Audio earphones burn in doubts

[max8842]

hello ,
i purchased soundmagic E10 yesterday.
i was wondering about the burn in period.
1. how much burn in time should i give these per day .. can i give them 9-10 hours per day to burn ??
2.can i listen to the new earphones stright away for longer periods..like 8-9 hours a day??
3. for how many hours can i play them at a stretch before giving them a break ..

actually i have been looking for E10 for quite some time.n luckily landed onto these while looking for a hard disk . and as these are sparse species m pretty carefull with thwm.
rhnx

 

[gunnerwholelife]

I would strongly advice you to not burn them.Since you had been looking for these for a quite a longtime I would suggest experiencing the change in signature normally.If you still want to try the burn-in phase you go the pink noise/frequency sweeps way or just play your favourite songs on loop for say 6-7 hours.Also put in a resting period clip in between [say 30-60 secs of silence ] the files to relax the drivers. If I were you and I wanted to do a burn-in I would play my favourite songs on loop

 

[Brendon]

^^ Why do you recommend against buring in the earphones ? :S

I got a loaner pair of Signature Acoustics C12 IEMs and if I listened to them for even 15 minutes I would get a headache ! After 40 hours of burn in they have become much smoother now and the difference in sound is very noticeable from the stock condition.

Now not all earphones 'burn-in' and some sound pretty much the same right from the get go till even 1000 hours of listening.

I generally play some heavy bass tracks in a loop overnight and give them rest during the day.

 

[mjumrani]

100 hours of burn in is recommended I think. A mixture of pink and white noise with tests in the middle for the drivers.

Most earphones benefit from that except some brainwavz models.

 

[6pack]

there is no such thing as burn in imo. i went through all this burn in stuff on my soundmagic pl20 or 21 earphones a couple of years back. it used to sound as bad tin foil. after the supposed burning in of 100-150 hours, it sounded ok, but not great. after a month or two of only listening to it it sounded great. probably because my ears got accustomed and made changes in my brains internal system to receive sound from this earphone. i stopped listening to the earphones completely after a few months. after about two years, when i decided to give them a try again, they sounded exactly like they did the first time i heard when they came out of the box brand new - like tin foil.

goos speakers sound good from the moment they are on. they dont need any burnin or any gimmicks. its just a placebo effect or probably time required by your brain to get accustomed to the sound source. over time, any speaker will sound good to your ears, if you listen from it regularly.

 

[Brendon]

^^ Ok explain this. I heard the Signature Acoustics C12 for maybe 15 minutes and I literally had a headache ! Felt the treble was a bit too sharp and the bass too boomy. If you could take a video of my face you would see it cringing as I am very susceptible to any sharp peaks in the treble range (which is why I simply cannot use certain earphones with sharp treble).

Then I burned it in for 40 hours without having listened to it for even 1 minute when it was being burned in.

Now I have just used it for 1 hour and its become far smoother and I can safely enjoy it for much longer periods as well. Did I suddenly become immune to treble sharpness ?

As I said not all earphones 'burn-in'. I received a RHA Audio earphone also recently and decided to burnin in for 30 hours. I simply can't find any audio differences whatsoever since I first heard it so I can safely say that it doesn't show any burn-in. Quite a few of my existing earphones sound the same even after burning them in but a few do show burn in like the C12 and that is no imagination of mine as I have actually compared a burned in version with a non burned in version and there is a difference.

But as I said it differs from earphone to earphone. You shouldn't make a statement disproving a theory after using just one earphone !

 

[max8842]

also i have 1 more doubt..i tried all the eartips.. n the ones which fitted my ear have a comparatively smaller audio gap or hole..if u can get me..
i was wondering if that gap matters or not..??

 

[Brendon]

Different eartips affect the sound slightly depending on the design of the earphone. However the difference varies according to the IEM.

 

[esanthosh]

Inside your ear, outside your ear, an IEM will 'burn in' with usage. If you burn-in inside your ear, your brain will also 'burn' itself to the signature . Most people 'burn in' outside their ear when there is an issue with the IEM's signature in the first place. If you do not find any, just listen to your favorite music.

also i have 1 more doubt..i tried all the eartips.. n the ones which fitted my ear have a comparatively smaller audio gap or hole..if u can get me..
i was wondering if that gap matters or not..??

