Best Compressor Pedals
What is compression?
To get to the bottom of this, we first need to understand what compression is. If you’re an electric guitar player, or a bass guitar player, you’ve most likely seen compression pedals or rack-mounted compression effect units. While the word “compression” has widespread use in many different fields, there are two things it can mean in the world of music. One is audio data compression that deals with the data storage of digital formats. The other type of compression and the one we’re interested in is dynamic range compression. Obviously, we don’t want to compress the audio quality, but rather control our dynamic output, so make sure not to confuse these two types of compression in music.
Physical compressor units or software plugins detect the strength of your guitar’s signal, control the overall volume and determine how loud or quiet your output will get, all according to the desired parameters. But this is not like your regular volume pedal or volume control. Basically, compression “evens out” the volume by making louder parts quieter and quiet parts louder. Here’s a video from Paul Davids that digs deeper into compression.
How does it work?
Any compressor pedal or other physical or digital version of the processing unit does roughly the same thing. Some of them may have fewer controls, which can be the case with some simplified pedals, like the MXR M102 Dyna Comp. But all compressors take the signal, “recognize” the louder and quieter parts and sort them out according to parameters. We’ll explain how the effect works through these main parameters – threshold, attack, release, and ratio.
The threshold sets the point where the compressor effect will kick in. It’s basically the volume above and/or below which the signal will get processed. The higher you set this setting, the more your signal will be affected, and this compressed.
Then we have the ratio, which determines how much the signal will get compressed after it passes over the set threshold. It can be represented numerically. For instance, when the control is set to the minimum, the ratio is 1:1, which means the signal past the threshold is not affected at all. Now here’s the important part – if the ratio is 2:1, the gain is reduced two times above the set threshold. If it’s 3:1, then it’s reduced three times, if it’s 4:1 then it’s reduced four times, and so on.
Attack and release are kind of similar to parameters found on other effects. Attack represents the amount of time, expressed in milliseconds that it takes for the compression to kick in after the signal gets over the set threshold. The release is the opposite and presents the amount of time in milliseconds it takes for the compression to stop after the signal gets back in the set threshold limits. While attack and release have their purpose, they’re not that often present on compressor pedals for guitars. Some may only have “attack” knob, while others (like Fender The Bends) will have the so-called “recovery” knob that controls both attack and release.
Almost all compressor pedals have a volume knob. This way, you can control the overall output volume of the altered signal. So you get your tone dynamically compressed, everything is evened out, and then you set whether you want to make this processed signal louder or quieter.
Many of the manufacturers these days began introducing the “blend” control. Similar to the “mix” or “dry/wet” controls of other effects (like delays, reverbs, or choruses), the blend knob controls the ratio between processed and unprocessed signals. It’s a very useful feature that gives a lot of versatility.
In some cases, we can also find the tone control that can help you add more high-end or bottom-end to your tone. It’s not that common and it’s not essential, but it offers more functionality in the process of tone shaping.
Why are some pedals also called “sustainers”?
The true sustain usually comes down to the type of instrument that you’re using and its pickups. However, guitar players can get more sustain as a “side effect” of compression. By amplifying the quiet parts, a compression pedal can prolong the signal while it’s slowly fading out. This is why some of the pedals can have an additional “sustain” knob. It’s not like it can significantly add more sustain to your tone, but it does help in some cases.
Different types of compression
As we said, compression works both ways – it increases those quieter parts and brings down the loud parts. With this in mind, we have the so-called “downward” compression, which reduces the gain of loud parts of the signal, and “upward” compression, which increases the gain of quiet parts.
Compressor pedals do both of these types of compression at the same time by setting both the low and high threshold. Everything below and above these two set limits gets processed.
Keep in mind though, while the cheaper guitar pedals produce top-quality sound, you will want to get up to premium prices if you want that true professional sound.
If you’ve been lurking online or visiting guitar stores a lot, there’s a high chance you saw “limiter” pedals. The limiter is actually a type of compression with extremely high ratios. There’s no real consensus on the exact ratio, but anything that’s above 10:1 or 15:1 is referred to as limiting. In some cases, these ratios can be as high as 60:1. This type of compression is most often used for bass guitars and synths, while it’s not that common for regular guitars.
Implementation and importance
The compression effect can come really in handy for many different musical styles and various settings. Over the years, it found its use both for clean and distorted tones. The whole of compression is the overall dynamic control. In any band or orchestra setting, a guitar player would always need to find ways to sort out their dynamic output. For instance, when the guitarist is doing all the rhythm parts, there shouldn’t be any sudden dynamical bursts. While you can have a volume pedal, the overall control without compression is very difficult. The guitar can sometimes stand out in the mix and make it more difficult for the singer or any lead instrument to do their thing.
And this is especially the case with bass guitars that can suddenly pop out with brief bursts of volume, especially when slapping technique is applied. A simple compressor pedal or a limiter can solve this issue, while still keeping all the desired tonal properties of the instrument and the “twangy” sound the slapping produces.
If we’re talking about rhythm guitar sections, many funk guitar players use compression to keep things in order with their sparkly-sounding single-coil pickups. In addition, the tone will get slightly “scooped” with an additional boost to lower-end.
Compressors are also useful to make your tone more “thicker.” If you have a guitar with single-coil pickups and you need to make it sound closer to the tone of humbuckers with distortion, the effect these pedals produce can help you enhance your overall output.
Another setting where compressor pedals come in handy is for distorted rhythm tones in hard rock or heavy metal. By squashing the dynamics a little, the rhythm guitar gives more room for other instruments to cut through the mix.
It’s not unusual to see compressor pedals turned on for lead sections. After balancing the tone’s dynamics, the volume knob on the compressor can be pushed up to boost the overall output. Some high gain lead sections require this kind of a tone where the guitar won’t have much of dynamic fluctuations. In some cases, compressors serve their purpose as simple, clean boosters, especially for guitar players who like to push their clean tube amps over the limits and get that “organic” distortion from them.
However, you should be careful when using compression with distortion, mostly because distortion itself adds some compression to the tone. Not every type of pedal works the same, though, so you’ll need to do some testing and tweaking in your setup to find what works best for your choice of compressor and distortion pedals.
Why is it so overlooked?
The reason why this effect gets so overlooked is due to the fact that less experienced guitar players don’t completely understand how it works. And even when they find out what it actually does, it takes a lot of time to learn how to implement it in the band settings properly. What’s more, the real impact can be heard only in a band setting, and not when you’re jamming at home on your own.
In some cases, it’s just a force of habit, and players would rather spend their money on this wacky chorus effect. However, no matter how boring or uninteresting compressor pedals might be, they can do wonders to your tone. And, most importantly, the audience notices when the dynamic output is sorted out.
Is it true that even some experienced guitar players don’t like compression?
Look, compression is not mandatory. There are plenty of different musical styles and settings where the effect might not work that well. For instance, many of the vintage-oriented blues, jazz, or blues-rock players like to use the full potential of their dynamically responsive tube amplifiers. In these settings, even the slightest nuances in dynamics during a solo can mean a world of difference. So it’s not unusual to have some old school players relying on simpler settings where there’s no compression involved.
There’s also the opposite of compression…
While we have compression, there is also a completely opposite effect, commonly referred to as “expansion.” We already explained how compressors turn up the gain below the lower threshold and bring it down above the higher threshold. Well, the expander sets the threshold but makes quiet parts quieter and loud parts louder. This type of effect is used for filtering out unwanted noise, and these pedals are known as “noise gates.”