The limiter is a dynamic processing tool similar to compression. It is known to mastering engineers and is useful for optimizing the overall volume of a song. But this tool can also be useful for mixing when performing certain tasks that its cousin, the compressor, cannot perform as easily.
Limiter mode compressors and brick wall limiters
A limiter is a processing module that allows you to quickly apply a very high compression ratio. In theory, any compressor that achieves a high compression ratio (say more than 20: 1) can be considered a limiter. In addition, different compressors (LA-2A, Neve 33609, DBX 160 …) provide a selector or have a section that allows them to act as a limiter.
However, these compressors generally do not allow to know exactly the maximum output volume. This is where brickwall type limiters come in. Brickwall limiters allow you to set a volume that will never be exceeded. With their immediate attack, they set up a brick wall that audio can never get through. This important feature, of course, makes it possible to avoid clipping during mastering, but also makes the limiter extremely effective when treating tracks with strong, short tips.
The configuration
The limiter offers fewer settings than its cousin the compressor. First, there is the threshold that determines from which point the signal will be limited. This threshold can be determined by a setting that sets the threshold or can be reached by increasing the input level. Another parameter, called “ceeling” or “output level”, allows you to configure the maximum output volume. With digital audio, this ceiling is expressed in negative dB. Therefore, a ceiling of -0.2 dB indicates that the maximum volume will be 0.2 dB below the digital zero point. Very often it contains a release that, like the compressor, determines the speed at which, by limiting it, it will stop operating. Of course, one or more meters are added to show the input and output volume and the degree of reduction.
Since they are often placed at the end of the general output (master bus, main bus, or mix bus), the limiting plugins often include “wobbly” selectors that provide the ability to reduce the sampling depth (24, 20, 16, 12 and sometimes 8 bits) to correspond to the final medium. For example, we use 16 bits for a CD.
