The simplest way to put it is that I'm interested in comparing an actual digital master - no tape involved - the unaltered final product that the engineer keeps as their defacto master. Then comparing that to the standard CD or mp3 version. There are a few mastering engineers that have these available for purchase. Get it? EDIT: It's not a silly debate of "oh 24-bit, DSD blah-blah" malarkey. Just something that is an unaltered digital-origin original vs whatever format that is different from it. Is it not something that could provide some significance somehow?