Burn in and peer reviewed brain research

I think electronic warm up or burn in is real but it’s only until the gear warms up.  I used to do the pink noise for 100 hours with new equipment but not anymore.  

@cleeds  Good points. You're right on both counts. Kalchev is a narrative review scoped to human factors, not a survey of physical evidence for or against mechanical change — and I shouldn't have presented it as more dispositive than it is. And the burden-of-proof framing was mine, not his; he gestures at it once but doesn't develop it. The more accurate summary is that the human-factors literature is robust, the physical-change literature remains unresolved, and the two may not be mutually exclusive. Kalchev himself implies as much by leaving the physical question open. Thanks for reading more carefully than I did!

@soix  Nobody is saying your experience didn't happen. The question is what caused it. More important, I think, is that the Kalchev review focuses primarily on headphones and in-ear monitors, not speakers. Speakers are the strongest case for genuine mechanical burn-in: surround compliance, spider stiffness, and cone behavior are all physically plausible candidates for change with use. On designer testimony: they have obvious commercial incentives to encourage extended ownership before judgment is rendered. That doesn't make them wrong, but it disqualifies them as neutral witnesses.

@78sman  Your point about memory-based comparisons is well-taken and underappreciated here — we don't store sound the way a recorder does, we reconstruct it, and that's the central problem with most burn-in testimony. I also like the way you shifted the debate from "does burn-in exist" to "how large is the effect" — that's a more useful question, and the answer probably varies by equipment type. Speakers have the most plausible physical case; other gear may be more liable to subjective projection.

That said, you apply your own caution selectively. You flag the problem with memory-based comparisons, then offer "I've often noticed it sounds better after a few months" as personal evidence — which runs into the same problem, plus the added noise of increased familiarity, changing reference recordings, and shifting listening habits over time. The same skepticism you bring to the formal comparison case probably belongs with the personal evidence too.

The MAIN question I was asking in the post was this: "Has anyone found other literature of this type – physiological, psychoacoustic, rather than engineering/mechanical? I'd be curious to learn about it."

I'm still most interested in that question rather than going round and round. 

@hilde45, you're right.  I should have said that equipment often seems to sound better after a few months of burn-in.  It's evidence, but it's also weak evidence due to the comparisons between two times.

defective units mis-attributed to "needs time" and unit-to-unit variation masquerading as change over time are both real confounding instances that rarely get acknowledged in these discussions.

No one wants to be caught with their pants down.

@hilde45 

"ear fatigue, confirmation bias, placebo effects, and neural acclimatization — that adequately explain perceived changes without requiring the equipment to have changed at all."

Burn-in schmern-in!