I think you mean the tip's opening size. It depends heavily on the IEM. Some IEMs sound better with deeper insertion (Etymotic), some IEMs sound better with tips that have a wide opening (like UE tips), some with narrow opening ones, some do better with longer tips / bi-flanges / tri-flanges, some with foam tips. You can do this 'tip rolling' all day. But, the most important thing is to find a tip that fits your ear well, rest is just for fun.

 

[mjumrani]

Inside your ear, outside your ear, an IEM will 'burn in' with usage. If you burn-in inside your ear, your brain will also 'burn' itself to the signature . Most people 'burn in' outside their ear when there is an issue with the IEM's signature in the first place. If you do not find any, just listen to your favorite music.



I think you mean the tip's opening size. It depends heavily on the IEM. Some IEMs sound better with deeper insertion (Etymotic), some IEMs sound better with tips that have a wide opening (like UE tips), some with narrow opening ones, some do better with longer tips / bi-flanges / tri-flanges, some with foam tips. You can do this 'tip rolling' all day. But, the most important thing is to find a tip that fits your ear well, rest is just for fun.

The burn if for driver is to flex it up for most frequencies. It's got nothing to do with inside or outside your ear or burn in the sound signature into your brain.

It helps many IEMs, some it doesn't effect. So rather do it than not

 

[6pack]

^^ Ok explain this. I heard the Signature Acoustics C12 for maybe 15 minutes and I literally had a headache ! Felt the treble was a bit too sharp and the bass too boomy. If you could take a video of my face you would see it cringing as I am very susceptible to any sharp peaks in the treble range (which is why I simply cannot use certain earphones with sharp treble).

Then I burned it in for 40 hours without having listened to it for even 1 minute when it was being burned in.

Now I have just used it for 1 hour and its become far smoother and I can safely enjoy it for much longer periods as well. Did I suddenly become immune to treble sharpness ?

As I said not all earphones 'burn-in'. I received a RHA Audio earphone also recently and decided to burnin in for 30 hours. I simply can't find any audio differences whatsoever since I first heard it so I can safely say that it doesn't show any burn-in. Quite a few of my existing earphones sound the same even after burning them in but a few do show burn in like the C12 and that is no imagination of mine as I have actually compared a burned in version with a non burned in version and there is a difference.

But as I said it differs from earphone to earphone. You shouldn't make a statement disproving a theory after using just one earphone !

Its not just one earphone, i've been using a myriad of earphones which audiophiles like you shun. you audiophiles only tell about high end earphones, whereas people like me use the budget earphones available to everyone. If you want a list of earphones/headphones which i've used for some time, they're panasonic, philips, sony, cowon, soundmagic, & some unknown chinese brands which you get locally for 40 bucks. All of these sound exactly the same as they did from when they were taken outside the box. Getting some funky sound from an expensive model and supposedly burning it and not getting that sound again, means you have experienced some type of placebo effect in you. Just because you get a headache and it goes away after running the earphone for 40 hours means nothing. It has no scientific basis to it. All your proof comes from what you thought you felt. No offense to you mate.
Similarly, the converse can be held true to me since my opinion comes from all the proof i heard.

I've read on some manufacturer's site that drivers always perform to their best from when they're factory fitted. Each speaker is always tested for all sound frequencies, and running them for 100 hours or so wont loosen or tighten them or give any changes in sound coming from them. If this (burnin) was actually true, why dont the manufacturer's themselves burnin the speakers before selling them?I mean everyone would like their speakers to sound better than the competition, right?
Technology now has advanced as much to put a full range of audio signals through speakers so as to loosen the drivers in all frequencies. They could run the speaker through the full spectrum from 0-25 Khz for just 1/2 - 1 hour. It would produce more results than if you played the same song for days since the song only has limited frequencies encoded in it.

 

[Brendon]

You claim my methods are unscientific but you try to disprove a theory by doing unscientific tests yourself and claim otherwise ? LP

Its not just one earphone, i've been using a myriad of earphones which audiophiles like you shun. you audiophiles only tell about high end earphones, whereas people like me use the budget earphones available to everyone. If you want a list of earphones/headphones which i've used for some time, they're panasonic, philips, sony, cowon, soundmagic, & some unknown chinese brands which you get locally for 40 bucks.

First off I am no audiophile. My collection of earphones are mostly in the 2k to 3k bracket which is a far cry from the top tier stuff that real audiophiles use.

