Seems there is a whole new hobby of upmixing classic albums (usually from the best vinyl sources, such as Mobile Sound Labs, etc.) to digital DTS 5.1. See this website for more information:
Many people take their resulting efforts and then burn them to DVDs and play them on their DTS enabled Home Theaters. I found a sample on the internet, burned it to DVD and was impressed with the quality of the separation!
However, I am now happy to report that rather than go to the step of burning to DVD, the AppleTV (unhacked even!) will act as a player for these as follows:
Take the raw WAV file and Add it to iTunes.
Convert the file to Apple Lossless (you can now delete the original WAV file; Keep it if you ever want to burn it to DVD - Apple Lossless does not work on DVD)
(optional) add Metadata info and artwork. I NOTE in the file name that this is "(5.1)" and use the category Surround Sound 5.1
Sync to the AppleTV
Connect your AppleTV's optical digital audio port to your DTS enabled Home Theater (I assume you have already done this so that you can watch your AppleTV video content in 5.1 Surround Sound)
Play the music file on your AppleTV: BE SURE that the audio on your TV is turned ALL THE WAY DOWN, as it will interpret the DTS as noise. Turn on the audio in your Home Theater and enjoy sitting in the middle of your music!