Vent Normalization

Vent Normalization makes everybody’s voice volume the exact same volume. In essence, you won't blow your ears out or have difficulty hearing people.

Here's how:

Go to Setup
Enable Direct Sound
Select the SFX Button
Select Compressor and click Add
Under Compressor Properties use the following settings
Gain = Adjust for how loud you want people to be. (I use 7)
Attack = 0.01
Release = Around 500
Threshold = Around -30
Ratio = 100
Pre delay = 4.0

Thanks to Delerious for this guide!