First I go over what a limiter is and what it’s used for, then I’ll explain all of the parameters of a limiter plugin. And finally, I’ll show you how to use limiters in a mix or a master.
A limiter, in a nutshell, is basically a compressor, but with a very high ratio setting. Now if you’re not sure what a compressor is, I’ll give you a brief explanation as it’s important to know this to be able to understand a limiter.
A compressor is a dynamic range processor. It can be used to reduce the level of a signal when it gets over a particular loudness threshold. Compressors can also increase the overall level of a signal, allowing us to reduce the overall dynamic range, essential squashing the signal in terms of it’s volume. Now, how much the signal is reduced by, depends on how high you set the ratio. So a ratio set at 2:1, will reduce the signal by 1db for every 2db that goes over the threshold.
So a limiter can be defined as a compressor with a very high ratio, for example, 20:1, all the way up to infinity:1. A limiter with an infinite ratio would be called a peak limiter or a brickwall limiter, because it blocks the signal from peaking/clipping at 0db. This is often used in mastering, where there’ll be a hard ceiling at 0db or -1db, and the level will be increased, pushing it up against that ceiling which stops the audio from going over. You’ll see this in action in part 3 of the video. So technically all limiters are compressors, but not all compressors are limiters.
There are some misconceptions that compressors and limiters are completely things. Or that for it to be classed as a limiter it has to be a brickwall limiter with an infinite ratio. But really there’s no specific ratio where suddenly a compressor becomes a limiter, it’s more about how it’s used. And this is why you often get plugins, or more commonly hardware compressors, that are labelled as “compressor limiters”. Watch the video to see part 2 and 3 where I explain all the main parameters and show you how to use a limiter in action.