All of these sound exactly the same as they did from when they were taken outside the box. Getting some funky sound from an expensive model and supposedly burning it and not getting that sound again, means you have experienced some type of placebo effect in you. Just because you get a headache and it goes away after running the earphone for 40 hours means nothing. It has no scientific basis to it. All your proof comes from what you thought you felt. No offense to you mate.
Similarly, the converse can be held true to me since my opinion comes from all the proof i heard.

By using your logic, if I fish in the sea and catch a fish I can conclude that fish do exist. If you fish in the sea and catch nothing then do you conclude that there are no fish in the sea ?

Most reviewers I trust also have come to the same conclusions, some earphones that we have both tested show burn-in and some (again that we all tested) did not show any changes to the sound after burn-in. Mass placebo perhaps ???

I have 6 earphones with me right now - Idance X202 and X104, Head-direct RE1, Brainwavz M3, RHA Audio m350i and Brainwavz Beta Pro,

Of the 6, only the Beta Pro showed some changes in SQ after burn-in but it wasn't very different from stock. The other 5 sounded the same after burning them for hours and hours or its possible the differences were too slight for me to distinguish.

So the percentage of headphones that have changed after burnin is very small.

The Signature Acoustic earphones I received sounded horrible out of the box and I even remarked to my friend that I couldn't bear to listen to it during the initial period. However now they are one of my favourite earphones. It must be some strong placebo effect to make a hated earphone transform into one of my favourites.

I've read on some manufacturer's site that drivers always perform to their best from when they're factory fitted. Each speaker is always tested for all sound frequencies, and running them for 100 hours or so wont loosen or tighten them or give any changes in sound coming from them. If this (burnin) was actually true, why dont the manufacturer's themselves burnin the speakers before selling them?I mean everyone would like their speakers to sound better than the competition, right?
Technology now has advanced as much to put a full range of audio signals through speakers so as to loosen the drivers in all frequencies. They could run the speaker through the full spectrum from 0-25 Khz for just 1/2 - 1 hour. It would produce more results than if you played the same song for days since the song only has limited frequencies encoded in it.

Are you so niaeve to believe that a Chinese earphone manufacturer selling millions of earphones actually bothers to test each earphone for burn-in ? I would not be surprised if there wasn't even a customary DOA check to see if the earphones worked or not with many Chinese manufacturers.

Only better companies like Etymotic ears or AKG or Sennheiser might bother testing each earphone.

I trust my ears and I have had 2 earphones from the same manufacturer and one was burned in and one wasn't. (Hippo VB). My friends copy was brand new and mine was almost a year old. His copy was noticeably more sibilant than mine and I could easily tell the difference.
If you believe that all manufacturers test and burn in earphones including the cheaper ones you use then fine.

These aren't scientific tests a of course but I believe my ears and common sense tells me that if 10s of other reviewers also agree with me that one earphone experiences burn-in while another model does not I am more inclined to believe that than someone who uses a few earphones and comes to the conclusion that they sound the same after usage and hence the burn-in phenomenon doesn't exist !!!

Mind you burn-in isnt going to make a $10 earphone suddenly compete with a $100 earphone. Its a subtle but audible difference. Bass tightening, treble smoothing etc. If you don't have a ear for such differences you will not be able to tell any difference.

Lastly have a look at this and come to your own conclusions - http://www.innerfidelity.com/content/evidence-headphone-break

This is one headphone that tons of people have commented that they experienced changes in the sound after burn-in. All of them must be like me suffering from mass placebo effect.

 

[esanthosh]

The burn if for driver is to flex it up for most frequencies. It's got nothing to do with inside or outside your ear or burn in the sound signature into your brain.

It helps many IEMs, some it doesn't effect. So rather do it than not

In my experience, most it doesn't affect, a handful it may have. Unless as Brendon mentioned, someone compared the fresh IEM and a burned-in IEM side by side, there's no way to trust audio memory. Even then, it can be argued that there are manufacturing differences between batches, but let's leave that fight to objectivists.

