Compressors are great helpers to help us maintain the balance of our sound. Depending on how we set it, a compressor can increase the volume of silent notes, decrease the volume of loud notes, or do both simultaneously.
This article is a general compression guide for beginners.
There are expensive studio compressors, affordable compressor pedals, DAW compressor plug-ins, etc. In this article, we will be focusing on simple every day compressor pedals.
Although I am a bass player, the principles in this article can be applied to any instrument.
What Is A Compressor?
“A compressor is basically a pedal to balance the volume of your signal. When a signal is too loud, a compressor limits or squishes this spike to a more reasonable level. When a signal is too soft or starts to fade, a compressor can boost the signal to even out dynamics.” (Reverb)
The terms change from pedal to pedal, but here is a general overview of the controls we have on a typical compressor.
Threshold determines the scope of compression. A low threshold rate means that the compressor will cover silent notes. A high threshold rate means that the compressor will ignore silent notes and focus on louder notes only.
Attack time determines how fast the compressor will react after we play a note exceeding the threshold. A fast attack time means that the compressor will react as soon as it hears the note. A slow attach time means that; after hearing the note, the compressor will let the attack & note ring a little, and activate afterwards.
Release time lets us determine how fast the compressor will deactivate. A fast release time means that, when it hears just a few notes outside of the threshold, the compressor will deactivate itself. A slow release time means that, even after hearing notes outside the threshold, the compressor will stay activate a little longer.
Rate determines the force of compression. 2:1 is a light compression rate of 50%. “It indicates that a signal exceeding the threshold by 2 dB will be attenuated down to 1 dB above the threshold, or a signal exceeding the threshold by 8 dB will be attenuated down to 4 dB above it.” (UAudio) Following the same logic, 4:1 is a medium compression rate, 8:1 is a strong compression rate, 20:1 / ∞:1 can be considered as a brick wall limiter.
How I Use Them
How you would use a compressor depends on your purpose.
One of my purposes is to achieve a constant, ever-flowing bass sound without any volume deviation – imagine typical Muse or electronic bass lines. For this purpose;
- Threshold should be very low, because I want to cover every single note
- Attack time should be fast, because I am aiming at a sustained constant volume; I don’t want any peaks when I attack the strings
- Release time should be slow, because I don’t want to deactivate the compressor due to some silent notes in-between
- Rate can be set medium / high
Another purpose is to use the compressor as a limiter to prevent volume peaks due to technique, slapping or mischievous pedals.
- Threshold should be high, because I’m focusing on volume peaks only
- Attack time should be as fast as possible, because I want to “catch” the peak
- Release time can be relatively fast; because after catching the peak, things can get back to normal
- Rate should be as high as possible, because I’m willing to create a volume cap
Another purpose is to even out the strings and notes on the bass without eating the tone and dynamics too much. For this purpose;
- Threshold should be medium, because I want to keep some of my dynamics
- Attack time should be medium for the same reason
- Release time should be medium for the same reason
- Rate can be low, around 2:1 or 4:1
A compressor is an optional, but very welcome addition to my pedalboard setup. If I have free space, I feel safe having a compressor set to “limiter” mode; and the sound guys enjoy the controlled bass sound.
My compressors of choice can be seen on my bass gear list.