Can the burn-in skeptics leave us alone?
Nov 14, 2011 at 12:42 PM Post #76 of 184
Some did measure the differences in sound frequency. These are highly correlated with physicial changes, if not causal. It is you, who need to provide reasons as to why those experiments are not good enough AND how to make them better (practically speaking). Even so, at worst, the results are inconclusive. At best, you have got your proof.
 
Nov 14, 2011 at 12:53 PM Post #77 of 184
I don't know the studies you are referencing. Do you have links? To date, I've not seen any study that showed changes beyond sample variation (or even corrected for it) in the same model/manufacturer. (e.g. they proved you could tell two headphones from one another - but not that one headphone changed due to "burn in")
 
And just so we are clear. I am not making a positive claim that burn in does not exist. I'm willing to accept that it may well - especially when combined with psychological and placebo expectations - I'm still after a why - and evidence that there are physical, measurable changes in the headphones themselves. I'm fine with inconclusive - especially if that means you all will stop claiming it as true as well. 
 
Nov 14, 2011 at 1:07 PM Post #78 of 184


Quote:
 I'm fine with inconclusive - especially if that means you all will stop claiming it as true as well. 


Those of us who think burn-in happens, are just very receptive or open to it. I wouldn't claim it as a known fact until there is conclusive evidence.
 
The reference I made was to an experiment one did no more than a couple of years ago here on Head-fi, I think it was documented in this sub-forum. You can look for it. It's 4:00am here in Oz...
 
I remember he used the same headphone and meassured the sound levels at different frequencies before and after burn-in. I can't recall the exact detail. I'd expect there is a thread with all the studies and experiments in existence here somewhere. Not in here?
 
Nov 14, 2011 at 8:02 PM Post #79 of 184
Quote:
I don't know the studies you are referencing. Do you have links? To date, I've not seen any study that showed changes beyond sample variation (or even corrected for it) in the same model/manufacturer. (e.g. they proved you could tell two headphones from one another - but not that one headphone changed due to "burn in")
 
And just so we are clear. I am not making a positive claim that burn in does not exist. I'm willing to accept that it may well - especially when combined with psychological and placebo expectations - I'm still after a why - and evidence that there are physical, measurable changes in the headphones themselves. I'm fine with inconclusive - especially if that means you all will stop claiming it as true as well. 


http://www.innerfidelity.com/content/evidence-headphone-break
 
Differences are for the most part below 1 dB. There are some places where differences are larger, but not always predicable (as in, they don't always get smaller or larger consistently with time) so part of it could be variations in measurement conditions. I believe the headphones were left on the dummy head for the entire length of the test, so most of the differences could be explained by pad burn in, more so than driver burn in. If so, the effect would be lessened for those giving the pads a break every few hours of head time, or for those who are burning the headphones in off the head without anything to shape the pads.
 
Burn in does exist, be it driver or pad burn in. The question is how audible is it? The differences shown here, even if they were all accounted for by driver burn in, are much smaller than the claims of burn in enthusiasts who sometimes believe burn in "makes or breaks" a headphone.
 
You know what would be an interesting test? Take three (or four) headphones of the same model, measure them separately (since there's product variation), burn one in on the dummy head with noise for 100 hours straight, burn one in off the dummy head for 100 hours straight, and burn one in on and off the dummy head for 100 hours, two hours at a time with an hour break in between each session. Compare them to their original measurements and do averaging to determine which changed the most.
 
And you can put a fourth one on the dummy head for 100 hours straight without any burn in, to test pad changes.
 
Nov 14, 2011 at 10:08 PM Post #80 of 184
Thanks Head Injury, for the link. I'll read through Tyl's experiment. 
 
Nov 14, 2011 at 10:25 PM Post #81 of 184
http://www.head-fi.org//t/471605/burn-in-experiment-proof/15#post_6390168
http://www.head-fi.org/t/154481/burn-in-time-myth-or-fact#post_1822816
http://www.head-fi.org/t/468146/burn-in-myth/15#post_6338400
 
There's several objective tests for you. I still couldn't find the one I read here some time ago. I think it was on IEMs (Moster Turbine?), measuring the changes in FR. Can anyone remember?
 