I am just agnostic to the mythical effects of burn-in. I have owned a little more than 50 IEMs so far, but have observed this change for the better in may be 4-6 IEMs. Even then, there are a couple of cases where I had made other changes at the same time i.e., switched to a different tip for listening post burn-in, so the effect may be due to tips rather than burn-in. In the rest of the cases, I thought I had heard them get better with time. I had compared them on Day 1 (within 1-2 hrs) to other IEMs and repeated the comparison after burn-in. The differences noted were similar between the two. I do not trust my audio memory at all. So, I cannot say whether 100 hours prior, 5-6 Khz band was at +3dB and it was at +1.5dB after burn-in, but whatever changes occurred were minor enough not to affect the general difference between the compared IEMs be it bass quantity, mid forwardness, treble hotness and such.

I did burn-in every IEM I ever owned for at least 50, if not 100 or more hours (some for 300 hours) because

a) I invariably wrote impressions. Most impressions are implicitly done post burn-in. When you are in Rome....

b) It did not cost me money. Just a few minutes when starting and a few when ending each session. I had exclusive portable players for burn-in (4 at one point), so there was no disturbance to my regular listening using other IEMs either.

Can someone hear burn-in differences? I don't know. I can only say I haven't. It depends heavily on the hearing ability (Frequency range, the ability to discern small differences - someone who can hear a 0.5dB difference is obviously better than someone who cannot differentiate below 1dB), concentration (knowing which parts are likely to sound different) and other such things.

Tyll's two posts:

A subjectivist view: http://www.innerfidelity.com/content/testing-audibility-break-effects

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

His conclusions were different too...

Have we absolutely proven that break-in is an audible phenomenon? No. All I've proven is that I could tell one headphone from another. Proof positive is not easy to come by, and it's not something to claim lightly. However, I think this test moves us strongly in that direction.

My experience with Q701 (and K701) headphones tells me the differences I was hearing were very much like what I've experienced in the past. The characteristic I was listening for was essentially that the broken-in pair delivered a smoother listening experience, and the new pair had an edge to them that made me wince. It was that difference in the listening experience I perceived during the tests. That doesn't rule out that the two headphones may have just sounded different in that way from the manufacturer, but I doubt it.

It's clear to me, having had the experience, that there is indeed an audible difference when breaking-in a pair of Q701 headphones. I've seen measured differences, and now experienced audible differences. While the measured differences are small, I believe the human perceptual system is exquisite and able to perceive, sometimes consciously and sometimes sub-consciously, subtle differences.

Until then, you can unbox you new headphones and have a listen without angst. You'll be hearing pretty much how they will forever sound. If you notice they're a bit irritating in the mid-treble, you might find that settles out somewhat with use and the headphones may deliver a mildly more pleasant listening experience.


If you do want to break-in your cans, I suggest pink noise at a slightly louder than normal listening level. If you don't have a pink noise track, just play music. If they sound lousy out of the box, but they start sounding a lot better as you listen to them over time, it's your amazingly versatile brain figuring out how to cope with the world.

The miracle is in your head ... not in the headphones.

 

[6pack]

You claim my methods are unscientific but you try to disprove a theory by doing unscientific tests yourself and claim otherwise ? LP

First off I am no audiophile. My collection of earphones are mostly in the 2k to 3k bracket which is a far cry from the top tier stuff that real audiophiles use.

By using your logic, if I fish in the sea and catch a fish I can conclude that fish do exist. If you fish in the sea and catch nothing then do you conclude that there are no fish in the sea ?

Most reviewers I trust also have come to the same conclusions, some earphones that we have both tested show burn-in and some (again that we all tested) did not show any changes to the sound after burn-in. Mass placebo perhaps ???

I have 6 earphones with me right now - Idance X202 and X104, Head-direct RE1, Brainwavz M3, RHA Audio m350i and Brainwavz Beta Pro,

Of the 6, only the Beta Pro showed some changes in SQ after burn-in but it wasn't very different from stock. The other 5 sounded the same after burning them for hours and hours or its possible the differences were too slight for me to distinguish.

So the percentage of headphones that have changed after burnin is very small.

The Signature Acoustic earphones I received sounded horrible out of the box and I even remarked to my friend that I couldn't bear to listen to it during the initial period. However now they are one of my favourite earphones. It must be some strong placebo effect to make a hated earphone transform into one of my favourites.

well i mentioned it was my opinion and my experience in the very beginning. you dont have to believe it or take it for granted. what i may experience with my ears may not work out for you or anyone since my brain will be wired differently. If you and your trusted reviewers have come to the same conclusion - good for you guys. It does not mean non-believers have to believe in it.

