Are all compressors the same? – An overview.
If you’re the least bit serious about your musical activities and are partaking in some good old recording or mixing (of course you are!), you will most certainly have heard about compressors.
In this article, I’ll assume that you have read all about what compressors do (and what they don’t do), so I’m not going to recap a complete discussion about compressors and how to operate one here. Partly because that’s going to be covered soon in an episode of Start To Mix, and partly because I really don’t want to publish yet another guide about what compression is exactly. As you know, I like to take a different approach here.
So what I will cover, is a question that may be burning in the back of your mind right now:
Are all compressors the same?
Yes, you’ve heard about compressors. And yes you do know what they do and how to operate one. But in your research, you will have come across a wealth of different compressers. Freeware, hardware, paid plugins… There’s a bunch!
So what’s up with that? Why are there so many and why do they keep making different models? Aren’t they all basically the exact same thing? Don’t they all need to perform the same function, most notably: keep audio peaks in check?
Well, here’s a short and easy answer for you – an answer you might have expected already: of course they are not the same. They are in fact very different in design, sound and functionality.
The longer answer requires us to take a look at what different types of compressors there are around and in what characteristics they can vary.
Time for a concise overview! Let’s dive right in and talk about:
- tonal characteristics,
- functional characteristics,
- and design characteristics.
At the end of the article, we’ll have a round-up of some of my favorite compressors, in each category.
This is, in my opinion, the major dimension in which compressors differ from one another.
We can talk about functionality and different layouts all we want (and we will, just a little bit later in this article). But what it boils down to is that when we’re mixing, we prefer the actual sound of a particular compressor over another.
In fact, the preference of the sound of one compressor over another will most definitely change in different situations. That’s because different compressors have different tonal characteristics.
With regards to tone, there are those compressors that do add a lot of color to your sound and then there are those compressors that (almost) don’t add any color to your sound. Let’s talk these through in order.
Compressors that do add color to your sound
One one end of the spectrum, we have those compressors that will add color to your sound in addition to performing compressor specific tasks (reducing peaks & shaping transients).
A very prominent example of an aggressive compressor with big crushing abilities and tonal coloring, is the Rough Rider by Audio Damage. It’s not really a tool that I myself would promote to use when balancing a mix, it’s simply to aggressive for my taste. However, I do absolutely love it for doing sound design, exactly because it’s got such sound mangling abilities.
A cross over example of using it in a balancing/sound design situation would be to using it for some very aggressive side chaining – for example the kind of pumping we’re used to hearing in EDM. Why don’t you try it out and see how much energy it can bring to your song?
All in all, this kind of extreme shaping compressor is great for sound design – not so great when it comes to balancing. A less extreme coloring compressor, on the other hand, is of course very useful indeed – An example would be something analog or a modeled plugin,… but that’s for just a bit later in this article.
Compressors that don’t add color to your sound
On the other end of the spectrum are compressors that don’t add too much color to the sound. They are reasonably cold and simply serve to keep your peaks in check or do some clean transient shaping.
One of the compressors I like to use for simply keeping peaks in check, is the stock compressor that comes with Logic (with algorithm set to platinum). There’s not too much to say about these ‘surgical’ compressors, other than the fact that they keep peaks in check – and don’t add to much color to the sound. They’re great to use as a first measure on vocals or rhythm guitar, where you don’t want to change the source sound too much, but in my opinion not so great on a group of tracks – for example a drum bus.
It’s all up to your own taste of course, but I like to give my drum bus some color and either use an outboard compressor (like the DBX 160), or a plugin that was modeled after one.
Compressors don’t only differ in sound, the various models around also serve very different purposes. Sure, there are certain “one size fits all” types of compressor, but there are a number of reasons why one would opt for a compressor that serves only one purpose.
For one, if it only does one thing, it’s likely that it does this one thing very well. Secondly, simple plugins are a lot friendlier to your CPU – which might not seem like its something you need to look out for, but just wait until you’re mixing songs with +50 tracks that need processing.
