[grokit]

 
Quote:

it can be the dried out ear pads recovering

Good point.
 
 
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the increased weight explains the base response changing too you know

 

 

 

[keanex]

After finally having a pair that benefitted, heavily, from burn-in, I can say I know it's real now.

 

[Happy Camper]

Tyll and I are going to do some double blind testing to see if we can identify which 701 is "burned it" and which is not.  I am also going to suggest we try to make one headphone look like the other sonically by moving the ear cups around the dummy head, adjusting clamping tension, etc.  If we can make one graph look like the other this would suggest that we did not measure burn in.  If no matter what we do we cannot replicate the result other than using the burned in headphone, then this would suggest the possibility we measured the process.

At a past meet, we had a pretty new pair of 702 and a 701 that was several years old. Using the same rig, we could hear a difference between the two. We then swapped the pads and the differences reversed. The difference wasn't the drivers but the pads.

 

[rohan575]

exactly, the drivers as from my past experiments do not change in characteristics. None, of the electrical properties apart from weakening of the magnetic field strength (which takes a LOT of time to be significant) everything remains same. Especially when modern drivers are sealed  with corrosion resistant coils there is probably no electrical property (in my knowledge) which actually changes with time. 
 
The pads on the other hands do change,
 
Grokit:
 
the increased density of the pads (from moisture) actually do affect the lower end of the spectrum (longer wavelengths) more than they do for the higher end. 
 
 
Until and unless we have the technology to actually map quantitatively rather than qualitatively burn-in will remain an unsolved myth. 
 
 
 

 

[grokit]

Quote:

exactly, the drivers as from my past experiments do not change in characteristics. None, of the electrical properties apart from weakening of the magnetic field strength (which takes a LOT of time to be significant) everything remains same. Especially when modern drivers are sealed  with corrosion resistant coils there is probably no electrical property (in my knowledge) which actually changes with time. 
 
The pads on the other hands do change,
 
Grokit:
 
the increased density of the pads (from moisture) actually do affect the lower end of the spectrum (longer wavelengths) more than they do for the higher end. 
 
 
Until and unless we have the technology to actually map quantitatively rather than qualitatively burn-in will remain an unsolved myth. 

Gotcha, thanks. Perhaps this is due to less absorption and more reflection.
 

 

[Happy Camper]

Gotcha, thanks. Perhaps this is due to less absorption and more reflection.
 

Case in point is the tape mod on Grados. I also noticed an increase in bass impact and soundstage when I washed and dried my 701 pads with some weight on them. It made the cushion denser and put the driver closer to the ear.

 

[analogsurviver]

Burn in effects are real. Small in magnitude, but real. After all, everything is mechanical - even semiconductor materia(s) undego tiny deformations due to voltage/current forces acting on them .
 
I can confirm burn in in capacitors used in audio equipment. It varies in magnitude and time required to undergo changes to ceretain level, but it is real. 
If I do a recap on any given piece of audio equipment I am familiar with and confident enough to listen to it inserted in my sistem without first checking it on test bench ( DON'T do that unless you know perfectly what are you doing) there is some crackling for about five to ten seconds that dissapears after said few seconds. That might be initial burn in that will allow the equipment to function and measure as per spec. Such a piece of audio equipment will not sound good yet, it takes diffderent amount of operation for various type of capacitors with music to settle down to final SQ. I call that secondary burn in - and that can take up to 300+ hours to complete. It is not a placebo - i tried it with the same "box" that looks externally exactly the same, has exactly the same components built in, yet one was burnt in and another with maybe couple ( under 10 ) hours of operation. People consistently differentiated between the two. 
 
I do not therefore ever release any component to the end user that has not been subjected to at least 100 hours of operation - saving me from the chore of answering phone/mails regarding changes in first hours of operation. Customers "get it" after that in a natural way; I certainly agree there is also psyhological aspect to the burn in issue, with people getting used to any piece of gear and listening through it - but that comes into play towards the end of the burn in period where changes get ever smaller. That "initial" burn in is real an verifiable either by listening ( in headphones of course) or hooking up your gear to some scope/analizer - BUT you have to have everything up and going before switching device under test on - it really lasts for about 10 seconds at most. 
 
Burning in of loudspeakers and headphones is another matter. It is true if you do not like the headphone/speaker initially, burn in is not likely to change it enough for you to fall in love with it. But if it is close to your liking - give it a good and well controlled burn in. Suspension in drivers is likely to loosen up when subjected to relatively large amplitudes of low frequencies - yielding looser suspension that should result in lowering of the resonant frequency for that driver. Preferably well below audible range, below 16 Hz.
 
http://en.wikipedia.org/wiki/Resonance
 
Any resonance is audible due to phase shifts it creates, even if it is of relatively low amplitude. High Q resonances of as little as 0.2 dB in midband where our hearing is most sensitive have been reported to be objectionable in the long run.
 
