For Mac users to be able to communicate in your Ventrilo server you will need to change the server codec to the Speex codec such as, Speex (32 KHz, 16 bit, 10 Qlty).
You are able to set the server codec from the provided server control-panel.
To change your server codec follow these steps;
1.) Login to the web control-panel, http://control.branzone.com
2.) Browse to; Voice Servers > YOUR_SERVER > Voice Server Configuration
3.) Once in the configuration page select to edit the "ventrilo_srv.ini" file.
You will then see the option to change your codec at the bottom of the options page. Once you have saved the changes you will need to restart your server.