Lastly, there’s just a certain charm to using specialized units or plugins.
Over the years I’ve come across several compressors that were basically some sort of a combination of all the functionalities compressors can have, either adaptable or not! Input gain, attack, release, auto release, ratio, make up gain, auto make up gain, Sidechaining, frequency band specific compression… And the list goes on. The offer ranges from one-knob-does-it-all compressors, to omf-wtf-are-all-these-twiddlebits kind of machines.
And that, is where design differences come into play.
So different compressors have different functionalities and various sonic colors. As mentioned before, a one size fits all machine would be nice, but it’s just not really practical for a variety of reasons. That’s why we can come across very different compressor designs when we’re shopping around. They range from very complex to really, really simple. The beauty of it? Whatever your needs, you are sure to find a compressor that’s a great match.
Simple “one knob” compressors
This is the most simple implementation of a compressor possible. This is where the designers of the plugin/hardware model, made a conscious choice not to over complicate things. They opt for a threshold (or peak reduction, or whatever they call it) control, often coupled with a sort of “behind the scenes” auto make-up gain function.
Now, while these designs are fun to play with, I would advise you to steer clear of going the “easy way” and just getting a one knob compressor. Sure, it’s simpler, but you do lose a lot of control that is in fact absolutely vital when you’re compressing. One reason being that there’s no way that one set attack/release time will work on every single track.
In fact, it’s the opposite: every track requires careful considering which attack/release times are the best.
Analog, hardware compressors:
Analog compressors exist in all shapes and sizes. That being said, for me there’s one thing that differentiates them from some compressor plugins: their analog design implies that they do add color to the sound they’re working with. This, for some, is an important reason to opt for an analog compressor in your arsenal.
Now, I could very well write out a big list of compressors that have been praised over the years as being excellent hardware units. I’m not going to do that, however, because Attack magazine already did the work for me. It’s from 2012, but the arguments still stand. These are hardware monster comps that stood the test of time and it’s a good idea to cruise through the list to see if there’s anything you would like to try.
My personal favorite, for a drum buss at least, is the simple DBX 160 – great sound, easy to use,… you’ll love it.
Comps that are modeled after analog stuff
Well, here’s where the beauty of VSTs (and other plugin formats) comes into play. Analog compressors sound amazing, sure, but they’re also a little pricey to say the least.
So… Hardware compressors too expensive for ya? Find an emulated version for less than 1/10th of the price!
Back in the day, emulations weren’t really working as well as their analog counterparts, but nowadays, with increased computing power they’ve become really, really, REALLY good. Time to shop around. What to get? Well, this is again personal preference, but a couple good ones are:
- Tube-Tech CL-1B Opto Compressor
- Softube Valley People Dyna-Mite Compressor/ Limiter
- Native Instruments Sold Bus Compressor
- Native Instruments Vari Compressor
- and a multitude of other classic emulators.
A multiband compressor in essence does nothing out of the ordinary. Meaning: it compresses peaks.
But there’s more! The fun and very useful thing indeed about this type of compressor is that it can split the frequency spectrum into different bands and compress those differently. That way, you’re able to control dynamics differently in the low, mids and highs for example.
Now, to be fair,… most of the time, when you’re mixing, you’re not very likely to ever need one. In fact, my advice is always to try and solve every problem you encounter with EQ or regular compression first before you resort to other measures. Most of the problems can be solved with those tools.
If you can’t solve your peaking or transient problems with those, you could try a multiband compressor. But… as I mentioned… you’re just not very likely to ever be in need of one.
When mastering,… That’s a whole other story. But then again, we all know we shouldn’t be mastering our own mixes anyway, right?
If there is any lesson I would like you to remember from this discussion about different types of compressors, it’s that you can and should always use the right tools for the job. Sometimes that will be one compressor, other times that will be another. Learn to use them, listen to their sonic characteristics and try it out!
Thanks again for letting me teach you how to improve your sound!
Kevin – The Soundcoach