5 Uses for Multiband Compression (Without Ruining your Mix)

MC comp

How it Starts

Every multiband compression tutorial starts the same way. “The first time I tried multiband compression, it completely ruined my mix. It sounded awful!” 

They don’t even tell you what was bad about it. The message is simply: beware of multiband compression, the great mix killer.
You know, as opposed to all those other audio tools that only make your mix better. Take a saturation plugin for example. Slap it on your mix buss, turn the distortion to 11 and viola! You definitely did not just ruin your mix. Had you tried that with multiband compression, all your hard work would be in shambles.
Okay so here’s what I’m saying. Multiband compression is an audio tool, just like all the other audio tools. Which is to say there’s a time and place to use it. If you don’t need it, don’t use it.
But if you do need it and you don’t use it because you’re intimidated by it? Well then you’re not doing yourself any favors.
So when does multiband compression come in handy? Let’s see a few examples.

When to Use Multiband Compression 

Example 1 – De-Essing Sibilant Vocals 

I’m not even going to explain this because you already know how valuable a vocal de-esser can be. And yes a de-esser is an example of multiband compression. Because it only compresses select frequencies rather than the whole signal. So multiband is already less evil than we thought!

Example 2 – Scooping mud out of a flabby bass sound 

Synth bass patches are notorious for too much sauce in the low mids. They muddy up the whole mix. Using multiband compression, you can rebalance the sound a bit.
Maybe the signal under 100hz is inconsistent, so smoothing out the subs and boosting them a couple dB will give it a more proper weight. Maybe in the 800-1200 range there’s a big drop off in signal. But if you can pull that up a little bit, there’s suddenly more clarity. Instead of having a big hump in the frequency spectrum around 250hz, the sound is more balanced now. And will hopefully sit better in the mix. That’s the goal after all.

Example 3 – Slap bass that POPS 

Compressing slap bass is tricky. Similar to the previous example, there’s important frequencies far apart in the spectrum.
The low thump is vital to preserve, and the high pops equally so. And in this case especially, you want don’t want to lose the dynamics of the performance. So say you dial in a regular compressor to accentuate the hi popping notes. You find that as a result, you’ve completely squashed the low notes. They were louder after all, and were more greatly affected by the compressor. If only there was a way to have separate compressor settings – one set appropriate for the high notes, and another appropriate for the low notes. Oh right, that’s the very definition of multiband compression.

Example 4 – Unruly Multi-Layer Synth Patches 

Imagine a layered, full spectrum synth patch. The kind that sounds like a whole song in one note. These often don’t need any compression at all. But lets say there’s a high fluttering layer with a nice twinkle. But whenever it gets to a certain note, a resonant peak jumps out and pierces your ears. Meanwhile, you don’t have a bass line in this song. It’s an ambient track and you were hoping the low layer of this synth patch would suffice for the bass. But now it’s sounding weak in the mix.
Multiband compression time. Treat the piercing highs with a similar approach you would for de-essing. Narrow in on the problem frequency. Set the compressor threshold so it turns that down without affecting the rest of the sound. Use the compressor’s low band to squeeze and raise the bass frequencies, filling in the hole you noticed in the mix.

Example 5 – An underweight kick drum sample 

Okay, usually for this I would just layer in another kick sample with more sub frequencies. But lets say that’s not an option. Using a multiband compressor, you can access those sub bass frequencies and thicken them up. Just like in the previous examples.

Bonus tip!

Now you have a bass heavy electronic song. There’s a monumental bass riff and 10 ton kick drum to boot. Here’s a classic case for side chain compression on the bass, lowering it’s volume whenever the kick hits. But this bass riff is monumental! Full spectrum, the meat of the song! We don’t want to hear the high frequencies being sucked out by the kick drum. The riff is supposed to be tearing our faces off, not hiding from every down beat.
Enter Multiband Side-Chain Compression. You’re goddamn right I went there.
Put the multiband compressor on the bass. Side chain the kick to the low frequency band only. Now only the sub frequencies of the bass duck out for the kick drum. This fixes the problem and leaves the rest alone. A much more transparent solution than the usual alternative.

Ps. If you don’t know how to use a compressor and you try to use a multiband compressor, you will multiply your mistakes. Don’t ruin your mix!

But really, don’t be afraid to practice and improve your skills. The only way to make a great mix is to make many many bad ones first.