Burn in time, myth or fact???
Jun 6, 2018 at 11:37 AM Post #46 of 67
To the OP and others about burn in.

BURN IN is a physical prove-able fact to a degree.

So what is burning in? It is normal wear and tear on a moving part. That's it. So what does burn in do for a speaker diaphragm. Now THAT is the AH-HAH! moment. Some speakers it does very little and some it does a lot. This is why some claim it is a myth and others a fact. So the answer to question of why is works on some diaphragms and not others is due to how those diaphragms are made.

Let's start with dynamic drivers since they are the easiest to explain. A dynamic driver is a "cone" of material attached to a voice coil set inside a magnet assembly. The voice coil gets alternating current at various amplitudes and frequencies. As the current changes, the voice coil generates a magnetic field around it with an alternating polarity in relation to the current. The strength, speed, and polatiry of the field generated by the voice coil is acted upon by the magnet assembly surrounding it which forces the voice coil to move in relation to that magnet. That movement also moves the cone diaphragm which moves the air next to the cone to produce sound waves. Then we get sound!

With the basics out of the way, the nuances occur. One thing is that the voice coil assembly is smaller that the cone. This can cause the inside of the cone to be moving in a direction opposite to the outside of the cone. When the inner part of the cone is moving in a different direction than the outer part of the cone it will cause audible distortions. To prevent that, most diaphragms in a dynamic speaker are coated with a very hard substance with just enough flexibility as to not crack the cone as it moves. Common substances are titanium and graphene. Here is where we get into the nitty gritty of burn in. As the driver moves back and forth, those substances are still going to break down and not be as rigid anymore. This will "loosen" up the driver which tends to warm up the sound signature a little bit. The amount all depends on how the driver is constructed. The material choices, the thickness of the coating, and other factors involved all make a difference when it comes to "burn in" of a driver assembly. Some manufacturers also pre burn in their units before selling them. There are some other nuances to the "burn in" effect in wear and tear on the driver assembly making audible sound differences as user can actually hear, but the one I described above is the main one. Of course there effects of wear and tear on planar and electrostatics as well. Usually burn in affect on those isn't a good thing at all especially in open assemblies that can allow dust inside.

So is "burn in" real? Yes it is. Are you going to experience an audible difference from burn in with every speaker or headphone assembly? The answer to that is it depends. Some you will and some you won't.

Burn in only effect the decay, so a very good and tight response set will not get any better and very decayinsh won't get better.


What burn in does is make the decay smoother overall so it sound more even on acoustic pressure.


Some iem can change drastically, some will not.

Some people will not hear change even after parameter shift and some hear even after no changes...
 
Jun 6, 2018 at 11:53 AM Post #47 of 67
Burn in only effect the decay, so a very good and tight response set will not get any better and very decayinsh won't get better.


What burn in does is make the decay smoother overall so it sound more even on acoustic pressure.


Some iem can change drastically, some will not.

Some people will not hear change even after parameter shift and some hear even after no changes...

Okay, lets get back to physics here. Decay is based of the physics principle of objects in motion tend to stay in motion. When the voice coil returns to neutral, the sound is meant to stop at that moment. Unfortunately, the driver cone, being a flexible material, is going to continue some micro movements. Think of it like hitting a tuning fork. Striking the fork causes it to oscillate which causes it to continue oscillating until friction through the air force it to stop. This is why if you hit a tuning fork in an absolute vacuum it will oscillate for a much longer time. Of course in a vacuum you won't hear the oscillations as there is no air for make sound waves from, but that is a different matter.

The rigidity of the cone directly affects the decay as well as as how fast to neutral the voice coil can return to. The voice coil itself also wants to stay in motion and doesn't like to be forced to stop or change direction like any other piece of matter (or anti matter) in the universe. So two factors act upon the decay response. Burn in technically does NOT positively affect decay at all. That doesn't mean it can't "sound" better with burn in, but decay is never affected positively by burn in. Burn in will increase the decay as the diaphragm coating breaks down and the voice coil loosens up a bit due. There is some minor loosening sometimes due to reduced friction in the voice coil assembly directly but so very minor it's almost immeasurable.

As I said, burn in is literally wear and tear on the whole driver assembly's moving parts which is the cone and voice coil for a dynamic driver. Nothing more and nothing less. The only audible differences caused by this is the coating material on the cone breaking down and allowing the cone to become looser in its response to more movement directions coming from the voice coil. This will cause increase decay and distortion and increased low end response. Again the amount of changes, and how fast those changes occur at all depends on the construcioon and materials used when making the speaker driver. This is literally basic physics and engineering I'm explaining here.
 
Jun 6, 2018 at 12:34 PM Post #48 of 67
I believe in burn-in. Why? Because the headband loosens up and ear pads compress over time. Running the headphones with pink noise sitting on a desk does nothing.
 