Nov 15, 2011 at 12:39 AM Post #82 of 184
The burner-inners can make their point more strongly using the meme generator
http://memegenerator.net/leave-britney-alone
 
Nov 15, 2011 at 2:16 AM Post #83 of 184


Quote:
Soundstage and airiness are really the most prevalent qualities that people report changing.  No machine in existence can test this, bass quality and textures all throughout the sonic spectrum are often reported.  The changes are all very small but as another user here said on the last page, they add up and will create an audibly different experience from stock.  So I laugh uncontrollably when someone claims burn in does not exist after they test frequency response and see no change.  Its like....derpppp
 

 
Sorry, but that's just not true.  The sonic differences between headphones and/or speakers which contribute to the qualities described as 'soundstage' and 'airiness' are a reflection of the sound waves. As such, they have physical properties and they are measurable.  They are likely a product of sound waves interacting with each other in a process described as linear super position.  Starting out with the assumption that something cannot be measured or tested is anti-scientific and implicitly relies upon supernatural explanations.  If the process of burn in does exist, then I can measure it. I don't need any sophisticated machines to do it, although sophisticated machines could help.
 
What I would need would be a number (I'd guess about 150) of brand new model and brand matched headphones which would be randomly assigned to three different groups of equal size: untreated, and treated (burned in using some previously agreed upon method for a pre-set amount of time, say 300 hours), and a third group termed modified which would not be burned in but would be intentionally modified to be somewhat different from the untreated by introducing something like a low-pass filter to slightly modify the sound coming out of them in a way which is measurable using sensitive electronic monitoring equipment, but yet still very subtle.  I would then need a much larger number of individuals (say 300-1500) to perform the experiment on.  Ideally these too would be randomly selected from the Head-Fi population.  Each of those individuals would state whether or not self identify as whether or not they can hear the effects of burn-in, and whether or not they believe they have golden ears.
 
The test would then be relatively simple. Each individual would bring with them a selection of 5 or 10 songs (to be determined prior to the start of the experiment, and every listener would listen to the same number of songs)prepared in whatever format they like.  They could use their own amplifiers, power cables, whatever.  The only issue would be that they would not be allowed to know which headphones they were wearing, and neither would the experimenter (double blinded).  The listener would listen to every song using two sets of the headphones, randomly chosen from an of the possible combinations including: untreated and untreated, untreated and treated, untreated and modified, treated and modified, treated and treated, or treated and modified.  The listener would not know which pairing they were listening to, but would be asked a simple question.  Do these pairs of headphones sound the same to you or not?  There would be no statement of preference recorded.
 
Then we would be able to address a couple of questions.  The first of which would be, on average, can users hear the effects of 'burn in'?  Can some subset of the population reliably hear the effects of 'burn in', while others cannot?  
 
The null hypothesis of course, is that no one can hear any difference and any perceived differences are either due to placebo effect or because the listener had changed.   
 
Personally, I'm agnostic on the issue of whether burn in occurs or not.  I can imagine how use over time would change the voice coils and/or diaphragms involved, and that over time the positioning of the earphones on the users head would change in response to the changing earpads as a result of use.  Grado headphones sound can change in quite marked ways by simply changing the earpads.  On the other hand, I do think it is quite ridiculous to state that a phenomenon exists, but it is untestable.  
 
Nov 15, 2011 at 4:24 AM Post #84 of 184
 
From where I'm sitting (comfortably inside my listening room), there are three things I have become aware of over the years (my personal experience). Burn-in, Play-in and Degradation. Not so obvious to some, is the relationship between the three. Others may differ and that's ok. Enlightment me, humor me but whatever your view, make it respectfully.
 
We all share a sense of community with our love for audio. I welcome your views...
popcorn.gif

 
Nov 15, 2011 at 4:37 AM Post #85 of 184


Quote:
 
Sorry, but that's just not true.  The sonic differences between headphones and/or speakers which contribute to the qualities described as 'soundstage' and 'airiness' are a reflection of the sound waves. As such, they have physical properties and they are measurable.  They are likely a product of sound waves interacting with each other in a process described as linear super position.  Starting out with the assumption that something cannot be measured or tested is anti-scientific and implicitly relies upon supernatural explanations.  If the process of burn in does exist, then I can measure it. I don't need any sophisticated machines to do it, although sophisticated machines could help.
 

