@bolong - what you say may well be true, but the basis for determining what sounds realistic to each of us comes from the same sources that create sound waves, which pass through air and into our ears. We may well hear differently, but what we identify as realism is of the same origin. The equipment that reproduces recorded sound waves are thus equally judged from their approximation to those origins. So there is indeed a basis for comparisons we can all share.
In friendship - kevin