I often think science is kind of hard and doing science-like things are kind of beyond my purview, so, again, I leave it to the experts.
nothing wrong with that. there is a massive misunderstanding in the audio community that we're trying to force everybody to blind test everything. it isn't true and for the most part, we really couldn't care less that someone test things or goes with his guts when in the comfort of his home or when sharing his personal preferences. we jump on
people making claims and tell them to properly demonstrate their claims(even more so if the claim happens to be something we doubt). the act of coming to this forum telling people "I can fly and I can notice the change in soundstage when my copper cable isn't really 99.999999 oxygen free", will logically trigger a reply along the line of "pic or it didn't happen". we very much doubt the claim and wish to see proof of it, not really an extraordinary response to some noname dude on the web making a surprising claim. for claims of hearing something special, a controlled listening test is the best, most straightforward method to demonstrate the claim, so we bring that up.
but all this time it is very important to remember that the trigger was some dude making an empty claim on the forum. when someone goes "I like that cable", I won't ask him to prove that he has a subjective preference. that would be pretty dumb. but if he develops and says "because the silver really opens up the soundstage", now of course I'm triggered. can silver "open up the soundstage"? what does that even mean? how could he possibly know that the silver is the cause for his impression? I want answers and if the guy doesn't have them, I'm going to be pissed that he dared make such a claim out of nowhere.
otherwise you can claim that you love Beethoven but only as trap remix, and while some may not agree with your taste, nobody is going to ask you to prove it. (now that I've said it, someone might for the lolz, I'm decline all responsibility)
in audacity you find "invert" in the "effect" list at the top. you do that to one of the tracks, then mix the 2 and if they were very carefully aligned in time and were essentially the same, the result will be nothing or close to nothing. null test is kind of the easiest sort of test but also the most hardcore when it comes to demonstrating inaudibility. because if you end up with almost nothing in a null test you know that almost nothing is different, and of course that's not going to sound like anything. but on the other hand, you can end up with some pretty big stuff in a null test and still not be able to notice the difference in a blind test. the most obvious example would be out of phase tracks(we assume you have aligned them but some frequencies may have a different shift). people are really not that sensitive to phase shifts(unless it's a shift between ears), but if the shift between tracks you null, causes a frequency to shift to opposite phase, you're going to to have signals that add up and the null will show some loud stuff remaining. so it's sort of the opposite of an abx test, with a null you can sometimes prove without a doubt that there is simply nothing different to be heard, but you might not always be clear if an existing difference is audible. while with the abx test, you can prove that you can hear the difference, but you can never prove that there is no audible difference between the tracks. ^_^
different tools do different things. the very obvious example where a null test is the wrong tool, is if used on lossy formats. the remaining signal is always going to significant and audible as a standalone file, because it's signal that was supposed to be masked by the rest of the music. we removed the rest of the music, we removed the mask and lost the very function of that encoding.
I think one of my main points is that I wonder if hearing and perception (and our biases) are really separable?
it's all really just a matter of properly defining something and then sticking to it. if a guy goes to say that X sound different from Y in such and such ways, he very much implies that the differences are in the sound and he can perceive them with his ears. if some of those impressions were caused by the fact that visually he sees 2 completely different devices, and know one to be an expensive and famous brand, then it's not about hearing anymore, it's about the impression of hearing. and those 2 can be vastly different as the brain likes to pick information from all our senses and previous knowledge to help interpret stuff. so as with
@gregorio's favorite McGurk effect, sight can and will have some impact on what we "hear". so the important distinction here is really the good old objective vs subjective. are we talking about sound and only sound? or are we talking about our impression of the sound and only the sound(which will include notions such as audibility), or are we talking about impression of the sound caused by the complete multi sensory experience? in which case, what I had for lunch, the color of the box, how long it's been since I heard device X, etc, will all be likely to play some role in our final impression of how we felt the devices "sounded".
here too, the trigger for all the evil zombies saying "blind teeeestttttt" while walking toward their victim, isn't that we have a problem when people happen to enjoy a tube amp because the glow is calming to them. it's that they may talk as if everything they feel is cause strictly by sound when under sighted condition, that is simply never the case. it's really just a matter of not claiming something for all the wrong reasons. I get that it can be tricky, I get that sighted impression are all that most people will ever have in this hobby, and I get that most don't even suspect how so very flawed a human brain and senses are when it comes to making assessments about the objective world. but should typical ignorance of an issue mean that the issue doesn't exist? of course not. we're looking for the truth, not a subjective truth someone happens to believe but is really just being wrong without knowing it.
anyway, if you remove sight(the very dominant sense that our brain trusts over any other) while listening to stuff, you already have drastically improved you chance to have sound as the cause of your impressions of sound. which is important if you're going to come on a forum to tell others about how device X
sound is warmer and blablablah, instead of saying that you felt as if it was warmer. the second statement is never false so long as you believe it, it's not claiming that the sound is a certain way, only that you felt a certain way. it's usually the right way to describe a sighted experience.
3. Another basic question! Is there such a thing as "as the artist intended?"
yes there is. at each step of the production, someone had an intent when doing whatever he was doing. now what remains of the guitarist's intent on his CD, hard to say. his power of decision might have gone all the way, or maybe he played in the booth someone told him they had all they needed and he was never asked anything ever again.
the follow up problem is that your speakers or room or headphones are almost certainly not giving you a sound like they had while playing or like the engineer had while mixing or listening to the final master one last time. so I'm tempted to say that anybody using that argument might have good intent, but is most likely full of crap in the context he's talking about.