[dweaver]

I think because this is more like static versus say heavy drumming the sound helps to excersize and limber up the driver versus causing it to loose it's elasticity.
 
Hi Shigzeo, when I did my measurements I got significant fluctuations. What I did was continue to work to get the mic and IEm in the right spot so they had a constant reading and only used the highest reading that I could get for both IEM's.
 
Anaxilus, I'm afraid this is no imagining, the reading no matter how crude are real. To be honest I suspect with better equipment I would be getting even more variation than what I have been able to record now. I even had my wife listen to both IEM's without telling her anything about which IEM should sound and she noticed a difference between the two IEM's and described the sound differences I am noticing and believe you me she doesn't really care about all this stuff at all. What I hope is that some of you that download the file (I put up a flac version last night BTW plus a FLAC file that shifts it's focus from bass lower midrange to mids and treble as well) will see some overall improvement even in burned in Copper's as this would show this file can be used on any Coppers, not just new ones. But I do also suspect that a new pair might be more influenced by this treatment as it would shape their sound while the driver is in it's infancy so to speak.

 

[dweaver]

For kick's I just threw my HD600 on my computer and will let them burnin throughout the day and see what if anything happens to them.

 

[Anaxilus]

Quote:

I
 
Anaxilus, I'm afraid this is no imagining, the reading no matter how crude are real. 

Sadly I know it is from my years of experience, despite the 'know better than you' naysayers.  Driver shaping is a whole other can of worms.

 

[dweaver]

OK I found a better software program for measuring and testing both Coppers as well as a small microphone. I ended up using a piece of surgical tubing to join the IEM to the end of the microphone and this gives my a stable reproducable connection. There is still background noise but it's more manageable and I am also able to calibrate out most of it. This new mic goes from 20hz to 16Khz but I never noticed any changes after 16Khz anyway so my results will be limited to that. I have to understand the scale used by my program before I post the variations. Also due to having both sets measured and reproduceable easily I am now applying my burnin process to my 1st pair of Copper's to see if I can change their bass and lower midrange.

 

[Hentai11]

Interesting test protocol, and I like that it's objective and relies on something measureable.

Some other things I'd like to see:

-repetition over a large sample
-before/after tests
-a control set
-double-blind testing

Someone mentioned analysis by batch, another good idea.

Really good start, though. This is the sort of burn-in discussion to which I can listen. I would be slow, though, to draw conclusions based on a single trial on a single pair of phones.

 

[Photofan1986]

Dweaver,
 
You would like to use panasonic microphones called wm-61a (or b if you want to solder pins). Those are perfectly linear microphones which are able to pick up a frequency range from 20 to 20.000 hz almost perfectly linearly.  http://www.panasonic.com/industrial/components/pdf/em06_wm61_a_b_dne.pdf
You can find those on ebay for cheap (2 or 3 $ for one).
Anyway, if you are interested, here is a similar project, with some further explanation: http://www.johncon.com/john/wm61a/
And thanks for your findings!
Photofan

 

[dweaver]

Thanks for the information and encouragement Photofan1986, I will see if I can get the courage to try this and if not may have a resource who can help me make this microphone which sounds like it would be better for what I am doing.

 
Quote:

Dweaver,
 
You would like to use panasonic microphones called wm-61a (or b if you want to solder pins). Those are perfectly linear microphones which are able to pick up a frequency range from 20 to 20.000 hz almost perfectly linearly.  http://www.panasonic.com/industrial/components/pdf/em06_wm61_a_b_dne.pdf
You can find those on ebay for cheap (2 or 3 $ for one).
Anyway, if you are interested, here is a similar project, with some further explanation: http://www.johncon.com/john/wm61a/
And thanks for your findings!
Photofan

Thanks Henta11, I would love to be able to do what your suggesting but am not sure I will ever be set up or be able to afford what your suggesting. But can see that it is what would be necessary really test the theory out and prove out burnin as well.
 
What I will do if I am offered an opportunity to review another IEM again is see if I can get two pairs from the same batch so at least I can show demonstrative finding from two pair that should by manufacture be the same. I am note sure I know how double blind testing works but I did have my wife listen to both pairs without telling her which was which or what to look for and she was able to tell be the basic differences from the two pairs.
 
I also agree that this is to small a sample to be considered to be defacto which is partially why I have made the burnin files I used available to other users.
 
Quote:

Interesting test protocol, and I like that it's objective and relies on something measureable.

Some other things I'd like to see:

-repetition over a large sample
-before/after tests
-a control set
-double-blind testing

Someone mentioned analysis by batch, another good idea.

Really good start, though. This is the sort of burn-in discussion to which I can listen. I would be slow, though, to draw conclusions based on a single trial on a single pair of phones.

 

[koonhua90]

Dweaver, perhaps you should contact Monster and request for some samples to conduct the experiment. Based on their generosity that I have observed so far, there should be no problem requesting a few samples.

 

[dweaver]

Koonhua90, sorry no luck on getting another pair to do further testing...
 
So I tried changing my original Copper using my burnin files with no change that I could tell by listeing or by measured results. So I do not think you can change the sound of a fully burned in/used pair. This has also been coroborated by another head-fi member who I asked via PM to try this as well. (if your pair is still relatively new though this might be able to affect them slightly).
 
