Originally Posted by jaddie
I'll agree with others, it's interesting...but irrelevant in a discussion of headphones. The materials used in a woofer are completely different, the construction is completely different, all the T/S parameters are literally in another world (XMax, if you want an example). Note that the largest differences post burn-in were in Fs, and mostly it changed downward a few Hz, the largest change was about 7Hz. When you look at the mechanical movement, heating, power, and materials, it's very clear that the article shows burn-in effects for woofers. But that's all it shows.
I also see that the attempt at myth-busting was badly done. Myth 1 was only half addressed, Myth 4 is a question of degree.
Too bad there's nothing like this done for headphones. You'd need someone with a simulated ear system to do it.
Tyll has done it with a few over-ear headphones, so has Rin. Each time, they find very small differences in the frequency scale, Tyll even makes a statement where the K701s hit a point of no return where they diverged away from where they came from indefinitely. The changes, he believes however, were too small to be audible. I feel that it's still up to question whether or not the 1-3 dB changes across the spectrum can be audible. Questionable != is. The other change that has been seen, as documented by Rin, is that with IEMs and headphones alike, the impedance went down as the headphones burned in (and the system heated up). This is actually very interesting as the laws of physics state that impedance should go up with a hotter system, not down. Something caused it to go down, we don't know what, or even why.
Rin does have others as well, but the VS02 is his most recent. Whether or not any of this is audible is up to question, but something is happening to the drivers to cause some of these changes. Unlike the headphones though, the VS02 sees very little frequency change, but does see changes in decay. The FR changes in the K701 can also be due to pad softening as well. There are still many questions on what caused these changes.
TLDR: both cases shown above (and below in sources) show that the evidence of burn in is neither confirmed or denied. Remember, they ask the question of whether or not burn in is even audible, not just observable through data (and even that is up to question).
Tyll's 701 burn in: http://www.innerfidelity.com/content/evidence-headphone-break
Rin's VS02 burn in: http://rinchoi.blogspot.com/2013/01/the-effect-of-break-in-vsonic-vc02.html
Edited by tinyman392 - 2/24/13 at 10:24pm