It’s amazing to see how much time one guitar player might spend trying to find that perfect tone. Whether it’s just that part of the song you like or your own musical piece that you’re recording, it’s not unusual to see them sitting next to their amps and pedal boards and playing around with all the knobs for hours. It’s as if the guitar players are ready to spend way more time doing this than actually practicing or learning music theory. After all, your tone is important. However, it seems that many players tend to overlook one of the most important effects that can help you change and improve your tone drastically. We’re talking, of course, about compressor pedals. Although it might seem like an extremely boring pedal, compressor serves its purpose in modern music, not just for guitars but for all the other instruments and even vocals.

But what is a compressor effect? You’ve definitely heard about compression in music, but many guitar players out there seem to be pretty confused about it, not exactly knowing what it actually does, and what its purpose is. Let’s shed some light on the matter.

What is compression?

To put it simply, compression is a dynamic effect that lowers the volume of louder parts and turns up the volume of the more quiet parts. It’s also referred to as dynamic range compression. The compressor pedals basically detect the volume of your signal and can control how quiet or loud the signal gets according to the parameters that you dial in. Using these pedals, or any other compressor formats like rack mounted units or digital plugins, instrumentalists or vocalists basically control the overall dynamics in both live and studio settings.

With compression applied, you’re able to hear quieter parts better while at the same time getting no unwanted clipping or distortion.

NOTE: Dynamic range compression is not to be confused with audio data compression.

Why do some compressor pedals also mention sustain?

Well, that’s because the compression in itself causes sustain as a “byproduct”. Imagine having a slowly fading signal that’s being compressed. By processing it enough, you can prolong the signal and add some sustain to what you’re playing. It’s not exactly as strong as causing feedback by bringing your guitar close to a huge wall of Marshall stacks, but it still does its trick.

Brief history of compression in music

If we’re going to talk about compression in music, we need just a brief history lesson on the matter. Way back in the 1930s and the 1940s, TV and radio broadcasters began using compression in order to have more control over the volume of the speakers’ voices in shows. It was, of course, also used to amplify the audience clapping in studios.

Sometime during the late 1930s, the first commercially produced compressor appeared on the market, called The Western Electric 110A. There were some other products later on, like the Fairchild 660 and the Collins 26C.

 

Image source: americanradiohistory.com

As the years went by and technology advanced rapidly, they became smaller and more compact, eventually appearing in every decent music studio. And, of course, the compressor became available for guitar players in the format of a practically sized stompbox.

In the 21st century, we saw the rise of digital compressors in the form of plugins for DAWs like Cubase, ProTools, and others. With the effect being present everywhere, some have argued that it’s being overused, especially in mainstream pop music. Hearing a song from the 2010s feels very different compared to an average song from back in the 1970s. Even remasters of old songs and albums are being compressed to the point where a lot of the dynamics of the original material are lost. There’s even this thing called “Loudness War” that’s been going on since the invention of compressors. But that’s a whole different topic so we’ll focus on guitar compression (for now).

Basic controls

Every compressor pedal, or a rack-mounted unit, or a digital plugin, have the same basic controls on them. Of course, some are more complex, some are pretty rudimental, but controls serve the same purpose on all of the pedals you’ll find out there.

Volume: Just like on any other pedal, controls the output volume.

Threshold: The essential control for the compressor that tells at which point the signal will be affected. Setting the threshold at the desired level means that everything above that level will be affected. The higher you set the threshold, the less processing will there be involved in your signal.

Ratio: Another essential component, the ratio is used to set how much compression will be applied after your signal passes the threshold. The ratio of 2:1 means that the gain over the threshold is reduced two times. The ratio of 4:1 means that it’s reduced four times, and so on. When ratios are greater, like 15:1 or even 60:1, then the effect is referred to as the “limiter”.

Image source: Wikipedia.org

Attack: The amount of time needed for compression to kick in after signal passing over the threshold. It’s usually measured in milliseconds.

Release: Also measured in milliseconds, the release presents how much time it takes for the compression to stop after the signal goes back under the threshold.

Sustain: You won’t find it on most pedals, but the sustain knob controls this side effect of compression, making your tone last just a bit longer.

Types of compression

It should also be noted that there are two types of compression – upward and downward. The downward compression makes louder parts of the signal over the threshold quieter. The upward compression makes the quiet parts below the threshold louder.

The expander is kind of the opposite of compression, making the quiet parts more quiet and louder parts louder. A standard noise gate pedal is essentially an expander.

What it means for guitar players

Now, you’re probably wondering what this actually does to one’s guitar tone. The compressed tone is often thicker and this has its purpose for both clean and distorted guitars. You know those clean funky tones played on a classic Fender Stratocaster with single coils? Or those huge crushing metal tones that? Both are some of the examples of compression in music.

You’ll most often find compressors used for rhythm parts, where the dynamic range is “trimmed” and doesn’t go out of the desired spectrum. At the same time, compressor pedals can also be used for those louder and distorted lead sounds, essentially serving as boosters that additionally “thicken” your tone.

Being part of the rhythm section, bass players should probably consider having a compressor pedal in their arsenal in order to have more control over their dynamics. As a bassist, you don’t want to suddenly peak in the mix after slapping or hitting a certain note too hard.

Below is an example of how compressed guitars and bass sound like. In fact, there’s a lot of compression going on here, even on the drums. Take a listen:

Being a dynamic effect, compressors are usually placed right before the distortion in the signal chain, after wah pedals and other filters and EQs. Of course, everyone is free to experiment and find what suits them the most in their own style of playing. Experimentation is always welcome.

Why some guitar players don’t like compression

With the already mentioned Loudness War, compression has gotten somewhat of a bad reputation in the last few decades or so. Some guitar players might dislike the effect since it alters the dynamics of their playing. Some players might prefer the old “organic” vintage tone and the freedom to have as much dynamics as they want. Since distortion also adds some compression to the signal, certain guitarists prefer not to use compressor pedals from the fear of losing dynamics even more.

But the thing is – compression serves its purpose and can significantly improve your tone if used properly. Quality compressors will make your tone thicker and fatter, and pedals like the old Boss CS-2 or its newer version CS-3, are often praised for achieving this particular effect more easily.

Examples of compressor pedals for guitar and bass

Now that you’re (hopefully) somewhat informed about compression, maybe you’ll want to go out there and check out some of the compressor pedals. In today’s market, there’s a whole variety of different products that you can choose from. So here are some examples of good compressor pedals that you can find today.