Simple method to tell if "burn-in" is real: Purchase two identical amps (or headphones or speakers or whatever.) Give both unopened boxes to a friend. Instruct the friend to take them home and place one unopened box in a closet, and to open the other one and use it or "burn it in" by whatever method you choose, but that your friend must do this without telling you which one they "burn in." After the prescribed time, your friend should unbox both units and place them side by side. Have a second friend go get them both without knowing which is which and bring them to your house. Your friend must now set them both up in as identical a method as possible while you are out of the room. (this is where A/B switches can come in handy.) Now listen to identical tracks on them both., If the "burn in" process made any difference you should be able to immediately determine by ear which is which. If not, then, well...
Not bad. Tyll did almost this with a couple pairs of AKG702's (I think). Ran one for weeks or months, set the other aside, ran his test suite on both, and listened. He believed he uncovered very slight differences that point to burn in being a true phenomenon. Or not. It was not blind or double blind though still a pretty objective test.
Yeah, you could do this, but it's not a statistically valid data set with an N of 1 to perform a 1-proportion test.
Or, one could rely on the experience on the community of real-life users here who are sharing their experiences honestly for the benefit of the community-at-large. So, when I posted that my rev 1 Bifrost took about 400 hours to fully burn-in and stop improving in it's sound quality, you can rest assured that those comments were shared honestly and in good faith and without any agenda. Other folks can take that for whatever they think it is worth, and use that intelligence to make a more informed decision about whether a product represents a value proposition for them or not. If it does, great. If not, they can move on to something else. Horses for courses.
That's one of the real benefits of a community like this; folks can share their experiences and sensibilities! It's all good!
I generally stop reading posts once they hit comments along the lines of 100, 400, months of burn in. Falls into the "whatever" category to me. If you believe it, good for you. Edit - this sounds a bit harsh. I don't mean to sound like a dick (though I often do). I just don't buy the hundreds of hours stories. I've tried a couple of noted "hundreds of hours of burn in required" products in the past, and didn't really notice changes past the 5 to 20 hours of mental conditioning in any case. And yes, subjective and vague. It's been several years, and the further past age 50 I get, the shorter my memory gets….
You are correct about my simple test lacking statistical validity, but so too does a single user proclaiming how much "burn in" helped his Whammo Widget Mark 3. As both an engineer and a person who has done statistically valid group testing, the idea that electronics (especially solid state electronics) "improve with age and use" is a myth, one perpetuated by reported subjective perceptions by people who desperately want to believe it. Your perceptions may indeed change with time, but that does not mean the gear has.
As one might expect from my just previous comment, I'm with Ableza on this one. I *think* I've experienced burn in on a couple of pairs of headphones, most recently the Alpha Primes. It could well be mental burn in, though I believe "burn in" or more likely mechanical run in is a reasonable phenomenon to expect from a headphone, as it is in great part a mechanical system with moving parts, flex, wear and tolerances, etc. Or not…. It could easily all be mental burn in, and I have no data to support either on those couple of experiences.
No point in upgrading equipment then, is there?
I disagree with the amp is an amp is an amp, ac is a dac is a dac logic. In a perfectly designed state, yes. Once physical reality sets in, different parts, designs, etc. will (should?) make a difference. I think the differences have been measured, different levels of distortion, different harmonics prominence of distortion, other "stuff".
You bet, so the next time you feel like upgrading send your money to me and don't bother.
You are rotten! Now, if this approach works, please let me know….
EDIT - I just read the intervening post. It looks like this is a non-starter among generally reasonable folk.
My qualifications - Mechanical engineer, decent ear, logical guy, analytical guy, blowhard who likes new, shiny things even if they don't sound any better. Sometimes I like them well enough that I convince myself they sound better. Sometimes they actually do sound better….
