Honestly, Compression can really help you out sometimes...but i stay away from it as much as possible...I dont think music is supposed to sound "squashed"...its supposed to sound tha way it sounds...so i use minimal compression...
In general, you can Limit, or Maximize/amplify a sound with compression...depending on tha ratio, threshold, etc that you use...I use compression sometimes when i have a bass drum that confilcts with my bass line and in return creates clipping or distortion...in this case i can compress my kick, and maybe even my bass (if needed) and then it wont peak...tha levels will just have to come up a tad instead to be around tha same decibles it was before....But no more clipping usually happens after compression if doen correctly...
Note: if you ever hear a "ducking" sound that probably means that you dont have tha knobs in tha right place for what your trying to do....i usually just feel it out...I would try reading a little jus about how compression works to help better understand what those dam knobs do...Im not tha biggest help when it comes to tha mathmatical shit ya know?
wait...
i just found some stuff i saved a long time ago...
READ THIS:
Ratio
The ratio sets the amount of compression that is being applied when the treshold level is being reached. The settings are set in ratio's like 8:1.
When there is 8db of signal going over the treshold level this will be reduced to 1db when using this setting. So 8db over the treshold level becomes 1db over the treshold level.
The ratio is very important coss it sets the power of the compressor. If you want to use the compressor as a limiter you should set the ratio to full. Preferably infinite:1 but since the Reason compressor doesn't have this setting 16:1 will do. This will prevent most incoming signals to get past the treshold level.
Treshold
This is the level at wich compression will set in. If a signal doesn't pass this level the compressor won't touch it. But if it does exceed the treshold level compression with the power of the ratio will be applied.
Attack
The attack sets the time it takes for the compressor to set in after the treshold level has been reached. If this is set to 0 the compressor will directly work when any signal is passing the treshold level. But if set higher it will gradually set in after the treshold level has been reached. This is useful if you want to maintain the initial attack of the sound you are compressing.
Release
The release sets the time it takes for the signal to get back to it's original level after it has dropped below the treshold level.
If you want to have your compressor to pump up your sound you need to set a fast release. Now pull down your treshold untill you reach the desired effect without clipping. If you haven't reached the amount of 'pump' you like but the signal is already clipping you should set your ratio higher. In this case you could also set your attack faster to get to the loud unprocessed attack earlier.
On the Reason compressor there's also a gain reduction meter on wich you can see how many db reduction you have. If this is to high you have the chance of noise getting to loud and you will definately have no dynamics anymore in your sound.
Compression is really important in a composition. It's not for nothing that all the big studio's have racks full of these devices. It's also advisable to add compression to all your devices actually. Not only will you have full control over levels but the sounds will be also better to mix together.
When you are using a compressor to even out your final mix you better not use extreme settings coss this will result in parts that should be in a low volume to rise and parts that should be loud to drop. You should search for a balance between those two. When compressing a mix there are certain to look out for. When you set your treshold level below the level of you bassdrum this will cause the bassdrum to make the rest of the mix also softer. So you can imagine what will happen then. After each kick the mix will drop resulting in a weird sounding bouncing situation wich nobody would wish for to happen with his track. So you have to make sure that the treshold level is set above the level of your bassdrum.
And this goes for all sounds actualy. If they appear regularly in your mix then the treshold level can't be set under that level or otherwise that sound will control the compressor leaving the mix to be pulled down in volume.
Here are some settings wich can make sounds nicer. Note that these sttings are a guideline and must still be tweaked to suit your sounds perfectly.
Kick:
Ratio: 105
Treshold: 85
Attack: 20
Release: 40
Snare:
Ratio: 105
Treshold: 80
Attack: 30
Release: 20
Bass:
Ratio: 103
Treshold: 40
Attack: 35
Release: 60
When you use a compressor you should try various settings because every sound is different and so it needs different compressor settings. These settings are however nice guidelines wich will help you in the right direction i hope
Steezo