[BobSmith8901]

And having spent time debating this subject, before my hearing took a crap... I have come to believe both theories are true:

1) headphones change sound quality over time (whether that's called 'burn in' is irrelevant), and
2) peoples perceptions of sound quality change, for numerous reasons.

Re: 1) It's kind of obvious that any mechanical device (headphones included) will change characteristics over any given period of time. Cars, boats, planes, headphones, garden hoses, lol, whatever... (except maybe my ex wife)....

Re: 2) Hearing loss over time as we age. Or, hearing afflictions, like Meniere's disease, or simple hearing loss because of old age. Attend too many Rock concerts and, well, you know...

As proof, I offer the great number of arguments/discussions that we have had, for years.

I suggest that we may never resolve this subject, because it has no resolution...

I would agree that a person's hearing or hearing perception can change over the course of a day or even a single listening session. As I have been listening on headphones almost exclusively for the last several years, a typical session might start at, say 11:30pm, and go til around 1am. DAP and headphones, Tidal HiFi or local SD card files: At first things will sound fresh and my enjoyment is at a relatively high level. By the end of a session my neural pathways or what ever have been worn down and I almost say to myself out loud, "there's no reason to keep trying to chase it, it's over..." and I end the session. Every so often, but less than average, I end the session on an even keel with the enjoyment still at a good level, sort of the equivalent of a Senfeldian "end on a high note".

Sometimes it starts off badly and never gets better and you just have to give it up. Once in a blue moon the entire session is inspired--I remember in particular a session I had with my DAP and a set of HiFiMan HE-X4's that sounded good the entire time. I just sort of marveled at it. It could have been a sort of perfect combo of well-restedness, relaxation and mental calmness, I don't know. My hearing isn't perfect by any means so that certainly plays a part overall--hi freq hearing loss from concerts and playing guitar back in the day and Tinnitus which for me manifests in a general, low volume, very high frequency constant noise, like a low volume version of ringing ears that I mostly tune out, but is there if I'm in a silent room or have closed backs on with no music playing. On the other hand if I had lots of high-end equipment I might be singing an entirely different tune!

 

[bigshot]

Why do people always report burn in as an improvement? If the sound was changing, it would just be a change, sometimes good, sometimes not.

Why does burn in stop? It seems to me that if something can change, that would make it prone to changing more. Why wouldn’t it change after six months of use?

 

[jagwap]

Why do people always report burn in as an improvement? If the sound was changing, it would just be a change, sometimes good, sometimes not.

Why does burn in stop? It seems to me that if something can change, that would make it prone to changing more. Why wouldn’t it change after six months of use?

We discussed this also, but you forget, for whatever reason.

Burn in generally leads to improvement for two reasons:

Compliance from new heads to a consistent behaviour. The materials work themselves towards their steady state behaviour. The way they will be for the majority of the lifetime of the product. The rate of change is relatively rapid in the first few hours, and dissapears to effectively nothing over the rest of the lifetime. The eventual braking point is so far away in time, it is considered a separate process.

The people tuning the product will work on prototypes that have been used, measured and proven for many hours when they finish tuning the product. So their final design will be aligned with the steady state behaviour above, not the fresh out of the box compliance.

It's not balck magic or voodoo. Quite simple really, if you allow yourself the imagination to think it may exist for a few moments instead of deciding something from your own rationale rather than actually listening, to people or product.

 

[jagwap]

BTW, having worked for an audio manufacturer at one time, I know for a fact that they tested every device for 24 hours, before it was shipped. This was done more to ensure the product worked, than to ensure any sort of sound quality. I also participated in factory repair of units that had been poorly assembled, literally spending months repairing the same stupid defect that came from the original factory in Japan.

No, I won't be repeating the name of the company.

Yes this is common, because a significant number of failures happen in the first 24 hours, often assembly errors, sometimes component failures. This is also a well documented phenomenon, and statistically proven. This used to be unfortunately nick-named "infant mortality", but in these enlightened times the term has thankfully been dropped.

Even the Japanese make assembly errors. I imagine the error was most cosistantly wrong every time?

I have worked for audio manufactures for over 30 years, and I have seen some real crazy mistakes. I will also not be naming them, but we all know some of them.

 

[jagwap]

And having spent time debating this subject, before my hearing took a crap... I have come to believe both theories are true:

1) headphones change sound quality over time (whether that's called 'burn in' is irrelevant), and
2) peoples perceptions of sound quality change, for numerous reasons.

