Burn-in...everything you need right here! (See links)

[Theblackbeard]

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The way I see burn in is this: it doesn't hurt anything or cost anything. If adding an extra 40 hours of time shortens the headphones life span there are bigger problems. I am pretty sure I've heard burn in differences but since I have no way to measure I won't call it fact. When I get a new set of cans I just leave them run overnight a few days. If nothing else, its free peace of mind

Agreed, and in the end to each his own.  Whether brain or non brain about it
 
Cheers

 

[tinyman392]

Quote:

The way I see burn in is this: it doesn't hurt anything or cost anything. If adding an extra 40 hours of time shortens the headphones life span there are bigger problems. I am pretty sure I've heard burn in differences but since I have no way to measure I won't call it fact. When I get a new set of cans I just leave them run overnight a few days. If nothing else, its free peace of mind

 
I wouldn't be so quick to say it hasn't been measured.  It just hasn't been measured in the small scale (much harder to really measure stuff on a small scale this way).  On the large scale, however, break in has been shown.  This is just one example of it: http://www.gr-research.com/myths.htm

 

[Theblackbeard]

@Tinyman392
 
An interesting read, thanks for sharing.
 
TBB

 

[thoughtcriminal]

I wouldn't be so quick to say it hasn't been measured.  It just hasn't been measured in the small scale (much harder to really measure stuff on a small scale this way).  On the large scale, however, break in has been shown.  This is just one example of it: http://www.gr-research.com/myths.htm

Interesting read. I agree with the science of it, burn in does happen. The question is how perceptible is it? The answer is "who cares, its not that difficult to do"

 

[tinyman392]

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Interesting read. I agree with the science of it, burn in does happen. The question is how perceptible is it? The answer is "who cares, its not that difficult to do"

 
That's a hard question to answer.  We don't actually know too much about our own perception to even answer that question  Only time will tell.  

 

[jaddie]

Quote:

 
I wouldn't be so quick to say it hasn't been measured.  It just hasn't been measured in the small scale (much harder to really measure stuff on a small scale this way).  On the large scale, however, break in has been shown.  This is just one example of it: http://www.gr-research.com/myths.htm

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.

 

[tinyman392]

Quote:

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).  
 
Sources: 
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

 

[jaddie]

Quote:

 
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).  
 
Sources: 
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

 
 
Those test are interesting, but as you say, somewhat inconclusive.  Both show slight variation over time of the unit tested, but both are "uncontrolled" tests.  They should have tested un-burned-in sets as well to see if there was something else going on that might affect the data.  Also, the changes are so slight as to be inaudible.  Rin makes files available for ABX testing, then eliminates the possibility of an ABX test by identifying the files.  Neither specifies the type of test equipment used, though Tyll states what he uses elsewhere, perhaps Rin does too.  Tyll draws conclusions within his text that there is evidence of the effect of burn-in, then retracts that statement in his conclusion.  
 
The change in impedance you mention: Tyll's sample shows both increase and decrease in impedance with burn-in at various points in the spectrum.  Rin's shows a general reduction, which would could be explained by a slight increase in flexibility of the diaphragm with burn-in, but certainly heating isn't a factor, and in any case the change is so small that without a control it's possible its drift in the test setup.  

 

[goodvibes]

Leave it for the sound science forum. My ba jh13s changed a lot in the 1st 100 hrs. and I don't wear them during breakin (not brain burn in). I compare with a file I was at during the recording. I guess 'a lot' is relative but significant for me. The idea that you can or even know how to measure everything we can hear is very misguided. Measurements are guidelines, for target function on design and troubleshooting. Not final arbitrators.

 

[boost3d]

After owning JVC FX40's 100% believe in burn-in. Probably one of the best IEM's to advocate burn-in imo.   

 

[jaddie]

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Leave it for the sound science forum. 

 
OK....so is this a "subjectivist only" forum?  I didn't notice that posted anywhere, or I wouldn't have entered. But I wasn't the one who posted links to the "tests". 

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The idea that you can or even know how to measure everything we can hear is very misguided.

Who said anything about knowing how to measure everything we can hear?  Mostly, measurements in the posted tests show a lot of things we can't hear, which is the case with most of these test results. The big problem is correlation of measurements with what is audible, and that's not what this thread is about.  The posted tests are inconclusive, but tend to indicate there is a measurable effect of burn-in, which is what this thread is about.  The tests are not conclusive because they are incomplete, and the effects shown are tiny. 
 
If a change is audible, then its measurable in that a group of people can reliably identify the change.  None of that has been done either, but if it were, the objection that test equipment can't measure what we hear would be circumvented.  The test instrument would be humans with ears.  
 
What's hard to quantify is beliefs, which may or may not be based in fact.   
 
Sorry to have disturbed you with science.

 

[Theblackbeard]

Quote:

Who said anything about knowing how to measure everything we can hear?  Mostly, measurements in the posted tests show a lot of things we can't hear, which is the case with most of these test results. The big problem is correlation of measurements with what is audible, and that's not what this thread is about.  The posted tests are inconclusive, but tend to indicate there is a measurable effect of burn-in, which is what this thread is about.  The tests are not conclusive because they are incomplete, and the effects shown are tiny. 
 
If a change is audible, then its measurable in that a group of people can reliably identify the change.  None of that has been done either, but if it were, the objection that test equipment can't measure what we hear would be circumvented.  The test instrument would be humans with ears.  
 
What's hard to quantify is beliefs, which may or may not be based in fact.   
 
Sorry to have disturbed you with science.

 
Nothing wrong with opinions and personal experience either though.  In my experience, there certainly can be a difference between cans new out of the box and the same cans after over a hundred hours of usage.  It may all be in my mind, but it has been said that reality is second only to perception.  I tend to agree.  
 
Happy to read all your comments.  All are welcome here, unless you want to troll, in that case please go play some console fps's and let it out there. 
 
Cheers,
TBB