that doesn't matter so much... if you are talking about a DVD-A or a SACD, those are mutichannel sources. so that would make things change. but going specifically from a 2 channel CD to a 2 channel DVD. the DVD will hold more information, so should "sound" better because there is more data, so the digital to analog converters in your receiver can make the digital signal much more closely resemble an analog signal.

This is why people still like records, its an analog source, to and analog output...
at the end of the day, our eyes and ears work in an analog environment, so anything digital HAS to be converted to analog for the human body to be able to interoperate it..

i don't know if this explanation helps any or not. hopefully it does.