Re: 1) It's kind of obvious that any mechanical device (headphones included) will change characteristics over any given period of time. Cars, boats, planes, headphones, garden hoses, lol, whatever... (except maybe my ex wife)....

Re: 2) Hearing loss over time as we age. Or, hearing afflictions, like Meniere's disease, or simple hearing loss because of old age. Attend too many Rock concerts and, well, you know...

As proof, I offer the great number of arguments/discussions that we have had, for years.

I suggest that we may never resolve this subject, because it has no resolution...

You are correct on all fronts.

It is now scientific proven speakers burn in, and the debate is finally over, except for a few unbelievers (you know the type: anti-vax etc.). No one designing speakers with any real experience believe burn-in doesn't exist. However as it is the spider of the driver in a speaker that provides most of this effect, and few headphones have a spider, it is still in the "debatable" phase on most simple headphones, due to a lack of published evidence. It doesn't mean it cannot exist. The headphone experts in the company I work in diplomatically say it "depends" when asked, as it can cause so much debate, and we have to keep the customers un-offended.

I also believe the other effect is we get used to a new sound, and adjust to it. The difference here is this one works on old run-in products too.

Because both factors exist, people feel they need to choose one, and one only to exist. Daft.

 

[UmustBKidn]

You are correct on all fronts.

It is now scientific proven speakers burn in, and the debate is finally over, except for a few unbelievers (you know the type: anti-vax etc.). No one designing speakers with any real experience believe burn-in doesn't exist. However as it is the spider of the driver in a speaker that provides most of this effect, and few headphones have a spider, it is still in the "debatable" phase on most simple headphones, due to a lack of published evidence. It doesn't mean it cannot exist. The headphone experts in the company I work in diplomatically say it "depends" when asked, as it can cause so much debate, and we have to keep the customers un-offended.

I also believe the other effect is we get used to a new sound, and adjust to it. The difference here is this one works on old run-in products too.

Because both factors exist, people feel they need to choose one, and one only to exist.

I found a nice, not too long article on the various types of headphone drivers, below.
This helps underscore your points above.

https://soundgearlab.com/guide/types-of-hephone-drivers/

 

[castleofargh]

Some think a given experience about burn in is real, while others don't. That's a 50/50 chance of being correct. IMO, it's all about pets. They look cool but they actually screw up with audio gear behind people's back, causing change in sound for unsuspecting owners. It also explains why not everybody gets to have the same experience with a given model of headphone. Clearly I'm onto something here.
My position being backed up by as many facts as someone's anecdote about his headphone burning in, we should now consider 3 possibilities of equal potential.
To support my point, here's a graph I found by typing"80%" in google image:

Now you can see how whether you're convince that burn in is real, or that it's BS, your odds of being correct are only 33.33333%. Which means that at a statistical level, there's a solid 66.66666% chance that you're clearly wrong.
QED.



ps: I practice reasoning wushu.

 

[bigshot]

Monkeys are the most problematic pets because they have an opposable thumb to use to turn dials on your system when your back is turned.

The chaos theory would say that the longer you burn in, the more chance change isn't going to be beneficial to an ordered result.

I think what they did with the headphones I was consulting on was to measure each transducer and the ones closest to the target were put in the high end line. The ones that just missed the manufacturing tolerances were put in the midrange line. And the ones that were further off were put into the low end line. I asked the designer what happened with the transducers that didn't meet spec, but he wouldn't answer. I'm pretty sure that all the copies of the headphones that were sent to me were measured and stable because the prototypes had markings on them to indicate which set it was... and they specifically said burn in was a waste of time.

 

[dirtrat]

Although I have been an Audiophile for over 40 years, I've NEVER believed in burn in. I know it's not a popular opinion with Audiophiles and people seem very strongly opinionated about this. I've had people call me crazy for this belief. I have no doubts that people are hearing improvements over time. My one exception to this belief is possibly speakers and headphones since they have some mechanical properties. I've seen it first-hand where peoples hearing changes over time, and they adjust to this new sound, and it does improve. I've yet to see any real scientific and undeniable proof that would explain electronic stereo devices sound changing after burn-in. Modern electronic components have very tight tolerances, and their values would have to change significantly to impact the sound this much. Are there exceptions to this? Possibly with tubes or transformer but it's a complete guess on my part. Our hearing is very sensitive and needs to adapt to new sounds especially when you are used to hearing something a certain way. This has always been a somewhat controversial topic and always will be! AGAIN, this is just my opinion!

