Is burn in real or placebo?

Discussion in 'Sound Science' started by hifi man, May 13, 2013.
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  1. amirm
    Why? The small cavity of your ears will change substantially in volume, resonances and reflections if the thick cushions compress more.

    Here is a quick test I just ran on my headphone measurement system. I kept my finger in the same place on the headphone, measured, and then pushed it in some and measured again:

    headphone test with and without finger pressure on pad.png

    We see that the volume clearly changes and the response overall changes in some places.

    Really, if we are going to consider "burn-in" of the driver, surely there are more changes to the cushion than that element!
     
  2. Danamr
    While I agree with what you are seeing, I know that my HD800 phones do not end up at the exact same place on my head every time, and the difference can be as much as a full cm. What happens to your traces when you start moving the phones laterally?
     
  3. amirm
    Oh they go nutz. Headphone measurements are exceedingly variable and can be quite unreliable or at least unrepeatable. When I did the testing above, just the mere fact of putting my finger on the back of the headphone caused significant difference in response! This is why I kept it there as reference without pressure as opposed to testing the headphone without my finger there.
     
  4. Brooko Contributor
    For IEMs, depth and angle of insertion will cause a magnitude more difference in frequency response than any supposed change from burn in. For headphones - pad compression or position on head will do the same. Difference in volume for both will again cause a magnitude more perceived difference. And our reliable auditory memory is fleeting - a matter of seconds. So why is it that anecdotal evidence of perceived change is taken as fact and pushed as evidence of burn in when we know it can’t possibly be the cause without discounting other factors.

    And why is it that when we actually measure - the differences which could be possibly attributed to burn-in are of such a magnitude that they would be inaudible anyway :wink:
     
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  5. HotIce
    It is not only the volume, but also the position of the mic compared to the driver, which changes with pressure.
    There were sweeps posted in a link I am not able to find anymore, were using the dummy head, and varying the position of the mic within the ear cavity, changed responses pretty dramatically.
    Curious, which test harness did you use for the graph you posted?
     
  6. HotIce
    In lack of answer, these videos are interesting in the subject:



     
  7. HenkdeFries
    That's pretty interesting to see, in that it unexcitingly drops evenly across the board. Do you reckon different fabrics are prone to more heavy changes
     
  8. castleofargh Contributor
    with pressure on the pads, the driver comes closer to the mic/ear. so louder is the first expected change. the rest is a matter of how the all acoustic chamber is changed(in volume, but also possibly a little in shape), how the pinna reflects sound from the new driver position, and TBH maybe how we get used to a different position on the head once the pad are a little worn out(which shouldn't be visible on that measurement).
     
  9. amirm
    It might. If they happen over time though we likely adapt and it won't be an audible thing.
     
  10. krismusic Contributor
    It's it necessary to spend that kind of money on transport only for Mojo? How about the Pioneer 300r or a decent phone?
     
  11. Dawnrazor
    I experienced night and day differences with my M1060 mkiis. Out of the box they were good and the bass was amazing. Few hours later they were unlistenable as the highs were just wrong. Too much, much too much.

    So on went the burn in tones while I slept. Listened in the morning- aweful. Back went the tones and this cycle repeated until about 70-75 hours of burn in tones it sounded great with all the highend glare and unpleasantness gone. Over 120 hours now and its a different headphone. I can listen to alot more recordings without fatigue and everything is more enjoyable. Though the bass isnt quite as good. It seems to be a bit less in level or punch but still great.

    Maybe its a planar thing but IMHO lots of the M1060 high issues were most likely just people not burning them in long enough.

    My M565 didnt seem to suffer any of this and just sounded great from the get go.
     
  12. Redcarmoose
    It’s so true that there is really no way to accurately remember an exact tone or sound signature. Vision too is highly unreliable as there are figures which show we may only mentally see 10% of the information coming into our brain from our eyes.

    Expectations color our perception of almost everything. Still there are lasting and absolutely critical ideas a person can perceive. I’m a guitar player and guitars are a very subjective musical device.

    When putting a live show together many times a band will choose guitars and amplifiers specifically so each person has a place in the mix, kind of like a guitar player choosing only to use his treble pick-up so that the rhythm guitar and lead guitar parts will each have an area of definitive space in the mix.

    Though let’s just say a guitar player walks into a music store and picks an acoustic guitar simply to play by themselves. If it’s an experienced player they have tone parameters which are set in their memory.

    And of course with out measuring............. these tone ideas are very much influenced by the brand/style and wood used to make the guitar.

    In acoustic guitars you have styles of bodies which are replicated over and over again using similarly comparable woods to get a comparable sound.

    The art of making guitars is obviously very complicated and convoluted, but let’s generalize and say a large white maple guitar may have a bright and loud sound when played. Also a smaller mahogany guitar is going to be both darker and quieter when comparable to the maple guitar. Guitar makers are always taking this wood sound knowledge and making various changes with every new model.

    Now in this instance the player is also the listener, where in audio we just have people listening to their stereos. And in further regard the player is doing multiple things while playing and listening to how the instrument reacts. There are values of brightness, sustain, harmonic richness, levels of extension into the treble and bass areas, and......just like headphones some guitars can be more mid-centric................


    But my point is that even though guitars can change slightly due to atmosphere, a guitar player knows his instrument. He knows the sound that’s taking place, he remembers the character. This tone is what musicians will listen for before they go out onstage to make sure there are no issues. Many times something in the personality of the guitar is off and it takes a while to pin down what it is. There are issues which are way more drastic like if the guitar is not in-tune with itself. But over all these things are almost like living creatures having personality and character which is unique unto themselves, never wavering much, year in and year out.

    The argument could be that burn-in changes are way more understated than the tone of different guitars. My argument here is that some people can get a pretty good idea about a musical device. These characteristics can be really small, and of course be different day to day in perception, but they can exist in what some people hear.
     
    Last edited: Feb 4, 2018
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