[abm0]

  Hearing an effect and then measuring it badly is more or less a gift to confirmation bias.

Except I didn't hear and then measure, I just kept measuring and doing short listening sessions at long intervals until I finally liked what I heard. At 115 hours in I was still pretty disappointed and thinking the reviews had way overhyped this model and/or the benefits of burning headphones in, or that I just had a pair that was especially unresponsive to burn-in, that I would have to take the loss and re-sell them etc., but I kept going because the highest number of hours anyone had recommended for these was 400 or so. And 80-ish hours of pure sweeps later... boom! There's a sound I can enjoy long-term. There's that burn-in effect everyone was talking about.
 
And the coincidence of a better subjective experience, better measured graph, and a new burn-in method for the last leg (I'd never done pure sweeps until then; very short sweeps had been part of some mixed pink noise + sweeps sound that I used for the first 50 hours, but those added up to too little to be comparable to 80 hours of continuous pure sweeps, plus I got more confident/desperate with the volume as well toward the end) simply does not allow me to seriously doubt the effect was real - that the sound changed due to driver burn-in and that the best method to achieve that turned out to be playing 20-20k frequency sweeps at a volume somewhat louder than would be comfortable for long listening sessions.

 

[abm0]

  you just keep creating your own enemies.
[...]
reality and the requirements to make proper measurements.

I've already agreed with everyone about what needs to happen for the hypothesis to be properly proven (maybe with some quibbles about how stringent the controls should be in order for the results to be considered convincing - I still highly doubt the part about millimeter-positioning; if that were true, all those best-in-class, highly expensive models out there could be turned to crap by moving them on your head slightly or, worse, by having the wrong shape of head or external ear.

). What's creating enemies is continuing to bash my experiment past this point, past this admission.

 

[sonitus mirus]

I'm no enemy, friend.  I appreciate that you took the time to actually make an observation and shared these results with everyone.

 

[castleofargh]

 

  you just keep creating your own enemies.
[...]
reality and the requirements to make proper measurements.

I've already agreed with everyone about what needs to happen for the hypothesis to be properly proven (maybe with some quibbles about how stringent the controls should be in order for the results to be considered convincing - I still highly doubt the part about millimeter-positioning; if that were true, all those best-in-class, highly expensive models out there could be turned to crap by moving them on your head slightly or, worse, by having the wrong shape of head or external ear.

). What's creating enemies is continuing to bash my experiment past this point, past this admission.

but that can happen. not turning them into crap, but altering the signature measurably for sure. even more so when there are reflections on different surfaces at different angles, moving just a little can have a significant impact(comb effect and stuff like that). just look at innerfidelity's measurements, it's a special case as the headphone is put in kind of ideal situation to simulate a real head. but even then, Tyll always does several measurements(the grey lines on the frequency graph) at different positions for that very reason. and the measure shown in color is an average of all the other measurements. all those are done on a dummy head so within the possible movements of the headphone around the fake ears. and some have huge variations, others have a small ones. just like speakers, some have a steady signature only at one point, some sound relatively stable in a wider area(usually the expensive stuff for speakers

).
on my hd650 for example, if I move both sides like 0.5cm toward the back of my head instead of centered(still with a good seal and not pressing on my ears), I get a louder 10khz that is IMO audible.

 

[Yoshi948]

So, I'm not sure if anyone has posted this, but Tyll over at Innerfidelity did an article on breaking-in headphones. It's quite an interesting read.

http://www.innerfidelity.com/content/measurement-and-audibility-headphone-break


tl;dr:





So there you have it. 

I thought it also had a phycological factor. Your brain modifying the "sound signature" to fit to your liking. Although, not too dramatic. Since each headphone will sound different. So yea, burning-in is really a placebo. It's your brain making it feel like it's burn-in. That's why listening to music over and over will "change" a headphones sound.

 

[Dulalala]

Well, just to add my opinion here...
(disclaimer: I didn't read the rest of the thread so apologies if I repeat any information already given) 
 
In my experience, burn in is dependent on the headphone/IEM. I've only really experienced "burn in" that was drastic enough to convince me it wasn't a placebo once. I was helping a friend purchase an IEM a while back. I demoed the model at the shop but once we opened the new one, I noticed that it sounded rather different. About 2 months later, another friend of mine purchased the same IEM model, so I took that opportunity to AB them, the older pair and the newer one. The difference was enough that I was sure it wasn't a placebo effect. Now I have zero evidence for this, nor can I get any. I don't have a microphone good enough to make a frequency response and even if I did, it happened a while ago so I'm sure the "newer" pair has already been used up enough for any "burn in" to occur. 
 
The IEM purchased was the Audio Technica IM50 for anyone interested.

 

[LaughMoreDaily]

So yea, burning-in is really a placebo. It's your brain making it feel like it's burn-in. That's why listening to music over and over will "change" a headphones sound.

Burning in is a placebo? Lol. Yeah right, I knew it was real before I ever even knew what burning in was. If the brain is that smart to make something sound better just by playing it through a pair of headphones in another room when we're not even listening them, that'd be a joke in itself. It's possible but highly doubful. 
 
