Anyone serious about investigating this subject should download an AB/X comparator program, convert hi-res files to 16/44.1 and then compare them blind to the original hi-res. Use as many samples as you like. Listen as long as you like. Just make sure you don't know if it's the original hi-res or the redbook you're listening to. That will reveal exactly what advantages you hear.
Tim
I am trying another approach.
I recently downloaded (from HD-Tracks), for this very purpose, a hi-rez Diana Krall CD of which I already have the Redbook CD.
I will have my wife do the switching (equipment is in another room) and then I will know if my ears can tell them apart (I sure do WANT their to be a difference which I why I need to do this test --- I'm not objective.)