 

[BrownBear]

Although I have been an Audiophile for over 40 years, I've NEVER believed in burn in. I know it's not a popular opinion with Audiophiles and people seem very strongly opinionated about this. I've had people call me crazy for this belief. I have no doubts that people are hearing improvements over time. My one exception to this belief is possibly speakers and headphones since they have some mechanical properties. I've seen it first-hand where peoples hearing changes over time, and they adjust to this new sound, and it does improve. I've yet to see any real scientific and undeniable proof that would explain electronic stereo devices sound changing after burn-in. Modern electronic components have very tight tolerances, and their values would have to change significantly to impact the sound this much. Are there exceptions to this? Possibly with tubes or transformer but it's a complete guess on my part. Our hearing is very sensitive and needs to adapt to new sounds especially when you are used to hearing something a certain way. This has always been a somewhat controversial topic and always will be! AGAIN, this is just my opinion!

I also believe that hearing adjusts to different sounds and tonalities. With my own gear, I find that I have to re-adjust my hearing to a specific set of headphones after listening to a different set for a period of time. Since all my headphones are well burned in by now, it certainly can't be that that's causing my perception to change. Just my experiences though.

 

[jagwap]

Although I have been an Audiophile for over 40 years, I've NEVER believed in burn in. I know it's not a popular opinion with Audiophiles and people seem very strongly opinionated about this. I've had people call me crazy for this belief. I have no doubts that people are hearing improvements over time. My one exception to this belief is possibly speakers and headphones since they have some mechanical properties. I've seen it first-hand where peoples hearing changes over time, and they adjust to this new sound, and it does improve. I've yet to see any real scientific and undeniable proof that would explain electronic stereo devices sound changing after burn-in. Modern electronic components have very tight tolerances, and their values would have to change significantly to impact the sound this much. Are there exceptions to this? Possibly with tubes or transformer but it's a complete guess on my part. Our hearing is very sensitive and needs to adapt to new sounds especially when you are used to hearing something a certain way. This has always been a somewhat controversial topic and always will be! AGAIN, this is just my opinion!

I'm glad you are open to the possibility that there are exceptions, because there are:

All transistors have very wide gain (the order of 80-350). Even the Hfe gain band selected types. This does not tend to affect burn in much, but is the main resdon for their being a finite warm-up time in amplifiers. It also can change the amplifier's audio stability if the amp is driven hard, particularly into clipping, taking sometimes minutes to recover. Their bandwidth, input capacitance, Vbe (on voltage), and many other parameters vary wildly between samples and temperatures. This is why discrete audio design involves experience and knowledge.

Electrolytic capacitors are far from tight tollerance. The best available are 10% in terms or their capacitance, these are rarely used. +/-20 % is commonly considered high quailty, and low cost gear uses +80/-20% tollerance, which if used with abandon will result in very lose consistancy between unit. However a little known and certainly overlooked factor is that a key characteristic of theirs: ESR (Electrical Series Resistance), or how closerly they represent a low impedance at higher frequencies, changes over time. Now it is well known by professional electronic engineers that is goes up over time slowly, as the componant wears out. This is VERY slow, and generally you will only noticed the effect when you find someone whop can change these components out for new parts, say 20-40 years of use. (don't worry, the 1% capacitors that should be in you RIAA phono stage are different and super stable, if the designer knows anything.)

However, what is less common knowledge, is these same parts go through a rapid change of ESR over the first few 10s of hours after the unit is switched on. The ESR goes down as the electrolyte settles to its working voltage, which improves their performance. The change is quite significant, and I would not be surprised if some equipment it could be audible.

A competant audio designer needs to design out these factors as much as possible. However you can only attenuate the effect, and it often cost money to do so. So this can be why high end gear gets expensive, but consistantly good.

Belief is a wonderful thing, but in Sound Science it should give way to repeatable results and scientific measurement.

 

[bigshot]

I hope whatever I buy is manufactured to perform to spec out of the box. I don’t want to take a chance that it burns in to something I don’t like.

 

[jagwap]

I hope whatever I buy is manufactured to perform to spec out of the box. I don’t want to take a chance that it burns in to something I don’t like.

You're funny. Given I explained this a few comments ago

 

[LaughMoreDaily]

If underpants can be burned in. Why not audio products?

 

[bigshot]

Mine are burned out!