I have been looking everywhere for days trying to figure this out... I am a total OSX noob but I was able to search and find that I should go under Applications > Utilities > Audio Midi Setup to configure the output. I set it up for 5.1 surround and tested each of the speakers and they work. However, if I try to play a DVD movie either directly off the disc or an MKV that I've encoded I always only get sound from my front speakers. I've tried a bunch of different DVDs and MKV files and a bunch of different programs including the built in DVD player, Front Row, Plex, and VLC Player. I should mention that I am running the HDMI from my Mac Mini directly to my receiver. And like I said, when I tested the speakers under Audio Midi Setup they were working properly. I've even checked the options for the various programs and made adjustments when possible. Still no luck.... Can anyone with the new mini and a similar setup that has had success give me some tips or point me in the right direction? Thanks. Also my apologies if this has been answered before, I did a few searches but I couldn't find anything that answered this particular question.