Following Popper's basic tenet in phylosophy of science there is no such thing as "scientific truth". What we have is a collection of "unfalsified hypotheses". When someone succeeds in doing so we have a "paradigm shift" (Thomas Kuhn). (Well, it's a tiny bit more complex, but you get the idea)Of cource not. But. Strictly speaking, talking about science and if we allow us to be somewhat philosophical, nothing can be proved. What we have are hypothesies. We can try to falsify them, but as long as they are not falsified they are the etablished facts. Just claiming ”there is no evidence” for something is not valid as a falsification. If you believe in the exictence of differences in sound quality, which can not be revealed by best practise when it comes to measurements, then to begin with you have to etablish the existence of these differences supportet by an transparent methodology.