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My theory as to why headphones appear to 'burn in'. - Page 12

post #166 of 261
Thread Starter 

This is from a forum where part of a book available on Amazon has been quoted. It again shows that once speakers have been used they can take a significant length of time to return to their original state and one of them did not quite make it.

 

http://www.thecarversite.com/yetanotherforum/default.aspx?g=posts&t=2232

 

So my new theory of headphone burn in (with added proof) is that headphone's either do indeed burn in (but it is not necessarily permanent) or they do not burn in.

 

If left long enough between listens, the effects of burn in may have totally disappeared. How long is long? From a few seconds to days. Some headphones may not return to their original state, so can be said to have truly burned in. Some cannot be burned in as they keep quickly returning to their original state. Some are half way houses where, if used regularly may never get a chance to return to their original state. But if used occasionally they do have time to return to their original state.

 

Which headphone is which, I have no idea.

post #167 of 261

I still think most of it is due to becoming used to a particular headphone's/speaker's sound.  Just my unscientific but personal experience $0.02.

post #168 of 261
Thread Starter 

Yes, a unified theory - there is some evidence of burn in, but in many cases changes are not permanent. Getting used a new set of headphones (new to you) also needs time. There is not proven link between actual cases of burn in, temporary or not and what is heard as a change over time.

post #169 of 261
Quote:
Originally Posted by Prog Rock Man View Post

This is from a forum where part of a book available on Amazon has been quoted. It again shows that once speakers have been used they can take a significant length of time to return to their original state and one of them did not quite make it.

 

http://www.thecarversite.com/yetanotherforum/default.aspx?g=posts&t=2232

 

So my new theory of headphone burn in (with added proof) is that headphone's either do indeed burn in (but it is not necessarily permanent) or they do not burn in.

 

If left long enough between listens, the effects of burn in may have totally disappeared. How long is long? From a few seconds to days. Some headphones may not return to their original state, so can be said to have truly burned in. Some cannot be burned in as they keep quickly returning to their original state. Some are half way houses where, if used regularly may never get a chance to return to their original state. But if used occasionally they do have time to return to their original state.

 

Which headphone is which, I have no idea.

Interesting study, but the data is obviously not transferable to headphones.  The study should be done with headphones if that's where the interest is.
 

post #170 of 261

Like I said, of all the phones I've heard only perhaps 5-6 had clearly audible changes and to varying degrees w/ different anomalies.  Granted my ears only work for me and cannot provide anyone else w/ any sort of respectable scientific data.  I can however apply consistent scientific methodology to how I listen to phones out of the box and how I burn them in.  That is how I collect my experiential data.  Again, only useful to me.  So my experience is consistent w/ your prior post at least w/ respect to the low ratio to which the results are apparent.  I cannot speak to your posts causation correlating to my personal experiences of course, that would be speculative.  I think headphones and IEMs can be more sophisticated systems than mere appearances let on.  Not one study in this thread has considered enough variables to yield conclusive results IMO.  They end up amounting to scientific sound bites supported by a few data points.  This is what perpetuates the "AH HAH!!  I know more than you!" gotcha attitude so prevalent in many of the controversial 'science' threads.  The problem in approaching this experimentally is the consideration that the physiology of the ear and brain change during use as the speaker would as well.  You now have 3 dynamic variables to consider along w/ the psychology of the test subject.  Good luck, I hope you are getting paid for this.         


Edited by Anaxilus - 8/29/10 at 11:02am
post #171 of 261
Thread Starter 

Sadly I cannot find anything on headphone speakers or even tweeters. It is all woofers, presumably because they measure the biggest changes?

post #172 of 261
Quote:
Originally Posted by Prog Rock Man View Post

Sadly I cannot find anything on headphone speakers or even tweeters. It is all woofers, presumably because they measure the biggest changes?


I would guess so, since they have the most cone excursion and use the most power.  It would make sense that they do in fact change more, or are more likely to change their properties as they are used.

post #173 of 261
Thread Starter 

So, is it reasonable to assume that the far smaller headphone speaker will move less and any equivalent measurements will be smaller again.

post #174 of 261

Such assumptions may, on the surface, seen reasonable, and comprehensive, but there's more to the story that must be considered.

 

Motion is only one of many factors involved with "burn in" changes.  A comprehensive understanding of materials sciences should be considered when one examines potential "burn-in" phenomena.  With earphone and headphone drivers, generally, the cone material and the "surround" are made of the same material and must perform a dual function.

 

The surface of the cone must be as stiff as possible and as low in mass as possible, while the surround must be as flexible as possible.  The entire suspended mass must be as resonance free as possible all at the same time.  Additionally, in a conventional speaker, a "spider" is used to help center the voice coil in the magnetic gap.  In a headphone driver, in order to keep moving mass at a minimum, the surround of the driver also functions as the vc centering mechanism, instead of there being a separate spider.

 

There is much more potential for break-in phenomena to occur given the greater proportion of mechanical strength/stiffness/elasticity of the driver surround to the mass and magnetic strength of the driver itself.