Are you so niaeve to believe that a Chinese earphone manufacturer selling millions of earphones actually bothers to test each earphone for burn-in ? I would not be surprised if there wasn't even a customary DOA check to see if the earphones worked or not with many Chinese manufacturers.

Its nice to see you have selectively singled out Chinese audio makers when my list had manufacturers from a lot of different countries.

Only better companies like Etymotic ears or AKG or Sennheiser might bother testing each earphone.

I trust my ears and I have had 2 earphones from the same manufacturer and one was burned in and one wasn't. (Hippo VB). My friends copy was brand new and mine was almost a year old. His copy was noticeably more sibilant than mine and I could easily tell the difference.
If you believe that all manufacturers test and burn in earphones including the cheaper ones you use then fine.

These aren't scientific tests a of course but I believe my ears and common sense tells me that if 10s of other reviewers also agree with me that one earphone experiences burn-in while another model does not I am more inclined to believe that than someone who uses a few earphones and comes to the conclusion that they sound the same after usage and hence the burn-in phenomenon doesn't exist !!!

Mind you burn-in isnt going to make a $10 earphone suddenly compete with a $100 earphone. Its a subtle but audible difference. Bass tightening, treble smoothing etc. If you don't have a ear for such differences you will not be able to tell any difference.

Did i say that? i never said a 10 dollar earphone will outshine a 100 dollar earphone anywhere in my posts. you're just making stuff up now.
i only said that they didnt sound any different than when they were newly bought. even after a few years of use.
How is it that burnin only makes sound better according to you people? why doesn't it make a earphone or speaker sound more worse? it should be both, if you look at it logically.
And also its funny that you say you will believe 10 people who will agree burnin happens while you will disagree with the rest. Whatever floats your boat.

Lastly have a look at this and come to your own conclusions - http://www.innerfidelity.com/content/evidence-headphone-break
This is one headphone that tons of people have commented that they experienced changes in the sound after burn-in. All of them must be like me suffering from mass placebo effect.

good or you people.

Thanks for the article link. I did read it. Only conclusion i can come to is it does not make any significant difference to the reviewer.
Look at his own summary

"Summary Did I show break-in exists? No. There are too many variables still. Was it simply movement? I don't know. If I did it again to another brand new pair would I get the same results? I don't know. If I did it to an already broken in pair would I get the same results? I don't know."​

So its inconclusive. This will be true for majority of speakers in all possibility.
Its interesting to know it was tested on an AKG headphone (when you mentioned that these guys bother testing their systems) and incidentally, that system seems to show some small difference in frequencies. weird isn't it?

Please read this article if possible: http://www.audioholics.com/education/loudspeaker-basics/speaker-break-in-fact-or-fiction

Anyway before you go on blasting me and quoting my every word here, lets drop this discussion and enjoy music. I was just bored and had nothing to do, so was wasting your time.

 

[Brendon]

So you make false statements against me and expect me to leave it at that ? :S

You claim I attributed a statement that a $10 earphone will compete with a $100 earphone to you !!! When I quoted your statements where did I ever claim you said that ??? I merely was trying to make a point that burn-in isn't a night and day difference.

Please show me and ill shut up immediately.

And where do you think your Cowon, Sony, Philips and Soundmagic earphones are made ??? Japan ?? . All the earphones I have even the UK based RHA audio, Japanese based Sherwood and the few Sennheiser, AKG, Iphone and other IEMs are all manufactured by some OEM in china and there is no way any of them do burn-in. Max we can expect them to do is a DOA test forget 100 hours of burn-in.

And yes, burn-in has worked both ways. The bass on the C12 has tightened up. Those who want boomy bass will not like the tightened bass. My sister for example doesn't like it as much now as when she first heard it as her music is more bass oriented while mine is more vocal oriented. Oh yes she too suffers from the same placebo effect that I suffer from though its a common placebo effect since we agree (more or less) that the sound has changed from when we first heard it.

And why should I believe those who haven't experienced burn-in when I have heard it myself not in a one off earphone but in a few earphones over the years ?

The disbelievers (like you) have not disproved burn-in. You people have merely stated you haven't experienced it which goes perfectly with my fish in the ocean argument as there isn't a scientific test to either prove or disprove burn-in.

Ill agree with you that a lot of it is conditioning by the brain but that would be the case if I listen to the same earphone for hours and hours together. This wasn't the case for me. I heard it first then burned it in and then heard it again.