I want to wait another couple days before posting my final variations in DB I am getting but the bass does seem to be settled and not changing and is noticeably stonger (4-5db for 50, 100, 250hz) but the midrange is only noticeably stronger at 500hz (5db) now and slightly stronger at 1000hz (3db). The treble is almost the same now between both IEM's with only slightly stronger treble on the original pair and only at a few frequencies which does suggest the treble is still settling in but will be about the same.
 
So the burnin process only potentially affects the bass and low midrange as I originally stated but not as much I originally was seeing, so this may also be the difference between pairs. At this point I think driver shaping may not be possible or if possible is only in those two areas mentioned and is minimal.
 
What I do think is undeniable and for the first time that I know of provable via DB measuring is that burnin does exist as there has been changes in the sounds of this IEM as it broke in.

 

[2rooi123]

yeah, burned in the mtpg for 3 straight nights using your file
i used it on the 4th day and bass improved noticeably
mids were brought out a tiny bit
highs were more or less the same

 

[koonhua90]

Nothing stays unchanged as time goes by (whether you are looking from an engineer/scientist/philosopher/religion expert/average human point of view, things corrode away/get destroyed, molecules shift, energy changes), so I see no reason why someone would say that burn in does not exist. 

 

[Anaxilus]

Quote:

Nothing stays unchanged as time goes by (whether you are looking from an engineer/scientist/philosopher/religion expert/average human point of view, things corrode away/get destroyed, molecules shift, energy changes), so I see no reason why someone would say that burn in does not exist. 

People do it all the time.  Some always feel better about themselves by believing they are on to some fundamental, simplistic truth and that others are being misled by some mass marketed mythology.  I'm done explaining how speaker sound changes w/ time, that better cables can upgrade analog video and sound and that a high boost turbocharged or high-compression engine likes premium unleaded.  I'm just a fool thats misled by others to waste money.  

 

[mvw2]

Some notes:
 
Two separate products, even the same model, will always vary to a small degree.  No two drivers will be exactly the same.  No two enclosures will be exactly the same.  Any electrical components used will not have the exact same values.  There will always be slight variations, both between the left and right drivers and between different sets of the product.
 
Second, how accurate is the dB measurement using the iPhone?  Have you tested the same earphone more than once to measure any natural variation in the readings?  For example, depending on the method you could very well see 2-3dB variation with great ease.  You have to be very careful about how you test and how repeatable the process is, both in how you physically do the test (exact location and distancing to the mic) and how accurate the testing device is (iPhone variation).
 
 
A question:
 
For burn in, did you doing anything with volume variation?
 
I ask because my approach isn't a duration approach but rather a ramp up approach.  The goal of burn in is to loosen up new parts and get them largely to a state they will be during long term use.  To do this, you have to push the hardware (safely).  You can listen to a driver quietly for 100 hours and not do much with it.  You can spend an hour and continually ramp up the volume (under straining) and get most of the break in done very, very quickly.  There are general approaches, and there are efficient approaches.  Break in is not a myth.  It's a natural break down of new materials to a broken in state.  However, you can approach the process many ways.  I've gotten a number of earphones that have been used by other members for a good number of hours that were never fully broken in.  Expecting it to happen fully naturally or through certain approaches isn't exactly a great approach.  You really do need to put the earphone through its paces (safely within its actual capabilities, i.e. listening for harshness, strain, tonal change and staying below that level).  In many cases, it's useful to have a powerful amp to aid the process and fully operate the earphone.  For example, I got a pair of IE8 earphones with 30 hours on it that was never fully broken in by the previous owner.  I have a decently powerful amp, and it takes a lot of that power to actually bring the IE8 which is a pretty output capable earphone to its limits.  During break in it had several limit points as it loosened up.  I would scale up the output till I could distinguish stressing and then backed down slightly.  I let it sit for an hour playing.  I put them on again and reset the volume, ramping it up more until the new stress point.  I did this I think 4 times before I hit a static point that didn't change after repeat checks.  To show the level of scale, I had the volume around half to start before showing strain.  This was after around 30 hours of use by the previous owner and maybe 10 hours of use by me before deciding I really needed to finish breaking them in.  I ended up at a hair under 4/5 by the time I was done fully breaking in the earphone.  After maybe about 40 hours of mixed listening, it was only partially done.  It took me half a day to casually finish up the process.  Because of this and past experience with car/home drivers, I really dislike the duration type break in with the idea that time alone does it.  I'm a big fan of a ramp up process, of course done safely, although some people have a poor perception or awareness of stress/strain/harshness/tonal change cues indicating the mechanical limits of the driver.  I feel the ramp up process is quite fast with little need for such long burn in times.  There is some discussion about the effect on frequency response and end sound due to burn in process.  There is some discussion about the idea that you will end up with a different sounding product if you burn it in through a different method.  I have no intention to touch that concept because there is such a challenge to prove.  It ignores natural inconsistency in the products and assumes the micro variations will outweigh other macro factors of the driver, electronic, and earphone design.

 

[ericp10]

Thanks for this post @ dweaver.. Very interesting!!

 

[Anaxilus]

Quote:

You can spend an hour and continually ramp up the volume (under straining) and get most of the break in done very, very quickly. 

 
Personally I don't prefer the quick method.  I tried it once and wasn't satisfied.  I ended up redoing the burn-in.  I think time is a very important component and you can't fast forward thru it.  Just my opinion.