You don't say what type of Mac you have. You have to have a Mac that has built in support for optical digital audio output for the support in Panther to work and of course an appropriate set of speakers.
DTS is standard on virtually all AV amps, use one of these and buy youself a good set of speakers, you don't need massive speakers in a bedroom esp if your going to be sitting very close to them.
Strangely I was fixing that as you were typing it seems, now I should change it back to keep the joke... 😀
QuickTime will not play DTS or AC3 files from a file, only the DVD player will decode and play those, althought the DVD player will play both from a VIDEO_TS folder.