In any case I am not the unreasonable one here. I don't believe in cables as I have never heard any difference between one cable and the next. However a lot of my friends claim otherwise and while I wouldn't spend on a cable I am open to the idea that it makes a difference. Just because I haven't heard any differences in the limited testing that I have done doesn't mean that the phenomenon doesn't exist.

 

[6pack]

^ your fish in the ocean logic is flawed. it has no similarity to this burnin effect you guys get.
The only similar logic i can think of is, say both of us get a can of coke from the same vending machine. You tell me after each sip that the coke is tasting better and better, whereas i say i dont find its taste being any different from the first sip. Then you say that you know people who have had the same experience while drinking coke, while I argue that its a one off experience.

Thinking more on this burnin matter, what if the manufacturer has already tested the speaker for burnin? will such a speaker get more burnin after already being eased in? Also what if the burnin is actually adjustments made by the mind towards receiving sound from a particular speaker. Example. I have a couple of headphones A and B. I listen to A for a few months. By this time my mind is thoroughly accustomed to sound signature of A. B is brand new and never been used. After playing B for the first time, I notice it being quite different and not to expectations, since my mind subconsciously compares its sound signature to A. Lets say that the sound pattern in the brain when its listening to A does not match the new pattern its getting from B and so it does not feel its sounding right. Subconsciously B's sound pattern is recorded into the mind now with just one hearing. Lets say i put B for burnin for a couple of hours or days. Then i listen to B and the sound pattern matches in the brain since it has already recorded it previously. To top it the brain can now adjust to the sound signature coming from B so that internally it can be made almost matching to the previous well set pattern of A or the brain makes adjustments to sound coming from B so that it matches its requirements.

If this theory is correct, then it can give a reasonable explanation as to why you did not get a headache the second time you put on your earphone. Your mind had already copied the high treble coming from the earphone and it was expecting it the next time you put it on. So it made provisions to change pattern of sound coming in so that treble is reduced. Since treble got reduced, you could hear bass and mids more better than you did the first time. Probably the first time you felt a headache was that you were listening to some other earphone or headphone which had low treble (possibly) and subconsciously it used to boost treble by some margin to equalize sound internally.

I mean I came to this conclusion after reading all those three links above which clearly show that no matter of burnin changes sound signature by a lot. Also what if these changes are just distortions made by a faulty speaker diaphragm material after being used continuously? I'm actually considering these speakers that show burnin as being faulty since they are in minority and majority of speakers do not such acoustic differences after say being played continuously for days or years.

 

[Brendon]

I agree with you the fish argument was quite ridiculous but I added it anyway for fun.

However the coke argument is also flawed since no one has ever mentioned that Coke tastes different with each sip. It tastes horrible right from start to end !!!

And yes I agree with you about your brain playing tricks with your mind. I had an RE1 earphone and I swear I could hear it sound better and better as time went on. When the earphone died I just got a new pair and lo and behold it sounded exactly like my old one !! Egg on my face !!!

This case its completely different. I am and will always be very susceptible to sharp treble. I have a Yamaha HP2 headphone that has very sharp treble. I haven't gotten used to it over time no matter how long I listen to it. I keep it around only because its sounds sublime with classical music.

I have a few tracks that I keep around to test for sibilance and the C12 fared miserably in those tests when it was new. I used the HP2 as a reference on the same track and both fared equally bad. I have listened to it now and the treble has become practically tame on the C12 but its still harsh on the HP2.

If I was using the C12 earphones over time and felt the changes then yes its highly possible my brain was getting accustomed to the sound. Its happened to me on various occasions where I don't like a earphone initially but after using it for a few hours I get used to the sound and start enjoying them.

However I have not and will not ever get used to sibilance and treble harshness no matter what unless I grow deaf (God forbid !!).

I have already stated that most earphones don't really offer any burn-in. Its happened to maybe 4 earphones out of the 15-20 that I have ever used on a regular basis so its definitely not a very common phenomenon. I will be the first to admit that I have claimed my earphones have sounded better over continuous use that have been purely a placebo effect but I have been much more careful now after the RE1 incident and I am confident that the C12 does show some burn-in.

Anyways this argument is becoming pointless. I can't convince you that burn-in exists neither am I going to budge from my viewpoint.