[frtorreira]

Hi,

I would like to know if there is any experimental evidence of burn-in effects on headphones. If so, I would appreciate the references. I don't intend to open a new debate or hear about personal experiences. I am just curious if any controlled perceptual experiment has addressed this issue.

 

[1Time]

I know of no such experimental evidence. Surely at least a college student has done this before though.

Here's the Burn-in FAQ.

I copied the following from Head-Fi's FAQ:

"Why do people choose to burn in a new pair of headphones shortly after getting them?

Fresh out of the box, a pair of headphones may not sound as good as a well used pair, as the designers have intended. Often, people want their headphones to sound the way that they are intended as soon as possible. Most people don’t want to wait for weeks or months of regular use, so the choice is to expedite burn in by getting the process over with in the first week of ownership. Others choose to listen to their headphones as they change over the burn in period.

How much does burn in effect the sound of the headphones?

Some say burn in has a drastic effect, some say there is little effect, and some say that there is no effect. The amount of change resulting from burn in will be different for each model of headphones."

 

[eruditass]

i dont know why no one has ever attempted a frequency response out of the box and much later. of course this would not be the whole story.

 

[frtorreira]

Thanks 1Time. I had already read it. I am not asking about personal observations or even miniexperiments conducted by some college student in their dorm, but rather about carefully controlled experiments, perhaps published in a journal article, some kind of report, etc. I suppose the industry has some stake in this issue. I would be surprised if no testing had been conducted, but haven't found any reference so far.

 

[frtorreira]

Quote:

Originally Posted by DoomzDayz /img/forum/go_quote.gif i dont know why no one has ever attempted a frequency response out of the box and much later. of course this would not be the whole story.

Well, this would be interesting too. I am more interested in perceptual studies though.

 

[b0dhi]

Most of the differences I've heard after burn-in were related to inner detail and seperation, not so much frequency response. There were some small changes ofcourse, maybe about 1-2dB.

BTW it's exceedingly difficult to find specs on high end audio that aren't flattering. For example, I couldn't find any detailed info on IMD for headphones (found a couple for speakers but they were both testing "easy" frequencies where the distortion would be low).

 

[Psiga]

Most of the tests that people conduct are garbage, anyway. ~Whee, look at me, I did a frequency test!~

Break-in with drivers is like break-in with shoes: Takes a while for the fresh-from-factory materials to get into their comfortably flexible place. Are you gonna hear a huge difference? Can you jump higher with an old pair of Nikes than you can with a new pair, or vice versa? Probably not to any appreciable degree. But the tightness of new shoes may translate into discomfort. Similarly, the tightness of new drivers may translate into problems rendering the envelope and phase of a sound.

We are, among other things, talking about the time it takes for the magnet to push the diaphragm into a desired decibel level at a desired frequency.

Check this link, and scroll down until you see some images:
http://www.bbesound.com/technologies/BBE_HDS/
It's a simplified diagram, but gets the point across pretty well. Fighting against the inertia of the magnets, resonance of the diaphragm, tension of the damping, and any other elements inside of a speaker, all contribute to a mis-shapen waveform.

Mis-shapen, but when averaged out on a frequency response plot, it still hits the desired frequency at the desired amplitude.

To my knowledge, there are few or no Standardized Scientific Tests™ which reliably put a headphone through its paces on those teeeeensy tiny details; the things that go beyond generalized frequency and amplitude.

So. This doesn't solve the riddle, you know? But it at least gives a hint that there's more to it than pure imagination. I'm not saying that a lot of 'burn-in' experiences aren't pure imagination -- just saying that frequency response tests by their very nature do not account for the kinds of details which burn-in would be affecting.

 

[frtorreira]

Quote:

Originally Posted by Psiga /img/forum/go_quote.gif To my knowledge, there are few or no Standardized Scientific Tests™ which reliably put a headphone through its paces on those teeeeensy tiny details; the things that go beyond generalized frequency and amplitude. So. This doesn't solve the riddle, you know?

Well, perceptual studies would certainly be of more interest IMHO. When some people argue that there is a night and day difference between burnt-in and out-of-the-box headphones, how can we disentangle autosuggestion or habituation from physical burn-in effects? There are simple scientific ways to address this issue (ABX for instance).