I am wondering from an Objectivist perspective what produces the "extraordinary detail" in really expensive headphones? How much of it is a simple manipulation of the frequency response, versus driver construction or other design engineering choices?
I think it's no surprise that many of the "most detailed" headphones, are also noted for extreme mid treble peaks. I'm just curious as to what goes in to make extremely detailed headphones.
if taken seriously, this is a very complicated question. but bigshot is right that the impression of detail and getting the most details are 2 completely different paths. ideally a rather flat frequency response(to your own ear!!!!) is indeed a massive improvement as it's when our hearing would mask the least frequencies. but typically such a response is called boring or dull by audiophiles, while as you mentioned, some well placed treble boost can really increase our impressions of clarity(also give a more pinpoint position for the instruments in space, even if that position is nonsense, we do place things better with shorter frequencies we can still hear). I guess that can play a big role for some listeners who like to focus on this type of feeling.
for the rest it's hard to tell. at least for me it is ^_^. because we could consider a bunch of variables that on some headphones could reach audible levels(at least sometimes), but how would those be interpreted by the brain in term of details? it's really hard to say, because AFAIK it's not even sure that everybody would respond the same way to the same change. it's fairly easy to assume some general idea where better fidelity simply leads to better resolution which in turn leads to more perceived details. and while at audible levels this might hold as an objective principle, it's a lot more difficult to declare that actual fidelity is consistently going to be perceived as an increase in details. I remember someone arguing that a given playback system was more detailed because the bass had "texture". which to me sounded somehow grainy and I personally associated that with noise and distortions so of course I never considered that extra audio information as more details. but the guy certainly did, and he loved it. on headphones, some type of distortion could give that gritty sound that will make it, if not very euphonic, at least very clearly perceived at some frequencies. I suspect that some people are taking that as detail, while others take it as degradation of the signal. hard to give a final verdict on subjective interpretations.
I personally wonder if the typical love for open back headphones is due to how perceiving outside noises almost unaltered has the ability to anchor our brain into reality and make it more accepting of the headphone sounds as also being part of that reality? or of maybe this is completely irrelevant for the brain and what we feel differently are the increased distortions due to limited airflow of closed back headphones, and internal reverb or whatever? or maybe if it's something even less related, like how hot our ears get, having an impact on our experience? it's fairly easy for me to correlate open back designs with a fairly consistent preference of mine(and many others), but when it comes to suspecting a plausible cause for that preference I honestly don't have a clue. but I feel that closed headphones offer me a less detailed experience, despite how objectively I should jump on any opportunity to reduce the outside noises. on IEMs I strangely have the opposite take. I still somehow feel like open designs are overall better, but in term of detail retrieval, the high isolation of my ER4 seems to win over anything vented. and many abx tests support that idea. so maybe I'm wrong about headphones and closed designs would also get me better retrieval of just noticeable differences which by extension could count as better perception of small details? IDK I'm guessing headphones just don't isolate that much in general, so maybe that's why the difference in term of outside noise isn't as self evident for me when seeking small details. but then again, it could be that closed back designs typically have a different FR that more than counter the outside noise reduction? our subjective experience being that pudding of variables, it rapidly becomes a mess to try and guess which one is responsible for what. often there simply isn't one variable doing one thing for the brain. we're based on patterns, if those patterns are complex, then we remember the all complexity as something and another complex acoustic event as something else. changing one or 2 variables might sometimes make us feel more like the first memorized pattern we could associate with great details in our head, or it could just as well completely disrupt the pudding and make it impossible for the brain to accept the experience as any of the pudding versions it learned about.
not sure if my highly technical pudding explanation means something to you, but that's about the best I have.
so personally, in term of real detail retrieval(as sometimes opposed to impression of details), I'd stick to the part I do understand, that got confirmed with experiment many times. frequency response, and remaining below a given amount of distortions. a relatively stable FR, one that extends well all over our own hearing range, one that feels as neutral to our ears as possible. and trying to avoid having above 1%THD at our listening level(might not matter much if it's above 1% in the subs and if the amount of newly generated frequencies are loud only in the low end, but it could be worth looking that up just in case).
along with that idea of stable FR, maybe having left and right driver well matched could have some impacts in some listening tests, but I have no idea how much of impact that would have on typical subjective impression of details. probably none or close to none. but in term of objective fidelity, it's not irrelevant.
