Short Answer:
A compressor effect pedal normalizes signal levels, making louder inputs quieter and quieter inputs louder. Resulting in a distinct audio effect that "rounds out" output levels, compressor guitar pedals assist in normalizing signal levels and enhancing sustain. Guitarists can use compressor pedals to perform fingerpicking more reliably, create lasting note sustain, and get more articulation out of single notes.
Long Answer:
TL; DRCompression is a more specialized effect than your average reverb or distortion. You'll most likely want to use a compressor effect pedal for genres like country or funk where the style of guitar playing benefits specifically from the effect's level-normalizing characteristics.
Compressor effect pedals are among the most misunderstood (or perhaps, not even misunderstood – just not understood at all!) effect pedal types most guitarists will come across. In all honesty, compression is an effect with a pretty high learning curve when compared to a distortion or a delay, so it's all completely warranted. In any case, compressor effect pedals can be as simple or as complex as you can imagine, so let's run down a few real-world use cases and what you can expect out of the sound of a compression effect pedal.
Compression does wonders for any style of guitar playing where you're trying to get a normalized output of many notes being played. Think of country guitar-style fingerpicking where things can get fast and furious pretty quickly with a storm of single notes flying at you. This kind of clean, fast, articulate riffage will want every note to be heard, as you'd usually want every note in your scale to be audible. This is where a compressor will come in to boost notes that may have missed a precise pluck and quiet notes down that got hit a little too hard.
Probably the most prominent tonal characteristic you'll get out of a compressor effect pedal is a round, soft, "poppy" sheen around your sound. This just comes from the compressor effect act work, where it keeps up with your signal in adjusting its ever-changing level.
A few trusty compressor guitar pedals you can turn to for a variety of different compression effect experiences include:
- Boss CS-3 Compression Sustainer Effect Pedal
- Universal Audio 1176 Studio Compressor Effect Pedal
- JHS Whitey Tighty Mini Compressor Effect Pedal
- Keeley Electronics Compressor Plus Compressor Effect Pedal
- Heather Brown Electronicals Darlene Compressor Effect Pedal
- Origin Effects Cali'76 Stacked Compressor Effect Pedal
- MXR Dyna Comp Compressor Effect Pedal
