Multi-Band Compression

Hey guys! Dezz Asante here from TechMuzeAcademy with another MixLessons.com video quick tip. This one again comes from a fellow Gear Sluzt forum member Speakers Moon once again. He’s got some interesting question of late. He’s talking about multi-band compression.

He says,

“Hey guys! I just want…would like to know when I should use multi-band compression in the mixing process? How can I know when to use it? Is it a mandatory tool during mixing or better to leave it for the mastering process? I know that during mixing it’s often use for drums but how would I know when to start using it? I forgot to mention that I’m talking about electronic music mainly Deep House. Thanks for your knowledge.”

So,it’s a good question… and compression itself can be a bit mysterious in the begining and multi-band compression simply compounds upon on that …the mystery I suppose you could say. But lets start off with a brief explanation as to what multi-band compression is. Essentially, as you may know, what a compressor does is you set a threshold of volume, an amplitude threshold. And whenever a signal breaches that threshold, the compressor will kick in and turn down the signal. Now along with the make up game you can… when its turning down the signal you can turn the whole thing back up again. So, you don’t loose any volume and essentially, what you’ve done is you’ve brought the lower level signals up closer to…towards the higher level signals. So, you’re sort of balancing out the dynamics and making sure that none of those transients poke out too far. So, that’s essentially what a compressor does.

Now, multi-band compressor is the same thing except it works on multiple specific bands of frequencies. So, you might have the low band that’s dealing with everything from 80 hertz and below. And thats a compressor…independent compressors working on just those frequencies.And then you might have the a mid band that’s you know…you might say going from say…I don’t know low-mids say 100, say 400, 500 and it’s a full-out compressor working on those bands and so on. So, you can have 3, 4, 5 bands depending on the compressor that you’re using.

So, the idea with the multi-band is so that you’re able to apply compression frequency based. So, if you’re overall signal is pretty good but maybe there’s some mid-range transients that are just a little…excuse me a little irritating to the ear perhaps harsh or what have you. You can use the multi-band to isolate those frequencies and have them be compressed in a particular manner. Just those frequencies. So, that’s what a multi-band compressor is.

Now, in answer to your question – is it mandatory? Absolutely not! I’ve made many a mix that sound just fine, clients were happy and paid me that did not use multi-band compression at all. However, I’d like to leave you with one idea that I got from mix engineer Charles Dye. If you don’t know Charles Dye just look him up. His name is Charles… D-Y-E …Dye. He is a big proponent of software mixing. He probably has most notoriety for the Living La Vita Loca which I believe was the one of the first hit records that was produced entirely or mix entirely in the box. So, feel free to look him up. He is also a great teacher. But he brought accross the idea of using the multi-band compressor as sort of a dynamic EQ. And this was an idea that really intrigue me and I’ve been playing around with it eversince. Essentially what he likes to do and I can say now I also like to do, is I like to put a multi-band compressor on my stero bus. And its not doing very much. What I do is I take each of the bands, thresholds down to the point where that band is just activating, its just compressing a  tiny, tiny bit. I’ll do same for each band just bring them down so that line in most multi-band compressor plugins there’s a graphical display.

So, you can see a wear along frequency spectrum its being compress. So, you’ll your low-frequencies being compress and your mid-frequencies being compress. And you’ll see these little lines just just dancing away as the various frequencies are receiving the compression, as they breach the threshold by a litle bit. And I’m talking a very small amount of compression, a DB maybe at the most. And what I’ll do is I’ll put this on very early in the mix process and I’ll mix through it, I’ll mix into it. And I find what this does it has the effect of…sort of smoothing out my EQ curve because like I say you know your compressor is dealing with volume levels and the multi-band compressor is dealing with volume levels of individual levels of frequency bands. So, essentially its in real time dynamically EQing your track, your entire track to sort of stay…it’s difficult to explain…to stay within a certain threshold… to stay …sort of smooth around the edges. I find…and this is something I encourage you to experment with. I find that when I’ve mix through the multi-band compressor with just a very subtled amount of compression on each band when I disengage the compressor my mix tend to sound a little …spiky I guess you could say for a lack of a better term. Those transients start poking through again and there’s… like a rough around the edges kind of a sound to the mix which might be appropriate if you’re going for. And again this is something I’d like to play around with not in every circumstance but because it all depends on the musical situation and as you know every musical situation is different.

But I encourage you to try to think of your multi-band compressor as a dynamic equalizer and to try to approach it from that perspective and experment with the settings of the threshold with the attacks, the releases without typically I do is pretty much leave everything as the stock preset and then just drag my thresholds down until that line is starting to wiggle and dance a wee bit and then ofcourse adjust your makeup game so that you’re not loosing any volume or any amplitude in the mix and then mix through it. Make all of your decisions with that plugin engaged and then when you got a good sounding mix that sort of pleases your ear try disengaging that multi-band so you can hear the difference before and after. Again, gain stage make sure your… the volume of mix is the same whether the plugin is engaged or disengaged because that’s the only way your truly going to get a good idea into what the plugin is actually doing.

So, again thats just one of the many ways that you can approach a multi-band compressor but I just want to leave you with a quick explanation as to what it is and one interesting and perhaps somewhat unorthodox method of using one that I picked up from mix engineer Charles Dye. And again, look him up. He’s got lots to teach. He’s a very good, well spoken instructor as well and hes got a product called “Mix It like A Record”. That’s a dvd tutorial on modern in the box record mixing. So, highly recommended. Check it out and I hope that helps.

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