They make your already awesome mixes louder. It allows you to take a balanced, clear, and solid mix, and then focus only on polishing that stereo mix to perfection, which includes making it louder. When using limiting (and all mastering effects really), you want to deal with the final stereo wave files, not the multi-track mixes. So if (like me) you tend to master your own material, still take the limiter off, bounce out final mixes (in 24 bit) and then bring those into a mastering session. I hear your issue already, “But what if I’m the one mastering my own music? Why not limit the mix right then and there on the mix bus and call it a day?” Great question! Like I said, limiting should really be saved for the mastering phase. Why? Because limiting is really intended for the mastering phase and your mastering engineer can do nothing with a mix that is squashed to kingdom come. When it is time to get your mixes ready for mastering, take the limiter off. And really this is only for bouncing down a mix reference for you or the client, allowing your mixes to be as loud as commercial releases so you can really compare how they sound out in the real world. The only time you really want to bring in a limiter on your mixes is at the end, when the mix is done. Instead get a great mix first, limit later. Don’t make things harder on yourself by putting a limiter where it won’t shine. You will have a skewed idea of your dynamics, and musicality can easily be lost. If you limit while you mix, you will end up fighting with the limiter. Rely solely on compression, EQ, and a your other bag of tools on a track by track basis to get things working nicely. Give yourself the “rule” that you will never put a limiter on your master fader while you are still mixing and you will go far. This can and should be done without limiting on your mix bus. Rather it should be on making your mix musical and punchy. When you are mixing tracks, your focus shouldn’t be on making your mix loud. The reducing of the dynamic range really can change the sound of a mix, especially if you are still in the mixing phase, trying to develop your sound to begin with.
The very same thing that makes a limiter helpful, is what can actually ruin your mix.
So if a limiter can quickly and easily make your mixes louder, shouldn’t you throw one on the master fader, crank it up, and bounce down the mix? Not so fast. At it’s core, a good limiter can help make your mixes nice and loud. It is built to really turn down peaks, limiting the dynamic range, thereby allowing you to turn up the volume of your track. In case you weren’t aware, a limiter is basically a compressor with a super high compression ratio. But that is very different than mixing through a limiter or limiting your mixes before mastering.
Some of the confusion may even come from people like myself who tell you to use a limiter for reference mixes. Usually what people are asking is whether or not to mix with a limiter on their master fader (mix bus). I seem to get this question a lot, “Should I use a limiter in my mixes?”.