Hey found this in the WoW main forums.  May help us who have problems with people's vent levels.

Original link [url]http://forums.worldofwarcraft.com/thread.html?topicId=112501444&amp;sid=1[/url]


 Vent Normalization makes every bodies voice the exact same volume. In essence, you won't blow your ear's out or have difficulty hearing people.
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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 15)

- Attack = 0.01

- Release = Around 500

- Threshold = Around -30

- Ratio = 100

- Pre delay = 4.0