 
 
Edit -  Actually, I don't have the strength right now to reply to this lol
 
Nov 16, 2011 at 12:34 PM Post #86 of 184


Quote:
Those of us who think burn-in happens, are just very receptive or open to it. I wouldn't claim it as a known fact until there is conclusive evidence.
 
The reference I made was to an experiment one did no more than a couple of years ago here on Head-fi, I think it was documented in this sub-forum. You can look for it. It's 4:00am here in Oz...
 
I remember he used the same headphone and meassured the sound levels at different frequencies before and after burn-in. I can't recall the exact detail. I'd expect there is a thread with all the studies and experiments in existence here somewhere. Not in here?


Not there here -
 
http://www.head-fi.org/t/505113/my-theory-as-to-why-headphones-appear-to-burn-in/165
 
So there is evidence to show that there is probably some form of audible burn in with speakers.
 
Nov 16, 2011 at 6:22 PM Post #87 of 184
welcome back Clutz.
 
Nov 16, 2011 at 7:42 PM Post #88 of 184


Quote:
Not there here -
 
http://www.head-fi.org/t/505113/my-theory-as-to-why-headphones-appear-to-burn-in/165
 
So there is evidence to show that there is probably some form of audible burn in with speakers.


 
I finally found the thread. The hints were from the second post in your link. I was right. It's Monster Turbine... Copper (done by dweaver). I can't believe nobody has mentioned it here.
 
http://www.head-fi.org/t/495812/a-tale-of-2-iems-montser-turbine-copper-1-vs-monster-turbine-copper-2-how-different-burnin-techniques-gave-me-two-unique-iems
 
I also updated my OP with all the tests and experiments I have found so far (without much trying). I'm certain there's more...so feel free to contribute.
 
To those who say "I don't know any studies/tests/experiments for burn-in". I say to you, you haven't tried. There are countless, just hidden for you to find (if you're really interested).
 
Nov 16, 2011 at 8:28 PM Post #89 of 184
I don't know of any studies* 
 
*that do not make reasonable corrections for sample variation, visual bias, testing variation, etc.
 
If you consider that link well researched evidence, it is not. It is interesting additional data - but it is not evidence, much less conclusive of anything. He himself states: when I did my measurements I got significant fluctuations. What I did was continue to work to get the mic and IEm in the right spot so they had a constant reading and only used the highest reading that I could get for both IEM's. 
 
Right there - I cannot accept any of the measurements provided because there is no consistency - there is no way to know what the actual values should be. 
 
Even when he adjusted his methodology later - it was still a hot mess. It is interesting, but not conclusive (for a lot of reasons).
 
 
As I have stated - I believe there is a burn-in effect. I do not, however, think that the bulk of the change is in the drivers themselves (but rather in the listeners). There is a lot more data to back up psychological adjustment in the listener (and other mental factors) than there is for physical burn in of the phones (much less cables).  
 
Nov 16, 2011 at 9:39 PM Post #90 of 184
If you understand a bit about science (I assume you do because of the words you throw around), you should know that many peer-reviewed articles in science journals have inconclusive results. And data don't just speak for themselves; they always need human interpretations.
 
Just lately, the biggest thing in physics is whether speed of light got surpassed. There's no concensus in the community, and more research and replications are warranted.
 
You'd be surprised how many studies get past the panels without the "right" methodology. That's another story.
 
Most importantly, I never said there is unequivocal evidence. I agree that this area of research still needs much further study. There hasn't be a controlled experiment with a large enough sample to convince most people, that I know of. (Don't expect everyone will be convinced even if there is such a study, because even though human-induced climate change is a scientific fact (as in agreed upon by most scientists) there are still both scientist and non-scientist skeptics out there, however few that is)
 
Contrary to what people here think based on what they have said in this thread, I personally think psychological acclimation has a stronger effect than physical/mechanical changes in the headphone. There is to be expected some reverse/two-way causality there as well, it wouldn't be an easy task to separate the two.
 

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