Well, let's not compare science with pseudo scientific claims from the audiophile community. The idea that DAC differences aren't measurable isn't coming from the scientific community. Just because some people "theorize" that anal probe alien abductions are real, doesn't mean we should put any stock in it. Then I don't understand the sweeping generalization about expectation bias. For instance, you should know that volume differences can affect perceived differences in listening tests. It's not all about expectation bias.