 

There are a number of other factors to consider when evaluating the potential for break-in, but this is the big one. 

post #175 of 261
Quote:
Originally Posted by kwkarth View Post

Such assumptions may, on the surface, seen reasonable, and comprehensive, but there's more to the story that must be considered.

 

Motion is only one of many factors involved with "burn in" changes.  A comprehensive understanding of materials sciences should be considered when one examines potential "burn-in" phenomena.  With earphone and headphone drivers, generally, the cone material and the "surround" are made of the same material and must perform a dual function.

 

The surface of the cone must be as stiff as possible and as low in mass as possible, while the surround must be as flexible as possible.  The entire suspended mass must be as resonance free as possible all at the same time.  Additionally, in a conventional speaker, a "spider" is used to help center the voice coil in the magnetic gap.  In a headphone driver, in order to keep moving mass at a minimum, the surround of the driver also functions as the vc centering mechanism, instead of there being a separate spider.

 

There is much more potential for break-in phenomena to occur given the greater proportion of mechanical strength/stiffness/elasticity of the driver surround to the mass and magnetic strength of the driver itself.

 

There are a number of other factors to consider when evaluating the potential for break-in, but this is the big one. 


And in the end, as with all other hot topics in this hobby, is it audible?

post #176 of 261

Break-in of speakers – especially woofers – is a well-known and easily measurable phenomenon. Denying it makes no sense. At best one can ask oneself if it is audible or transferrable to headphones. But on the background of the many reports of corresponding behavior even this attempt is a bit questionable. In my experience most headphones show some sonic changes during the first 100-200 hours. The HD 800 is one of the more conspicuous candidates; in a comparison between my friend's new and my used pair the former showed the same unrefinement I experienced with my own pair at this stage (the final comparison with the new pair with ~200 hours is still on the to-do list). Even if it's reasonable to postulate a mental acclimatization to a new sonic characteristic, break-in remains a valid (alternative/parallel) scenario which moreover seems to get confirmed by said example.

 

My theory as to why headphones appear to break in

 

A lowering of the resonance frequency due to increasing compliance is a logical consequence of a headphone in use. The direct sonic effect may be a slightly lower low-frequency cut-off and/or a lower resonance peak, thus better transient reponse in this region. But this component may be of secondary importance compared to another postulated phenomenon: A stiff and brittle suspension can be the cause of a jagged compliance curve, thus an irregular membrane movement. Metrologically it will appear as increased (dis)harmonic distortion – maybe it's necessary to include measurements of non-integer multiples of the basic frequency to grasp the whole distortion spectrum.

.

post #177 of 261

I'm surprised the crew at HeadRoom never took the chance to run their tests on some well-worn headphones to see if any measure different than their new counterparts.

 

I'm also surprised that no one ever complains that a headphone sounds worse with 200 hours on it than it did when it shipped new from the factory.

 

Finally, I'm curious, do you all actually log the hours on your equipment?

post #178 of 261

 

Originally Posted by wgb113 View Post

I'm surprised the crew at HeadRoom never took the chance to run their tests on some well-worn headphones to see if any measure different than their new counterparts.


From what I know they did test different headphones new and used – but only with respect to amplitude response.
 

I'm also surprised that no one ever complains that a headphone sounds worse with 200 hours on it than it did when it shipped new from the factory.

 

My above hypothesis explains why.

 

Finally, I'm curious, do you all actually log the hours on your equipment?

 

 Only the one under suspicion and within the first 200 hours or so (in my case).

.

post #179 of 261
Quote:
Originally Posted by JaZZ View Post

Break-in of speakers – especially woofers – is a well-known and easily measurable phenomenon. Denying it makes no sense. At best one can ask oneself if it is audible or transferrable to headphones. But on the background of the many reports of corresponding behavior even this attempt is a bit questionable. In my experience most headphones show some sonic changes during the first 100-200 hours. The HD 800 is one of the more conspicuous candidates; in a comparison between my friend's new and my used pair the former showed the same unrefinement I experienced with my own pair at this stage (the final comparison with the new pair with ~200 hours is still on the to-do list). Even if it's reasonable to postulate a mental acclimatization to a new sonic characteristic, break-in remains a valid (alternative/parallel) scenario which moreover seems to get confirmed by said example.

 

My theory as to why headphones appear to break in

 

A lowering of the resonance frequency due to increasing compliance is a logical consequence of a headphone in use. The direct sonic effect may be a slightly lower low-frequency cut-off and/or a lower resonance peak, thus better transient reponse in this region. But this component may be of secondary importance compared to another postulated phenomenon: A stiff and brittle suspension can be the cause of a jagged compliance curve, thus an irregular membrane movement. Metrologically it will appear as increased (dis)harmonic distortion – maybe it's necessary to include measurements of non-integer multiples of the basic frequency to grasp the whole distortion spectrum.

.


Your reasoning makes sense.

post #180 of 261
Quote:
Originally Posted by wgb113 View Post

And in the end, as with all other hot topics in this hobby, is it audible?


In some cases, yes, in some cases, no.

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