Confirmed, Vent devs for Mac are still asleep. The following forum post is our only work around without using more 3rd party apps or outboard compressors/limiters before your headphones/speakers. The later is totally possible, but complete overkill of course.
"MAC users cannot do normalization this way. I use a mac and it was frustrating until I figure out I could set up special effects to change the volume of each person individually (and it saves between uses).
To set up a special effect for a person: Right click on the user's name, select miscellaneous, then Special effects. This gives you a slide bar where the volume is set at 100% Move it above 100 for higher volume, below to dial it down a bit."
For those who care, technically Normalization and Compression or completely different. Normalization increases the highest peak to 0 db (or another predefined highest level) where as audio Compression* actually lowers the audio peaks to smooth out the difference between loud and soft passages. So technically the PC suggestion is Compressing Vent, but everywhere I found on the net (including Wow Insider) calls this process "Normalizing Vent". It's still a great suggestion though Forb

*Dynamic Compression like this is completely different from MP3, AAC, etc compression codecs that shrink data size of audio files.
erm....where am I? How did I get here? Sorry about that. Most everyone knows this stuff and apologies for the tangent if you made it this far.