Your definition of CI is worded better than mine. It's what I had in mind, but didn't say as well.\nI've had lot's of experience in lab biochemistry and molecular biology, but very little experience in blind listening tests. Just once I participated in one where about 40 DIY speaker builders listened, while blind, to speakers with crossovers made with either cheap non-polar electrolytic capacitors or expensive film-type capacitors. No one in the group could reliably identify them by listening. Overall, the group's average was 50% right answers and 50% wrong, no different from random guessing. The conclusion was that people could not hear differences in sound due to different crossover capacitors.\n\nImportantly, no controls were done in that test. Dennis Murphy, one of the organizers of the test, told me at the time that doing controls like that would consume a lot of time & effort. Time & effort that he preferred to spend on testing different capacitors.\n\nA raging debate soon broke out, challenging the test results. All the usual arguments were invoked about how the test couldn't have been sensitive enough to detect the subtle, unmeasurable, differences made by different capacitors. A simple negative control could have argued strongly against those non-believers' points. Not long afterwards, Dennis admitted to me that he wished he had done that negative control.\n\nIncluding appropriate negative and positive controls with experiments was an important part of my scientific education, in grad school and beyond. Every one had to learn the hard way that publishing anything required good controls. And figuring out what they should be was the hardest part of doing science.\n\n\nHaving worked in the consumer audio business for over 40 years, I still have to wonder about the reasons for choosing equipment. At some point, wasn't it about listening to music and other source material? What happened to that, as the main goal? \n\nTrying to find the absolute best equipment and accessories is a good way to go broke and end up extremely frustrated unless they happen to find things that work well together and their room is fairly acoustically neutral, by design or coincidence.\n\nI don't have a problem with searching for 'better', but 'best' is very similar to 'perfect', which is impossible. 'Best' means that nothing is better than the item in question.