@devinplombier Glad you're enjoying the thread. The faith/reason framing is rhetorically satisfying but imprecise — this is really a dispute about burden of proof and what counts as sufficient evidence. Both sides think they're being reasonable.
That said, your component taxonomy is the most useful contribution in this thread. Mechanical break-in for speakers and tubes is physically coherent; thermal stabilization for SS gear is real but trivial; cable and power cord burn-in is where the physical rationale collapses and the faith diagnosis actually bites. Lumping all of these together under "burn-in" is what generates most of the confusion here.
One note on Kalchev: his review is aimed precisely at the cases you're most skeptical about — cables, power cords — where listener psychology does the most unacknowledged work. Speaker break-in is a different phenomenon and probably deserves its own conversation.
Finally, on "no one will be converted": that may be true of ideological debates, but it wasn't the spirit of the original post. I introduced the Kalchev study not as proof of anything but as one piece of scientific literature on the subject, and explicitly invited others to contribute any research they were aware of. The goal was to see what some literature actually says, not to win anyone over. If the thread produced more light than heat, that's enough.
It’s more of a compendium of previous studies than it is a study itself. It’s a narrative of existing literature that represents one side of the discussion only. The author doesn’t pretend to explore whether there are actual physical factors (mechanical changes) in a component that could cause burn-in.
Either tendentious or simply uninformed. Your "narrative review vs. study" distinction doesn't hold up. A narrative review is a recognized study type — it has a defined research question, a method for selecting and synthesizing literature, peer review, and an original epistemic contribution: the synthesis produces conclusions about the state of evidence that no individual primary study contains. By your logic, meta-analyses wouldn't count as studies either, which is an absurd result given that they sit near the top of the evidence hierarchy in medicine.
Kalchev announces exactly what he's doing in the title — a comprehensive exploration across physiological, psychological, and societal domains. He doesn't hide the physical question; he brackets it as outside his remit. Your own phrasing — "he doesn't *pretend* to explore physical factors" — is actually a point in his favor. Honest demarcation of scope is methodological integrity, not a deficiency.
Because the study brackets the physical question, it shouldn't be cited as though it settles it. But that's a claim about what the study establishes, not about whether it qualifies as a study. I'm done replying about this. I now judge it as trolling.
