I use a cheap 5.1 Digital-to-Analog Converter
to run audio from my Apple TV 3 to the Zone 2 of my R-972. Works remarkably well and it's the cheapest 5.1 capable downconverter I have found.
There is a Gefen version
, for more than double the price, seems to use pretty much the same internals (but it's on the up and up and it pays licensing fees to Dolby, as evidenced by the logo).
If you are not using a 5.1 source, you can look at something like a simple FiiO D3 converter
Do pay attention to the 2-channel-PCM or multichannel DTS/DD distinction, as from something like the FiiO you'll just get silence from multichannel media feeds.Edited by Ryan1 - 7/3/13 at 6:49pm