This version of Doom 3 for Mac has a preview for use of OpenAL technology enabling surround sound support...... if you have such a soundcard. I tried to get it working using the Optical Digital Audio out connected to my Logitech Z-680 speaker system. That won't work. I assume the decoding of the 5.1 audio has to happen on the Mac (i.e. the Dolby 5.1. sound card like on a PC)? You can download it here Anyone tried it?