Jun 6, 2018 at 12:57 PM Post #49 of 67
Okay, lets get back to physics here. Decay is based of the physics principle of objects in motion tend to stay in motion. When the voice coil returns to neutral, the sound is meant to stop at that moment. Unfortunately, the driver cone, being a flexible material, is going to continue some micro movements. Think of it like hitting a tuning fork. Striking the fork causes it to oscillate which causes it to continue oscillating until friction through the air force it to stop. This is why if you hit a tuning fork in an absolute vacuum it will oscillate for a much longer time. Of course in a vacuum you won't hear the oscillations as there is no air for make sound waves from, but that is a different matter.

The rigidity of the cone directly affects the decay as well as as how fast to neutral the voice coil can return to. The voice coil itself also wants to stay in motion and doesn't like to be forced to stop or change direction like any other piece of matter (or anti matter) in the universe. So two factors act upon the decay response. Burn in technically does NOT positively affect decay at all. That doesn't mean it can't "sound" better with burn in, but decay is never affected positively by burn in. Burn in will increase the decay as the diaphragm coating breaks down and the voice coil loosens up a bit due. There is some minor loosening sometimes due to reduced friction in the voice coil assembly directly but so very minor it's almost immeasurable.

As I said, burn in is literally wear and tear on the whole driver assembly's moving parts which is the cone and voice coil for a dynamic driver. Nothing more and nothing less. The only audible differences caused by this is the coating material on the cone breaking down and allowing the cone to become looser in its response to more movement directions coming from the voice coil. This will cause increase decay and distortion and increased low end response. Again the amount of changes, and how fast those changes occur at all depends on the construcioon and materials used when making the speaker driver. This is literally basic physics and engineering I'm explaining here.
I said the same thing, it smoothens up the valley of decays. Well you can check that out in non reflecting room. The wear and tear of driver effects decay. The suspension stiffness reduction also effect decay.

It is just that you won't get a change from extremely tight decay driver or extremely loose decay driver.

Something near critical dampened driver shows major difference when suspe soon stiffness is eased due to burn and the sound decay is smoothened too...

Well dips in decay graph are elevated showing less dented and peaky decay response

The sound smoothens out after decay and this is proven fact.


I haven't heard anything sounding harsher after decay.


Why some people claim tightening up of response is that our brain perceive that decay simpler to calculate compared to decay with dips and peaks. So brain processing time reduces, making sound perceiving a little faster and tighter(this only happens in items and headphone).

Speaker burn in experience only tells more rumble and better resolved mids....


Bro... You are right but I have done my research... I was intern at sonion, so I got all that knowledge from there.
 
Jun 6, 2018 at 1:04 PM Post #50 of 67
LoL....true
I believe in burn-in. Why? Because the headband loosens up and ear pads compress over time. Running the headphones with pink noise sitting on a desk does nothing.

But, first check the impedance graph, point out the impedance peaks of your setup first..

Burn your device with those frequency.... Only that effects.


Pink noise is a log noise consisting all frequency and is lengthy process as you have to drive at lower volume because it can crack and damage your drivers.

Burn in means nothing but loosening of driver parts where they are stiff.

If you burn your device, you only reach the ideal companies reference mark..


Burn in effects over damped drivers.

If your impedance shows 45hz and 6khz.. Take those two sample tone and use them to burn it.

The driver will burn quicker and reducing stiffness from there will lead to extension to lower and higher side..


Fs can be lowered by 8hz and peak frequency can be smoothened out....


That's all

pink noise are for those who can't measure their impedance graphs.
 
Jun 6, 2018 at 5:11 PM Post #52 of 67
To the OP and others about burn in.

BURN IN is a physical prove-able fact to a degree.

So what is burning in? It is normal wear and tear on a moving part. That's it. So what does burn in do for a speaker diaphragm. Now THAT is the AH-HAH! moment. Some speakers it does very little and some it does a lot. This is why some claim it is a myth and others a fact. So the answer to question of why is works on some diaphragms and not others is due to how those diaphragms are made.

Let's start with dynamic drivers since they are the easiest to explain. A dynamic driver is a "cone" of material attached to a voice coil set inside a magnet assembly. The voice coil gets alternating current at various amplitudes and frequencies. As the current changes, the voice coil generates a magnetic field around it with an alternating polarity in relation to the current. The strength, speed, and polatiry of the field generated by the voice coil is acted upon by the magnet assembly surrounding it which forces the voice coil to move in relation to that magnet. That movement also moves the cone diaphragm which moves the air next to the cone to produce sound waves. Then we get sound!

With the basics out of the way, the nuances occur. One thing is that the voice coil assembly is smaller that the cone. This can cause the inside of the cone to be moving in a direction opposite to the outside of the cone. When the inner part of the cone is moving in a different direction than the outer part of the cone it will cause audible distortions. To prevent that, most diaphragms in a dynamic speaker are coated with a very hard substance with just enough flexibility as to not crack the cone as it moves. Common substances are titanium and graphene. Here is where we get into the nitty gritty of burn in. As the driver moves back and forth, those substances are still going to break down and not be as rigid anymore. This will "loosen" up the driver which tends to warm up the sound signature a little bit. The amount all depends on how the driver is constructed. The material choices, the thickness of the coating, and other factors involved all make a difference when it comes to "burn in" of a driver assembly. Some manufacturers also pre burn in their units before selling them. There are some other nuances to the "burn in" effect in wear and tear on the driver assembly making audible sound differences as user can actually hear, but the one I described above is the main one. Of course there effects of wear and tear on planar and electrostatics as well. Usually burn in affect on those isn't a good thing at all especially in open assemblies that can allow dust inside.