Resonance(s) in bass colour the sound well into the midrange ( via mentioned phase shift(s) ) and whatever it can be done to eliminate resonance or at least push it towards the lower frequency is a step in the right direction. Please note that analizers to be used should cover bandwidth greater than the officially generally accepted hearing range for humans, from 16 to 20000 Hz, in case of bass resonance preferably going to at least 5 Hz if not DC for the results to be meaningful and accurate. It is easy to hear the (d)effects of resonance pleagued reproduction once you hear it right. Particularly the correct representation of acoustics of the venue preserved in well done recordings will markedly improve - even when it means pushing low frequency resonance of headphone/speaker from say 25 to 16 Hz. If resonance frequency is higher up than say 25 Hz, as in majority of cases, effects are more pronounced and colour further into midrange.

 

[ExCelciuS]

Burn-in is real, my K702 sound much better after 1000+ hours of normal usage, I use my K702 normaly for average 5 hours a day, and it's been 9 month now, the sounds open up, tonality, bass, and everything else is just better. 

 

[sonitus mirus]

How come a pair of headphones never seems to get worse over time?  You rarely see anyone comment about how much they loved their headphones when they fist got them, but then they slowly got worse over time.    

 

 

[castleofargh]

  Burn-in is real, my K702 sound much better after 1000+ hours of normal usage, I use my K702 normaly for average 5 hours a day, and it's been 9 month now, the sounds open up, tonality, bass, and everything else is just better. 

on the other hand, with 5hours a day for 9 month that's more than enough to be brainwashed into loving even justin bieber.
even if a headphone changes, be sure that our mind adapts to it a all lot more.

 

[Toom]

If I was a headphone manufacturer and wanted less people to return my phones because they didn't like the sound, I might support the concept that at some magical point - which just so happens to be past the returns policy - the headphones will be sufficiently 'burned in' that they sound their best.

Or maybe I am just cynical.

By the way, as much as I dislike her music, what's with all the abuse for Pink? Plenty of other artists making noise out there....

 

[OddE]

  Burn-in is real, my K702 sound much better after 1000+ hours of normal usage, I use my K702 normaly for average 5 hours a day, and it's been 9 month now, the sounds open up, tonality, bass, and everything else is just better. 

 
-You know, the fun experiment to do for the semi-well heeled among us would be to buy two pairs of K702s, start using one while leaving the other in the box. Then, once you feel that the phones have really burned in properly and improved, open the box and put on the fresh pair and compare them.
 
Better still, have somebody blindfold you and put one or the other on, then try to identify which is which. (It might be a good idea to swap pads between them, too - I'd imagine after hundreds of hours of use, the worn set would feel different from the brand spanking new ones.

 

[zareliman]

I tend to think that "burning-in" has a negative effect on earphones. Theres a local store around here where you can test their headphones and IEMs. I assume those test units are way more burnt than my personal IEMs (because I don't purposely burn them by leaving them playing overnight or something), but when listening to my Deltas versus the test ones, mine sounded way better IMO. The test ones were like distorted and sounded even like a clipped record to some extent. Now, the differences are subtle but you can hear them. If anything I believe that earphones are meant to sound the best when they're mint new, because it is in the company's best interest to give you the product properly "broken in" when you buy it (at least in this case).

 

[ThomasHK]

My 2 cents on the topic (professional headphones engineer)
 

• There is no point in comparing two of the same headphones as a test of identifying the effect of break in. There will always be differences between mass produced samples. Tolerances for anything but the highest priced headphones will be at least +/- 2dB across the entire frequency range. Of course you will be able to hear those differences and inter sample variation is much larger than what break in could possibly bring.
   
• I've yet to see any scientific proof of drivers with PET/PEEK/PU showing any sign of break-in. They don't have surrounds or spiders like regular loudspeaker drivers, which do get effected by use over time (e.g. rubber gets more compliant).
   
• What does change ... cushions. Leather (real or fake) gets softer and memory foam has changing properties as function of temperature. Both of those can lead to an increase in bass due to a tighter skin fit with less leakage and less "cushion bounce" leads to tighter bass. We don't really have a very scientific name for cushion bounce, but it can often show up in the low to low mid frequency range as a wiggle in the frequency response. It's essentially a whole headphone resonance (think mass on a spring). As the stiffness of the cushion changes, so does the "cushion bounce". 

 

[Arunabha Lahiri]

My 2 cents on the topic (professional headphones engineer)

1. There is no point in comparing two of the same headphones as a test of identifying the effect of break in. There will always be differences between mass produced samples. Tolerances for anything but the highest priced headphones will be at least +/- 2dB across the entire frequency range. Of course you will be able to hear those differences and inter sample variation is much larger than what break in could possibly bring.
   
    
2. I've yet to see any scientific proof of drivers with PET/PEEK/PU showing any sign of break-in. They don't have surrounds or spiders like regular loudspeaker drivers, which do get effected by use over time (e.g. rubber gets more compliant).
   
    
3. What does change ... cushions. Leather (real or fake) gets softer and memory foam has changing properties as function of temperature. Both of those can lead to an increase in bass due to a tighter skin fit with less leakage and less "cushion bounce" leads to tighter bass. We don't really have a very scientific name for cushion bounce, but it can often show up in the low to low mid frequency range as a wiggle in the frequency response. It's essentially a whole headphone resonance (think mass on a spring). As the stiffness of the cushion changes, so does the "cushion bounce". 

Thank you for sharing. I too believe the same though I am no professional..