Of all the pedals that go on a pedal board, none are shrouded in mystery more than the compressor pedal. For some, it’s an essential element to their tone, for others, it controls their dynamics and sustain, for rest of us it might as well have a question mark screen-printed on it. What we’re going to do in this blog entry is shed a little light on the compressor pedal, what it does, and how to use it properly to get the most out of it. Stick around, you might find it’s the pedal you been missing this whole time.
A Brief History
Originally used for broadcast radio, the compressor/limiter was designed to keep the dynamic range of a broadcasted signal under control by preventing overmodulation A.K.A. distortion. It was then adapted to be used in recording studios as a means to make the recording engineer’s job much easier by freeing him/her away from the meticulous task of riding the fader in real time during recording sessions. It was also at this time that compressors were found to be very useful as an effect on individual instruments. Flash forward to today, compressor pedals are a widely used and popular pedal effect for nearly every member of the band.
How Does a Compressor Work?
A compressor is a straightforward effect as its purpose is primarily to level out your audio signal without creating distortion. In the recording world, compression is an incredibly important tool as it will help to prevent digital clipping (distortion), which is as appealing as nails on a chalkboard. Another term you may hear used from time to time to describe this effect is “gain reduction”.
The way that a compressor levels out the audio signal is by making use of two main parameters, threshold and ratio. The threshold sets the audible level at which the compressor effect kicks in. Think of this as an audio ceiling of sorts. The ratio sets the amount of gain reduction once the audio signal reaches the threshold point.
Now, most compressor pedals don’t include these two parameters as separate knobs. Rather, pedal manufacturers will opt for a far easier solution by combining these two parameters into a single knob that they will call “compression”. That’s to make it easier for you as the player to digest so you can easily dial in a sound that you want.
Finally, there are additional knobs that you’ll find on most compressor pedals, including gain, which can be used to clean boost your guitar or bass; tone for adjusting the frequency of the compressed signal; and on some pedals, attack and sustain knobs will be included so you can set how fast the compression effect kicks in and for how long.
What’s the Benefit?
To put it simply, the two main benefits to compression are dynamics and sustain. These are two key words that just about any guitarist or bassist can identify with, as we’re all chasing that dragon sooner or later. With a good compressor, your funk lines become punchy and clean, your solos will sing with sustain, your fingerpicking will pop out of the mix, etc. The benefits are virtually endless.
To prove my point, here are some quick examples.
First, a single chords without compression.
Now here's that same chord with a light compression and boosted tone. Note how long it sustains.
Now, here's a Rock and Rock Rhythm without compression.
And here's the same rhythm with a heavier compression, quick attack, and boosted tone. Note how much more punch is heard in the picking portion of the rhythm.
And finally a funk chord line without compression.
And the same line with a heavy compression, tight attack, and boosted tone. Like the RnR example from before, it's heavy and prickly in nature, which compliments the funk style.
While not as flashy as the distortions, delays, and reverbs of the pedal world, the compressor pedal deserves a spot on your pedalboard. And as there are so many different ones to choose from these days, you couldn’t be in a better place to start looking and listening.