Well, technically... 64bit has less rounding errors (the whole point of it), which means less noise (right?)... which means, someone with golden ears and great system/room COULD hear it. In my book, examples for golden ears are Hans Zimmer and Eric Persing of which both are claiming PT sounds the best, Logic the worst. I tried comparing Cubase and PT HD Native on my Win machine, couldn't hear any difference... maybe PT on Mac sounds better? :D ... maybe PT with 32bit floating point math sounds the same as Cubase and the old PT with fixed point actually sounded better.. i dunno and I certainly haven't done any meaningful testing, but how I look at this is - I believe HZ, Eric and others until I prove myself they are wrong.