break-in--bane or boon ??

Douglas_schroeder, "To date I have had no one, professional or amateur, contest my findings. I also have found no one who has replicated the test. I suggest those who doubt my little test, who ardently belive in Burn In, get double components and do the informal testing. I can tell you what will happen; you'll not be able to hear the difference. :)"

Well, apart from Geoffkait, I will also contest your findings.

However, before going into that, I will say that the phenomena of the listener "breaking in" to the component is just as real. I myself often notice this during parts analysis, which normally devolves into a mind numbing game of waiting. Our ears surely adapt to whatever's in front of us. I absolutely believe that explains a lot of why people live comfortably with their systems, only to have another listener come away mortified after spending time with it. As both you and Al stated, perhaps the most efficacious means toward countering this remains A/B testing.

The concept of break in parallels things like wearing in a new pair of leather shoes or blue jeans. There's a period where things undergo change; the before and after states behave differently in some sort of way(s).

A few quick anecdotes:
1) Working as a chemist / material science engineer during my 20s at a company that made high technology electronic materials, I performed many experiments on the conductor, resistor, and dielectric materials we produced for the likes of NHK, Vishay, Dale, Sfernice, Roederstein, Mallory, Panasonic, Sanyo, General Motors, etc. Proving the concept of break in to a degree orders of magnitude above irrefutable, the electrical characteristics of these materials do change in large measure during the early part of their lifetime, reaching a plateau of stable operation over what's normally/hopefully a long time prior to entering their phase of age or environmental related degradation

2) A definitive objectivist, Bud Fried, who normally spent about a third of the year in Europe, and influenced a fair amount of the work at companies like Audax, Dynaudio, Focal, Kef, and ScanSpeak from the 1960s through 1990s often recounted the research and development that went on. Practical use of a new driver would produce measurable and sometimes significant change in characteristics such as Cms, Qms/Qts, and xMax

3) A friend of mine whose business is rebuilding loudspeaker drivers often tells me about how the suspension (both surround and spider) changes. He's more of the type who would never measure this sort of thing empirically, but the spider in particular offers a visual and tactile contrast one can discern

4) Some time ago, I found a coupling capacitor shootout on the web. While there are more than enough of these out there, what made this one interesting was something due to the same sort of break in argument among the folks contributing there. Perhaps to satisfy his own curiosity, the gentleman conducting the test decided to run a PC based plotting measurement on one of the caps before (new) and after some run in to see if anything along the lines of "break in" could be detected. He wound up more than surprised at the obvious degree of difference

5) To your specific challenge, I have built several DynaKit ST70 amplifiers. After completing the new unit and confirming the typical measurements, I'll replace one I've been using for a while in that system with the new amp. Though the parts are normally (though sometimes, they're not) exactly the same, the sonic differences are always both obvious and predictable. It takes a good three to four weeks of playing most days for at least a few hours for the new amplifier to catch up to an older one. The same is true, though to a lesser extent both in terms of time and sonics when I go about evaluating parts like resistors and coupling capacitors in an already established unit.

The subject of break in tracks much like cabling. Even today I meet so many audiophiles who maintain that "wire's just wire." I begrudge them not. Likewise, should you continue to go forth feeling that same way about break-in, I understand.

No doubt real for transducers.

Less certain about the rest but not impossible.

I have the same observations with my Stax headphones.

Cable break in is non existant. Other parts do break in but cable do not.

Sorry Donjr, but I'll be happy to demonstrate cable break-in with my Audiodharma Cable Cooker any time you'd like. The difference isn't subtle.

I'm not a cable skeptic, but I trend, with Doug and Al, to being a break in skeptic (with the already noted exception of transducers).

The reason is that the experience of components improving with time is predicted by several well known psychological effects, which collectively suggest that much of the "break in effect" is mostly what people here have been calling "psychological accomodation."

1. The "mere exposure effect": people tend to prefer familiar stimuli. Thus, the more you hang around your component, the more you can, all else equal, be expected to like it.

2. The "mere ownership effect." People tend to prefer things that belong to them, even over *identical* items that do not belong to them. Thus, you can be expected to like what you own.

3. "Self-enhancement." People tend to find ways to view themselves in the most favorable light. You're not the kind of bozo who would drop a ton of coin on a marginal improvement (or step backward) for your system, are you?

4. Self interest. No fancy name needed here. Dealers and manufacturers have a strong interest in promoting the "break in effect"; it makes a good answer for the disappointed customer who might otherwise want a return, and buys time for the psychological processes noted in 1-3 to do their work. Try calling a dealer and saying the item you just bought underwhelms you, and then ask about break in. Do you think the dealer is likely to say "break in is a myth"?

This is not to say that break in is never a factor, and still less to say that people cannot properly appreciate big, and even small, differences in gear. (Bring those big Rockports or Wilsons over, and I'll likely prefer them to my more modest speakers, ownership be damned.)

It is to say that the psychological evidence suggests people would experience the "break in effect" *even if there were no objective improvements in gear over time*. So I would like to see very compelling evidence before attributing the experienced improvement to the gear rather than the listener. (Note that the experience itself cannot be such evidence; it's not the experience that is at issue, but its source.)

John