We have to remember not all companies, brands, etc make their headphones the same way. Some sound amazing out of the box, while others sound terrible but eventually after burn in, sound better, much better, and some just sound a little better. It's really about the quality of materials.
 
Maybe some people's ears just aren't smart enough to notice burn in? It's quite possible.

 

[Yoshi948]

Burning in is a placebo? Lol. Yeah right, I knew it was real before I ever even knew what burning in was. If the brain is that smart to make something sound better just by playing it through a pair of headphones in another room when we're not even listening them, that'd be a joke in itself. It's possible but highly doubful. 

We have to remember not all companies, brands, etc make their headphones the same way. Some sound amazing out of the box, while others sound terrible but eventually after burn in, sound better, much better, and some just sound a little better. It's really about the quality of materials.

Maybe some people's ears just aren't smart enough to notice burn in? It's quite possible.

It is placebo... The more you get used to them, the "better" they sound. It hasn't even been scientifically proven .

 

[Intensecure]

"Yeah right, I knew it was real before I ever even knew what burning in was."
Just a slight case of expectation bias there, possibly.
"Some sound amazing out of the box, while others sound terrible but eventually after burn in, sound better, much better, and some just sound a little better."
OK, you have no proof of any of that, anecdotal evidence is not proof, before you bother offering any, and they always sound better huh? Even the "terrible" sounding ones.. Wow, quite magical properties this "burn-in" possesses. Defies the law of averages, as well as common sense.
"It's really about the quality of materials" - well, yes... and no. You need to provide a bit more evidence of why you think that is the case. And how does it relate? The "terrible sounding" ones are the bad materials and take more "burn-in" or is it the other way around?
"Maybe some people's ears just aren't smart enough to notice burn in? It's quite possible"
Actually it would be the brain that isn't smart enough to notice burn-in, and I would agree with you, but not in the way that you would conclude.
All in a days laughs..Peace, out.

 

[castleofargh]

 

Burning in is a placebo? Lol. Yeah right, I knew it was real before I ever even knew what burning in was. If the brain is that smart to make something sound better just by playing it through a pair of headphones in another room when we're not even listening them, that'd be a joke in itself. It's possible but highly doubful. 

We have to remember not all companies, brands, etc make their headphones the same way. Some sound amazing out of the box, while others sound terrible but eventually after burn in, sound better, much better, and some just sound a little better. It's really about the quality of materials.

Maybe some people's ears just aren't smart enough to notice burn in? It's quite possible.

It is placebo... The more you get used to them, the "better" they sound. It hasn't even been scientifically proven .

placebo doesn't mean a device can't also go through changes over time. they aren't mutually exclusive propositions.
what is wrong is to entirely discard placebo thinking "I know what I heard" or "I remember how it sounded", because that's a little like the mad person in the asylum saying "I'm not mad". nobody believes it aside from maybe the guy himself. we all have memory failure and expectation biases, that's how humans are. self confidence doesn't change that, it only makes people claim false stuff more often. ^_^
 
IMO the search for truth doesn't give us the luxury to just cherry pick the variable that agrees with us. proper measurements tell us if the sound changed over time, not a dude thinking his memory is accurate. most of this debate is really about people thinking they don't need a proper method to test things, or actual evidence to make claims.
one doesn't demonstrate burn in with an opinion!

 

[abm0]

You don't get to pick and choose which InnerFidelity article to read and just declare that the "final verdict", much less "scientifically proven" (haha).
Here:
http://www.innerfidelity.com/content/evidence-headphone-break#quXyjIDdy5UOxmLS.97
http://www.innerfidelity.com/content/testing-audibility-break-effects
 
... and even in the article posted earlier on this thread there was an objective improvement in terms of intermodulation distortion, so I can safely say that every single time Tyll Hertsens posted an article about burn-in it contained evidence in support of burn-in being a real effect.
 
And of course he's not the only one:
http://www.gr-research.com/burnin.htm
http://rinchoi.blogspot.com/2013/01/the-effect-of-break-in-vsonic-vc02.html?m=1
http://rinchoi.blogspot.com/2014/02/the-effect-of-break-in-creative-aurvana.html
 
And a sort of round-up of the different claimed/possible types of burn-in:
http://diyaudioheaven.wordpress.com/tutorials/burn-in/
 
So knowing all this I maintain that there are two things to keep in mind if the issue is going to be "settled" or a verdict to be established in any kind of "final" way as regards night and day / clearly audible changes in headphone drivers (not pads, not listener brains):
1. not all drivers are the same, just because one driver doesn't change much with burn-in it doesn't mean no other driver will (the cheapest ones should have been the focus of these experiments, not expensive AKGs and Sennheisers and whatnot)
2. if a rigorous InnerFidelity-style experiment is performed on a brand new Superlux HD668B there will be orders of magnitude more burn-in effect than what Tyll saw in his previous attempts.

 

[hoanguyen]

I'm new here and have not read most of the posts above.
 
