Robertt8 said:
Man! I REALLY didn't understand all those 99999's and 55555's...now THAT was confusing!

Sorry about that, I was trying to think of a way to relate time and signal level. I'll try to explain it though... With an attack of 5 ms, your signal is going to be un-compressed for that 5 milliseconds, and then the compressor will begin gain reduction by whatever the ratio is set at, so you probably won't hear that too much. But, if you kick up the attack to 15, you have more of a chance of hearing the signal come in strong for a split second before the compressor compresses it because the compressor waits longer to engauge. I'm going to try to explain the logic or thought process of it...

Wish me luck!
Ok, pretend I'm a compressor. I have a signal come in that is rising, and my threshold is set to -20. Once the signal hits -20, I'm going to wait for 5ms(my attack) before I do anything about it leaving it free to go as high as it wants because I want to make sure the signal is going to stay above that long enough for me to do anything. So, after 5 ms, I'm going to turn the gain down (how much is specified by the ratio knob), and I'm going to hold that much gain reduction for however long the release knob tells me.
Ok, that was weird, but may helps? There is no chart that will help you, just some tips and knowledge. I find that knowing WHY something does what it does is the best way to learn how to use it.
Tips: Remember, a compressor will never take a signal LOWER that the threshold (unless you have the release set REALLY long with the ratio cranked). Your signal will always hit full strength for for the length of time that the attack is set for. A compressor set to infinity will cap the signal at the level of the threshold. Geeze...

I should sit down and write a book. lol I'm trying to think of more tips and I'm having a brain fart...
The ratio and the threshold are not tied in any way. The only corolation they have would be if you set the ratio to infinity, then your signal would never go above the level you set the threshold at.