So is "burn in" real? Yes it is. Are you going to experience an audible difference from burn in with every speaker or headphone assembly? The answer to that is it depends. Some you will and some you won't.
Can you also explain why "burn-in" is always seen as positive and never negative? Like, if a headphone was great right out of the box with just the sound you wanted, and then broke in and got smoother or warmer or brighter and you didn't want that to happen?
 
Jun 6, 2018 at 7:49 PM Post #53 of 67
If you don't like it or think it's been done to death, don't read it.
too late for that i'm afraid. the point you are missing or ignoring is this topic has been raised repeatedly in threads and discussed ad nauseam for as long as i can remember. the appropriate forum for this interminable discussion is the sound science forum - not this one.
 
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Jun 6, 2018 at 7:57 PM Post #54 of 67
In order to be fact, there must be supporting evidence.

Of course we have the right to believe what we want, but also good to question what is going on as well. Because one may think their perception is absolute reality.
 
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Jun 6, 2018 at 8:24 PM Post #55 of 67
Can you also explain why "burn-in" is always seen as positive and never negative? Like, if a headphone was great right out of the box with just the sound you wanted, and then broke in and got smoother or warmer or brighter and you didn't want that to happen?

Well I experienced burn-in/break-in turning things for the worse on more than one headphone, but one stood out. The K240 Studio/MKII, it always seemed to gain horrible treble sharpness after break in which wasn't that bad when new, this was the case with 3 different pairs.
 
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Jun 6, 2018 at 8:28 PM Post #56 of 67
Can you also explain why "burn-in" is always seen as positive and never negative? Like, if a headphone was great right out of the box with just the sound you wanted, and then broke in and got smoother or warmer or brighter and you didn't want that to happen?

I can give my opinion on that, but I don't believe burn in is always beneficial to the sound at all. My explanation previously about what burn in is, being normal wear and tear that can cause sound changes, is purely a physics fact based explanation of what it is. Now as for why many like the sound after broken in and not before, that is a pure conjecture opinion there. As @dhruvmeena96 pointed out, sometimes the burn in will cause the response to be less peaky and smoother sounding with faster transitions in the music. It does introduce extra harmonic distortion though as well, which many people are probably unintentionally used to hearing and liking. It's not the same level of distortion as when some person puts a 500 watt walmart sub in their hatchback ricer and cranks the volume to the max. It's a resonance distortion that to many people used to hearing would sound natural to them if they are used to hearing that. At least that is what I think. There is also the whole head burn in thing where people get used to something over time. Also the real effect when it comes to people is when someone buys something, they WANT to like whatever it is they bought usually.
 
Jun 6, 2018 at 9:47 PM Post #57 of 67
Well there are proofs on speaker driver and subwoofers. There are no proof for iem, earbuds or headphone though.

Due to constant movement, parts of driver goes into molecular exhaustion.


But new age drivers are very advanced compared to old age lowthers like driver.


Actually when we say pink noise, it was actually a burn method for everyone and you cannot expect a result with it that's why I wrote a custom way of burning(which still cannot be 100% accurate technically).

Burn in is flattening the peaks of driver in frequency impedance graphs to ideal level.


First get to know about the frequency which is having higher impedance. Sort of peak, burn that frequency and parameters will start moving towards ideal parameters.

First 24hrs are quickest and we reach to ideal value faster.

But my suggestion is maximum 50hrs of burn. Not more than that as it is wasting of time. If thing sounds same after 50hrs then there is no use of burning it.

(This process has to be continuous and at a volume where clipping doesn't exist, sort of safe limit volume for independent frequency)

Pink noise etc takes huge time as all freq are playing in a noise format so we have to keep low volume for driver safety
 
Jun 7, 2018 at 3:31 PM Post #58 of 67
rd3-pre-burn.png


rd3-post-burn1.png



See burn in effects the response.


I don't think it is a myth anymore.

Just that extremely advanced diaphgram or rigid one takes forever to burn...
 
Jun 7, 2018 at 4:00 PM Post #59 of 67
rd3-pre-burn.png


rd3-post-burn1.png



See burn in effects the response.


I don't think it is a myth anymore.

Just that extremely advanced diaphgram or rigid one takes forever to burn...


Any background info on how that test was done, particularly whether the IEM was kept inserted in the measuring device the entire time?

Also just noticed that the tests were done at very different volume levels - the first test appears to be done with a signal about 40db louder than the second. I'm skeptical that the controls were in place here to support the assertion that this single example is "proof of burn in".
 
Jun 7, 2018 at 4:37 PM Post #60 of 67
Do you think that when they burned in, the overall level dropped 40dB?

I don't.
 

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