Home Studio Compressor parameters

you are correct that the INPUT GAIN control will increase the amount of signal which gets compressed.  what that means is that all dynamic levels of the signal you are compressing is now higher than before you changed the input gain and that means that the settings you have on the compressor are simply compressing the higher input signal.

if you increase the input gain, however, that will increase the lowest points of the signal which means the threshold will kick in sooner than it would have for a lower input.  It also means that the compression set by the ratio will compress harder for a signal that is already hotter.

so yes, the compressor will work harder to compress the input signal if it has increased from before.

"seem to feel the levels go up" - no disrespect intended - but that's your perception about the way it sounds, it's not based on analysis of the signal.  what really is happening when you increase the gain with the other compressor settings staying the same is that you are actually increasing the overall RMS when it it output.  so the output signal is more compressed than it was before you increased the input gain, but the overall RMS has also increased because of the input being increased.

ok - now the real question: 
Im trying to get the quiet parts of my track to increase in volume is this the setting that does this?
yes and no.  you can increase the quiet parts by increasing the input gain, but that is not ALL that increasing the input gain does (as I explained above, hopefully to your satisfaction).

you'd have to increase the input gain and change the threshold (as a minimum) in order to affect only the quiet parts without increasing the overall rms output.  reducing the output gain will also help with this but all that is really doing is acting as a volume slider for the output.

so if it were my track and I were trying to increase the volume of the low parts then yes, I'd increase the input gain and I'd probably reduce the output gain and increase the threshold and maybe adjust the ratio depending on the way it sounds when those are done. 

that's because the ratio might need to be adjusted because the dynamics are changing due to the threshold changing!

make sense enough?

and finally to answer your last question:
does .01 stand for 1 millisecond on this compressor?

no, for one thing 1 millisecond = 0.001 seconds, not 0.01 (that's 10 milliseconds)

for attack and release, yes, it should be 0.01 = 10milliseconds.

for the other settings, they're in decibels (dB) well, except for the ratio which is just a simple ratio, no units.

hope that helps!

2) yes and no.  it's not a linear relationship, tho.  increasing the input gain by 1dB and decreasing the threshold by 1dB will not give you the same output.  there will still be a difference between the two settings.  and I can't give you specifics on HOW to obtain the exact same output after you've increased the input because part of it is going to depend on the programming algorithms of the particular software FX you are using.  the other variables are due to the ratio - which gives you a 4:1 or whatever setting you're using as a multiplier.  and plus your sampling rate will have a SMALL amount of affect on it - it would be complicated to try to explain why and thus your attack will have a SMALL amount of affect on it as well due to when the samples fall.

3) if you do what you're describing here you shouldn't have a problem doing it, but the result is that you will be compressing heavier than when the input gain was -1dB lower.  adjusting your input gain by 1dB is not going to affect the output by a LOT, but it will adjust the overall rms a little and it will compress just a little more so that the quieter parts will be louder, but the louder parts will not be louder than they were before you adjusted the input gain.