Burn in and peer reviewed brain research

Another amalgam that merits unpacking is that of price / cost / value on the one hand, and sonic improvements on the other. 

The accepted dogma goes like this:

- It is known that the more expensive a component is, the better it will sound in your system; and that is how it should be, for you get what you pay for.

And the response goes something like this:

- People who spend significant dollar amounts on components whose ability to affect sound quality is controversial and fails basic scientific scrutiny are fools.

But in reality, the two are not linked in any logical way, and both are false. If a person wishes to spend $2000 on an Ethernet switch because it is beautifully carved of solid aluminum ingot and looks gorgeous on the component rack, that’s perfectly fine; it ought to be okay with everyone; and criticism and mockery are inappropriate and unwarranted - that is, until the owner of the switch starts attributing stunning sonic improvements to their switch (which, naturally, will get even more pronounced after 200 hours of burn-in).

And that goes back to the earlier behavioral psychology-based argument. Depending on why we do things, expectations and stakes can change drastically. 

- If I buy an expensive Ethernet switch because it is reputed to improve the sound quality of my system, and I hear no difference because Ethernet switches are physically incapable of affecting sound quality, then that makes me the guy who essentially just threw good money out the window, and I’m not that guy, no way no how, therefore that switch ought to sound amazing because I spent all that money! That’s a tough spot, because now I have to make up value to justify the price tag, as opposed to the other way around.

- But if I buy the same switch because I find it beautiful and I feel that it will complement my meticulously curated system, I’m only interested in its symbolic value - which is entirely mine to determine - and if a naysayer manifests, I only need invoke my prerogative to spend my money as I wish, and that’s an easy argument to win.

Not every object has to do something in order to hold value, and it’s silly and counterproductive to pretend otherwise. Look at jewelry; we’ve been buying jewelry for tens of thousands of years. What’s wrong with audio jewelry?

I can't say that I've noticed differences after burn-in for electronics or cables. I do, however, believe that other people are hearing it.  I would never buy gear that didn't sound good out of the box with hopes that it would get better. 

I have heard differences in tubes after break in.  In one case, the sound did not get better. 

@sls883 

"I have heard differences in tubes after break in.  In one case, the sound did not get better."

Interestingly, a tubes sound does not change over time. Once you apply power, a tube comes up to operating temperature in a few minutes and you're good to go.

What might account for small, if at all noticeable changes in a preamp's or amplifier's sound are minute changes in the characteristics of all the other components in the device primarily from the heat they're generating. In addition, the gaps in the windings of chokes and transformers get smaller as they warm and their transfer function becomes more efficient.

@devinplombier 

Interesting comment – the price/value/sonic-quality conflation is real, as is the sunk-cost psychology. I like the "audio jewelry" framing — if someone is buying for visual aesthetics and symbolic value, they’re explicitly *not* making a *sonic* claim and empirical criticism that they don’t care about sound doesn’t touch them.

As we know, the audiophile market sells visual looks and sonic performance, and most buyers want both. For the buyer, visual, symbolic, and sonic justifications tend to collapse into each other — especially after an expensive purchase, when motivated perception kicks in hardest. The behavioral psychology literature, including Kalchev, would predict exactly that. So if a buyer is using the "audio jewelry" rationale, they’re intellectually honest when it’s a genuine, prior motivation. Often, though, it functions as a retroactive justification — which puts it back inside the trap the study accurately describes.

None of this is really blameworthy on a human level. The issue on an audio forum is that many assertions are offered as if they were straightforward testimony about sound — meant to advise others about sound — so if someone is arguing from mixed motives, it will come across as bad advice, possibly wasting others’ time and resources, and advancing falsehoods about sound. There are worse falsehoods to tell, of course, but on an audio forum, it gets singled out.

Regarding tubes, I understand that a tube reaches operating condition within minutes of applying power is true — thermal stabilization is quick. But I thought that tubes do change over time in ways unrelated to thermal equilibrium. For example, cathode emission stabilizes over the first hours of use as oxide layers settle; getter activity can shift; mechanical components (the internal structure is surprisingly delicate) may take time to fully stabilize under repeated thermal cycling. These are acknowledged in tube manufacturers’  documentation and in electrical engineering literature. The expected degradation curve over a tube’s lifespan is also well established, which presupposes that tubes change with use by definition. How much of this is audible? That’s a harder question! But I’ve heard my tubes sound worse before they failed.

On tubes: 
https://jacmusic.com/html/EE/EE12-Burn-in/V2/EE-12-about-burn-in.html

https://www.effectrode.com/knowledge-base/secrets-of-the-tube-alchemists/

Got my speakers 6 weeks ago. Created a new PEQ setting with a umik-1 mic and

REW. A few days ago, got a vintage turntable and created a new PEQ profile to use when playing vinyl.  Since I had the umik-1 setup, I remeasured the speakers. In same position, song, volume....zero difference on the REW graphs before & after. Wouldn’t care if there was, just sharing my recent experience.

Note: I work from home, speakers are on 12-18hrs per day, ~700hrs of use. To add, these are active speakers, so measurements were on speakers, internal amps, DSP and new xlr cables.