg             |width2=130
|caption2=⇑ [[VU meter]]
|footer=<hr/>⇐ [[Peak program meter]]
}}<div style="float:right;margin-right:-1.5em;">
[[File:PPM IEC 268-10 I DIN.jpg|thumb|53px]]</div>

There are usually one or more [[VU meter|VU]] or [[peak meter]]s{{efn|Peak meters often use [[LED]]s}} to indicate the levels for each channel, for the master outputs and to indicate whether the console levels are [[clipping (audio)|clipping]] the signal. The sound engineer typically adjusts the gain of the input signals to get the strongest signal that can be obtained without causing clipping. Having the gain set as high as possible improves the [[signal-to-noise ratio]]. Most mixers have at least one additional output besides the main mix. These are either individual bus outputs or ''auxiliary outputs'', used, for instance, to output a different mix to onstage monitors.

The meters may be above the input and master sections or they may be integrated into the input and master sections themselves. Meters may have needles or [[LED]]s. On meters using LEDs, there may be different colored LEDs to indicate when there is signal present in the channel's input; the audio level of the channel, typically by lighting up more LEDs; and clipping, which may be indicated using a different colored LED. In one popular color-coding system, green LEDs indicate signal presence and the audio level; one or more amber LEDs indicate that the channel is approaching clipping; and one or more red LEDs indicate clipping.

As the human ear experiences audio level in a [[logarithm]]ic fashion,{{efn|The logarithmic response applies both to [[amplitude]] and frequency.}} mixing console controls and displays are almost always labeled in [[decibel]]s, a logarithmic measurement system. Since the decibel represents a relative measurement, and not a unit itself, the meters must be referenced to a [[nominal level]]. Most [[professional audio]] equipment is referenced to a nominal level of +4&nbsp;[[dBu]], while semi-professional and domestic equipment is usually referenced to a nominal level of −10&nbsp;[[Decibel#Voltage|dBV]].<ref>{{Cite web |url=https://www.soundonsound.com/sound-advice/q-are-all-decibels-equal |title=Sound Advice > Q. Are all Decibels equal? |last=Robjohns |first=Hugh |date=October 2003 |website=www.soundonsound.com |access-date=12 February 2020}}</ref>