Have you ever wondered how to get your mixes mastered really loud, without crushing all the life out of them ? Maybe you've tried a bunch of different limiters, and ended up with a flat, lifeless result - or just plain distortion ?
I remember when I was training as a mastering engineer back in the early 90s, I certainly felt that way. Luckily, I had some great mentors who shared their experience, techniques and strategies with me - and since then I've trained new engineers with those same methods - plus the new ones I've figured out for myself since.
Now, if you're a regular Production Advice reader, you'll already know I'm no fan of super-compressed masters, and I spend a lot of time trying to get people to keep more dynamics in their music.
But having said that, as a mastering engineer one of the most important things I do is to balance the levels of all the songs on an album, and often that means finding the "loudness sweet spot" where the level is high, the sound is punchy and powerful and I've kept the original feel of the internal dynamics.
I wrote about this in one of the most popular posts on the site:
How to make your music loud (without killing it stone dead)
But one subject I don't cover in that post is multiband compression. That's because there simply isn't enough space in a blog post - or even, a series of posts !
So what is multiband compression, and why might you might want to use it ?
In a nutshell, multiband compression (or any multiband processing) splits the audio signal into frequency "bands", and processes them separately, without affecting the others.
That's it !
So, for example you might choose to apply particular compression settings to sounds only up to around 160 Hz - to help control the bass end without causing pumping in the high frequencies, for example.
That's multiband compression - and a multiband compressor is just a plugin or piece of hardware designed to make doing that as easy and powerful as possible. (Well, in theory, anyway - in practice lots of multiband processors I've tried are actually very fiddly and confusing to set up, unfortunately.)
There are lots of benefits to this approach - it's easier to lift the average level without pumping and distortion, you can be much more aggressive with EQ, and there are some clever techniques that allow you to sculpt the sound to an amazing degree.
And that's why multiband compression is useful in mastering - you can apply surgical processing to only one part of the audio, without messing up the rest. This is exactly the kind of control a mastering engineer needs - to subtly enhance or radically re-shape a mix. BUT:
Multiband compression can also make a complete mess of your mix.
This is powerful stuff ! The default settings on many multiband compression plugins I've tried are often very far from what I would recommend to get clean, punchy, transparent results.
Careful choices of attack, release and ratio settings are needed - and especially the placement of the frequency crossover bands - where you choose to split the audio into bands, and how many bands you use, can have a big impact on the end result.
As I said, there's much too much to say about multiband compression for a single blog post, but if you'd like to find out more, click here.
Original image by yuan2003
