Compression decoded plz?

So lately I've been thinking while using some comp plugins, what do these terms actually mean?

Threshold

knees

ratio

lookahead

side chaim

Threshold is how quite or loud the signal will get before the compressor starts doing its thing. I'm not sure on the others

pardon me for being a dick about this, but compression and expansion is pretty complicated when compared with their cousin limiting and gating.... all these parameters can effect eachother... for instance the function of the threshold control changes based on the knee and ratio.... you should read about this in one of those informational thingies that educated kids before the internet.... umm, what do they call them? BOOKS!

but if you don't want to buy a book on audio engineering basics then just do a google search and find a good basic article but NOT a "for dummies" article. I could run through this for you as best as possible but just because I know exactly how all these controls interact and what they are meant to do doesn't mean I can define and explain them as well as a an experienced guy with experience as a technical writer and/or educator.

Compressors as a pre-amplifier effect or in an effects loop can be cool for country chickin' pickin', fingerpicking of all sorts and as a clean lead boost that can alter your attack and decay characteristics. But they are mainly just a source of noise, tonal coloring, etc... most guitar compressor pedals (like the ross and dynacomp), even the ones with a lot of knobs (wampler and keeley), have a lot of the functions you are questioning preset or buried inside the PCB on trim pots. They also are mainly based around a really primitive and lofi design from the early days of radio and lack a lot of the pizzaz of sharp-cutoff tube and opto designs as well as being less transparent and tweakable than dbx types of VCA designs... I thik only a few companies make studio-grade compressors for guitar level signals in and out and some are better than others. All of them are costly though. Most affordable studio compressors are line level and can only be sued with your effects loop when its set to line, though INTERESTING results could be achieved by running your guitar into a studio compressor via a DI or mic preamp's HI-Z input and then using the hot, lowimpedance line level output to slam the front of your guitar amp.... of course, once youa re pummeling the 1st gain stage it can defeat some of the point of compressing the signal because one of the main artifacts of overloading a tube besides harmonic distortion is compression prior to full-on square wave clipping (essentially limiting with huge amounts of distortion)...

man, I am probably confusing you. Read up.