Few weeks ago I got the Grado PS1000e. listened a couple hours and then burned it over 200 continuously hours.  I could not tell the difference between before and after burning.  It is the same as I could not tell the difference between $5 and $1000 interconnection cables (or speaker wire as long as large gauge sizes.  had friends who spent several thousand dollars for cables and claimed that the sound was significantly improved but I did not heard the difference).
 
Obviously, I do not have golden ears as many people.
 
HN

 

[Mr Rick]

  I'm new here and have not read most of the posts above.
 
Few weeks ago I got the Grado PS1000e. listened a couple hours and then burned it over 200 continuously hours.  I could not tell the difference between before and after burning.  It is the same as I could not tell the difference between $5 and $1000 interconnection cables (or speaker wire as long as large gauge sizes.  had friends who spent several thousand dollars for cables and claimed that the sound was significantly improved but I did not heard the difference).
 
Obviously, I do not have golden ears as many people.
 
HN

Lucky for you. ( And me ) It saves us $$$ in the long run.

 

[Petyot]

 
And a sort of round-up of the different claimed/possible types of burn-in:
http://diyaudioheaven.wordpress.com/tutorials/burn-in/
 

 
From this article :
 
Conclusion:

For electronics burn-in (as in changing the sound signature over the first time period) is fiction as in changing sonic signatures.

Some electronic circuits may need some time to warm-up and achieve their optimal operation points. In some cases this MAY be audible. Burn-in this is not.

Cables and 99% of all passive components do not need burn-in nor will they actually change electrical properties over time, certainly not to levels that reach the audibility threshold. Some may feel their audible thresholds are MUCH lower than those of the ‘non-hearing’ crowd.

Scientifically controled tests, however, have never shown that the thresholds differ that much between trained listeners and audiophiles.

Some components do change with age but doubt that this will increase the perceived sound quality over time.

It may take years or even tens of years before degradation may become noticeable.

Parts that do degrade over time (wear an tear, oxidise or get dirty) will usually degrade the sound but also after a LONG period of time.

For electro-mechanical-acoustical components like headphone drivers it is clear that break-in exists BUT …. the audibility of this remains to be seen.

From a technical viewpoint warm-up and break-in is real but think brain-in is just as real.

IMO the many ‘reports’ of ‘considerable’ changes in sonic signature are greatly exaggerated or could be attributed to other reasons than an actual change in performance/sound.
Of course, what some may call substantial may be marginal, not worth mentioning or inaudible to others.

So before one says .. burn-in/break-in is real and I can clearly hear the improvements one may have to wonder if these perceived improvements are ‘real’ and caused by actual changes in the driver or that they may be caused by one or more other reasons.

That's a good synthesis of what I think on that matter... 

 

 

[jagwap]

   
From this article :
 
Conclusion:

For electronics burn-in (as in changing the sound signature over the first time period) is fiction as in changing sonic signatures.

Some electronic circuits may need some time to warm-up and achieve their optimal operation points. In some cases this MAY be audible. Burn-in this is not.

Cables and 99% of all passive components do not need burn-in nor will they actually change electrical properties over time, certainly not to levels that reach the audibility threshold. Some may feel their audible thresholds are MUCH lower than those of the ‘non-hearing’ crowd.

Scientifically controled tests, however, have never shown that the thresholds differ that much between trained listeners and audiophiles.

Some components do change with age but doubt that this will increase the perceived sound quality over time.

It may take years or even tens of years before degradation may become noticeable.

Parts that do degrade over time (wear an tear, oxidise or get dirty) will usually degrade the sound but also after a LONG period of time.

For electro-mechanical-acoustical components like headphone drivers it is clear that break-in exists BUT …. the audibility of this remains to be seen.

From a technical viewpoint warm-up and break-in is real but think brain-in is just as real.

IMO the many ‘reports’ of ‘considerable’ changes in sonic signature are greatly exaggerated or could be attributed to other reasons than an actual change in performance/sound.
Of course, what some may call substantial may be marginal, not worth mentioning or inaudible to others.

So before one says .. burn-in/break-in is real and I can clearly hear the improvements one may have to wonder if these perceived improvements are ‘real’ and caused by actual changes in the driver or that they may be caused by one or more other reasons.

That's a good synthesis of what I think on that matter... 

 

 
He makes good points.
 
However I've seen graphs of the changing of ESR (Electrical Series Resistance) in electrolytic capacitors over the first few hundred of hours as the electrolyte settles to it's working voltage.
 
I've measured the change in performance as class B amplifiers warm up over hours, depending on their thermal mass.  Not burn in as such, but:  Some use phase change thermal pads, which once flowed, will alter thermal gradients, and capacitance to chassis.
 
Why does everyone think that only frequency response shows sonic differences?  Give someone an oscilloscope and they fix waveforms.  Give them an Audio Precision and they will fix frequency response and THD.  Give them a Klipple.... etc.   Mechanical materials will have difference transient responses if the break in.
 
There is more going on than "it cannot be happening as frequency response is not different enough."