If you're talking about music, bit-perfect, and Windows upsampling everything to 48hz, then it involves a lot of faffing and I dunno if you can even do it on iTunes in the way that you can with say, Foobar2000 or J-River Media and the WASAPI "exclusive mode" plug-in.
You need specific soundcards, that are either good to go out the box or can be flashed with specific drivers at the very least to even get started.
This is why I got a Mac for iTunes since OSX is bit-perfect out the box as long as you leave iTunes volume alone and turn off any of the EQ effects, and can be output either through USB or SPDIF.
If this wasn't about bit-perfect ignore the above lol.