Compressor settings for clean, country and solos

What the knobs do

Sensitivity, Sustain, Compression and Threshold all set how much the pedal compresses. MXR describes the Dyna Comp's Sensitivity knob as setting the compression ratio. BOSS says that turning the CS-3's Sustain clockwise lengthens the sustain, and that turned counterclockwise it limits the output, so the pedal works as a limiter that only stops the loudest peaks.

Output, Level and Volume set the level after compression. Compression turns the signal down, so this usually ends up higher than you expect. Set it where the pedal is no louder or quieter than bypass, or it will fool you into hearing a louder sound as a better one.

Attack sets how quickly the compression takes hold of a note. Let the pick attack through and each note stays defined; clamp it and the notes flatten into each other. BOSS's manual says that with the CS-3's Attack turned clockwise the attack is kept in each note even when you pick fast. The Dyna Comp has no attack knob: MXR lists a fixed attack of 5 ms and a release of 1 second.

Some compressors add a Blend or Mix knob, which mixes the uncompressed guitar back in. The dry signal keeps the pick attack while the compressed one supplies the sustain.

Clean and rhythm settings

For clean rhythm, keep the compression light: sensitivity or sustain between 9 and 11 o'clock and the output at unity. The aim is to catch the loudest strums so the part sits at one level, not to flatten every note. If the chords stop responding when you dig in, back the compression off.

Strummed and fingerpicked parts both benefit, because the pedal evens out the difference between loud and soft strings and between one finger and the next. A clean tone gains more from a compressor than a distorted one does, since distortion already evens the level out.

Country picking

MXR sells the Dyna Comp as a Nashville studio standard, and its Nashville sample setting puts Sensitivity a little below noon with the Output well up, around 3 o'clock. That squeezes each note enough that fast single-note lines come out even, while the raised output makes up for what the compression takes away.

For more snap on each note, use a compressor with an attack control and set it to keep the pick attack, clockwise on a CS-3, so the click of the pick comes through before the note is levelled. MXR's New Wave Squash sample goes the other way, with Sensitivity at about 1 o'clock, for a sound where the squash is part of the effect.

Sustain for solos and slide

For a lead that holds, turn the compression up and put the compressor before the drive. David Gilmour's Comfortably Numb solos ran an MXR Dyna Comp into a Big Muff and a Hiwatt, with the gain shared between the three rather than one knob turned to the top. MXR's sample setting for bottleneck slide has the Output and Sensitivity both nearly all the way up.

High sustain settings raise noise. BOSS warns that as the CS-3's Sustain goes clockwise you may hear noise or howling, and says to turn it back slightly if you do. Turn the guitar's volume down between phrases, or use a noise gate after the drive.

Where the compressor goes

Usually first, or straight after a tuner: before any drive pedal. A compressor reacts to how hard you pick, and it reads that most reliably from the plain guitar signal. The drive then gets a steadier signal, which is part of why a compressor in front of it lengthens a lead.

After a drive pedal it has little left to do, because the distortion has already compressed the signal, and it raises the noise the drive made. Some players put one at the very end of the chain as a limiter, to catch volume jumps between sounds, which is a level job rather than a tone one.

Compressors with high gain

A high-gain amp or pedal already compresses the signal hard, which is part of why a metal lead sustains without help. A compressor in front of it adds little except noise. The usual pedal in that spot is a boost or overdrive, set to tighten the low end rather than add gain.

Where a compressor does help in heavy music is on the clean and crunch parts, where the amp has not already levelled everything.

Acoustic guitar and bass

Acoustic guitar wants lighter settings than electric. The pick attack and the resonance of the body are most of the sound, and heavy compression flattens both, so catch only the loudest strums.

Bass players use compressors more than guitarists, to even out plucked notes that vary a lot in level from string to string. The order of work is the same: output at unity, compression up until the notes even out, then stop.

Compressor settings for one song on your amp

These positions are starting points for the pedal. The amp after it decides how the compression lands, so the same setting sounds different into a clean Fender and a crunchy Marshall. When you want one song's whole chain set for the amp you own, Tonelify works out the positions for that rig, compressor included.