What is a Limiter and How to Use One to Make Better Masters From Your Home Studio
“What is a limiter and how do you use one?”
That’s a question we often get asked so I went straight to the expert for answers. Basically, a limiter is just a very aggressive compressor that tames the audio peaks and raises the overall level of your home studio mixes. However, I wanted a more elaborate answer that not only tells you why to use limiters, but also gives you some practical advice on how to use them to make your masters sound better.
Mastering Limiters – How and Why to Use Them
I’ve done – you’ve done it – we’ve all done it. You see the waveform of a piece of music slamming up to zero dB, you can see it’s had a brickwall limiter slapped across it in mastering, and you assume it’s going to sound like crap.
And sometimes you’d be right.
But not always!
In fact, there are many misconceptions about limiting, especially since the Loudness Wars have been getting more press, and too many people seem to have decided that limiters are actually evil – by definition.
Whereas in fact, when I started my career as a mastering engineer over 15 years ago, I often used only EQ and a limiter on most mastering projects as a matter of course.
Why? Because the simple truth is:
A limiter is the most transparent way
to boost average level without clipping
Hang on, I haven’t finished yet –
…provided you don’t overdo it.
So why do limiters have a bad reputation?
Because people don’t understand how to use them. The flawed reasoning is:
- I want my mix to be loud (misguided)
- Mastering engineers use limiters (true)
- I’ll use a limiter to make my mix loud (uh-oh…)
Before we look at the problems with this in more detail, we need to make sure we’re on the same page. I want my mastering limiters to be “transparent” – but what does that mean ?
What does transparent mean ?
When I say “transparent”, I mean “invisible”.
So to me, a “transparent” limiter allows me to lift the average level and prevent clipping, without hearing any adverse effects – any distortion, pumping or loss of impact. In the same way, a transparent converter won’t colour the sound in any way going from analogue to digital or vice versa, and a transparent window lets the light through without tinting it.
So now we get to Important Statement Number 2:
Any limiter will damage the sound if you push it too hard
And that, in my opinion, is where the bad reputation of The Limiter stems from.
People push them too far.
A great limiter can invisibly shave off several dB from the waveform of a mix without any audible side effects, especially if the original is good and dynamic (has a decent peak-to-loudness ratio) to begin with. That’s because transients happen so quickly our ear barely registers them anyway.
But as soon as a limiter starts to cut into the body of the sound – meaning anything that lasts more that a fraction of a second – it’s effects start to become highly audible, and usually undesirable.
(I’m talking about mastering limiters, not limiters used creatively in a mix, by the way.)
And any compressor with a ratio higher than 8:1 is approaching limiting!
As part of a mix, the aggressive gain reduction of a limiter might be exactly the sound you’re looking for. But in mastering, transparent control is the goal, usually. (Some people come to me wanting something more characterful, but personally, I think it’s better to get it right at the mixing stage if possible.)
So what’s the solution to this?
Use a compressor, then a limiter
Pushing a limiter too hard can cause a variety of unpleasant effects on the audio:
- Blunt, flat sound
- Loss of impact
- A dull, “airless” mix
- Gritty, fizzy distortion
(This is precisely because of the same characteristics that make them very transparent when used more conservatively – namely very high ratios & fast attack and release times.)
However what does work well is to use a compressor followed by a limiter.
Since the limiter will protect you against any clipping distortion, you can use slower, more natural-sounding attack times on the compressor to keep the punch and impact of the mix. These won’t catch the fast transients but will control the “body” of the sound more gently and effectively. Then the limiter can work much less hard and control all the fast transient detail – invisibly.
If you want to go a step beyond this, you could consider using multiband compression. This can be a great technique to get high levels without crushing – pulling a mix together while keeping all the punch, power and air.
Thanks for the great post Ian!
How Do You Master Your Mixes “Loud!”
To close things off, one of the biggest struggles home studio musicians have about mastering their music is making it loud enough to sound competitive next to their favorite albums.
If that’s something you are struggling with, you’ll like Ian’s video below.
This week, I just finished up my first mastering job on my new iMac after reinstalling all my software and plug-ins (Dynameter from Meterplugs and Ian Shepherd was one of the first ones to be installed natch!), but when I added my multi-band compressor to my mix, one thing was seriously lacking!
Ian Shepherd’s multi-band compression preset I use every time I master a song. So now I have to go back and watch his Mastering With Multi-band Compression video to refresh my memory of the exact preset he gave me so I can save it back to my multi-band compressor.
I’m not even sure if I know where my download link is anymore, that preset has been saved, and used and reused, over and over again throughout the years.
Anyhoo, if you want to learn to use multi-band compression to make your masters sound tighter and punchier, check out his course here.