Peak meter is a type of visual device that indicates instantaneous level of an audio signal that is passing through it. In audio, the meter, whether peak or not, usually is used to correspond to the loudness of a particular signal.

In modern audio equipment, peak meters are usually made up of a series of LEDs (small lights) that are placed in a vertical or horizontal bar and light up sequentially as the voltage increases. There are many variations on how this is implemented. A peak meter can also be implemented with a classic "VU style" moving needle device such as you see on older analog equipment (similar in appearance in some ways to a pressure gauge on your bicycle pump), or by several other means.

The term "peak" is used to denote the meter's ability, regardless of the type of visual display, to indicate the highest output level at any instant.

Perhaps it's easier to describe this through contrast of an older style of metering, which used actual moving parts instead of lights to indicate the audio level. Because of the mass of the moving parts and mechanics, the response time of these older meters could have been anywhere from a few milliseconds to a second or more. Thus, the meter might not ever accurately reflect the signal at every instant of time, but the constantly changing level, combined with the slower response time, lead to more of an "average" indication.

By comparison, "peak" type metering is designed to respond so quickly that the meter display reacts in exact proportion to the voltage of the audio signal. This can be useful in many applications, but it should be noted that the human ear works much more like an average meter than a peak meter, and thus, many audio engineers and sound professionals prefer to use older analog style metering because it more accurately relates to what a human listener will experience in terms of relative loudness.

See also

• Peak programme meter (A quasi-peak meter originally developed by the BBC)
• Audio equipment
• VU meter
• Decibel#Acoustics