[Answered] prochannel compressors affecting volume (x3e)

Spencer
Ah, I see. Indeed the default 5:0 ratio is causing that behavior. Lowering it to 1 and the peak stays the same. It's weird to me, I've never seen a compressor act on the signal with no threshold at all before; much less actually boost it by raising the ratio only. Some form of integrated auto-makeup gain perhaps. 

 
No, simply that controls on a compressor interact. The ratio and knee both affect the threshold, unless the knee is hard. So you can set the threshold to 0, but other controls may move it off that value. 

You can see this easily if you call up the Sonitus compressor. Set the threshold to zero and vary the ratio. The only time the ratio won't interact with the threshold is if the knee is hard. The higher the knee setting, the greater the degree of interaction.
 
A simple analogy is an amplifier with an input and output level control. You can set the output for 0, but if you alter the input, you can get more or less level appearing at the output without changing the output setting.
 

And then there's the 76 doing the opposite, decreasing the gain with just a step up in ratio, until you reach 20 which seems to put the level roughly back where it was on the 4, then the 100 which is the loudest of all; all of this with 0.0 input and output. Quirky stuff if you ask me.

 
The "100" is not 100, but the symbol for infinity so it is acting like a limiter instead of a compressor. The PC version models the original quite accurately, which people expect if they've used a real 76. That's considered part of the unit's "charm." I personally don't have a problem if companies want to take liberties with a model and clean up the oddities. But purists would scream...I asked Waves once why they included a switch on their Aphex Aural Exciter module to add the hum and noise of the original, which made no sense to me. They said in listening tests, people who had used the hardware version said the plug-in didn't sound "right" without the added hum and noise. 
 
If you want a "classical" compressor that doesn't try to model a physical unit, use the Sonitus but make sure "Type" is set to "normal" and not "vintage."