[floydfan33]

 
Here's mine.

 

[daltonljj]

Just got mine yesterday.

 
Noticed the typical 6k peak isn't as significant here.

 

[Mike F]

 
 
Here's mine.

 
 

  Just got mine yesterday.

 
Noticed the typical 6k peak isn't as significant here.

Well, of course, anybody would prefer the one which looks flatter, but I do seriously question whether there would be a real audible difference between them, i.e. a difference that one could reliably detect in a blind listening test. Your eyes say that there would be a noticeable difference but I very much doubt that would be audible.

 

[daltonljj]

Generally IMHO i feel that it sounds almost the same in overall aspect. However it does sound a little less harsh. I've been eyeing on the HD800 for a really long time (2years) constantly heading down to many headphones shops to listen to it. When I finally got it i noticed the treble in mine seems a little less harsh which was why i decided to request for the frequency response. 

 

[Xennon]

As a long-run HD800 user (3 years), I feel that frequency charts depict more or less an accurate picture of the relative weight of each frequency range. Within three years I auditioned a handful of HD800s, the in-between HD800s (16XXX) I own was definitely not as edgy on the upper midrange as some other HD800s. Its frequency response somehow explains this difference:
 

 

[hpfalcon]

 
Here's mine. Haven't heard other HD800s to compare to so a little hard to discern the 6k peak for me. Id guess its probably audible but even more subtle than cable upgrades

. But would love to compare with a pair without the peak sometime

 

[peanuthead]

Me and a buddy recently compared 2 HD800's, one with a frequency chart showing a huge bump at 6,000Hz (his) and the other one showing a relatively flat bump at 6,000Hz (mine) and put them through a sibilance torture test.  Result:  we could not discern any difference between the two.

 

[akhyar]

Me and a buddy recently compared 2 HD800's, one with a frequency chart showing a huge bump at 6,000Hz (his) and the other one showing a relatively flat bump at 6,000Hz (mine) and put them through a sibilance torture test.  Result:  we could not discern any difference between the two.

Good to know.
Mine has a bump at 6kHz region, but I don't feel the need to sell and buy another one with no peak at 6kHz

 

[Mike F]

I'd be really VERY surprised if there was any noticeable difference between different HD800's - at least none that can be reliably identified in a blind test. I bet it's very easy to be convinced that you really CAN hear a difference between different pairs whilst looking at the graphs, but reliably in a blind test - I highly doubt it.
 
It seems inconceivable to me that there would be clearly audible differences between different pairs of one of the best and most carefully made headphones in the world (not to mention Sennheisers flagship model), and that Sennheiser would then provide a graph to prove how different they sounded! No, surely the graph is provided to show how very consistent they are. It's just a nicety to have an exact measurement of each individual pair.

 

[Xennon]

I would like to make a clarification upon these well-put comments. Including me, perhaps no one here thinks of selling their HD800s only based on this data. Any such difference would be indeed too subtle, if not inexistent -- I still acknowledge the possibility of the latter. Therefore it is untenable to argue that these very minor differences do dramatically change the sound signature or the overall characteristic of the HD800s. However, it is not less noteworthy that what is frequently called 'harshness' on the upper-mids is also something subtle for the HD800s -- it does not always surface, it is not always felt in any HD800s. The common wisdom is rightly to have faith in Sennheiser about the overall standard quality, but it is also understandable for the same reason that each graph is carefully made by Sennheiser to be indicative of some little nuances. Most of our graphs have very similar curves between 20hz-1kHz (almost exactly the same if you check them carefully), and then they somehow begin to fluctuate after it. Both the consistencies and changes suggest that the measurements are carefully made, and some nuances are caught only at certain points. This is of course purely technical up to here. A useful method to seek these nuances by ear is to focus on 6kHzs relative position to the other frequency ranges within each HD800s. For instance, I was not surprised at all when I saw a 4kHz prominence on my HD800s instead of a 6kHz peak, because I never feel a 6kHz peak on the midrange, but instead a nebulous 3-4 kHz echo. With regard to any possible subtleties, what one feels after long sessions of listening matter a lot. This is why I think long-periods of carefree listening are not less helpful than extremely conscious blind tests. 

 

[Mike F]

  I would like to make a clarification upon these well-put comments. Including me, perhaps no one here thinks of selling their HD800s only based on this data. Any such difference would be indeed too subtle, if not inexistent -- I still acknowledge the possibility of the latter. Therefore it is untenable to argue that these very minor differences do dramatically change the sound signature or the overall characteristic of the HD800s. However, it is not less noteworthy that what is frequently called 'harshness' on the upper-mids is also something subtle for the HD800s -- it does not always surface, it is not always felt in any HD800s. The common wisdom is rightly to have faith in Sennheiser about the overall standard quality, but it is also understandable for the same reason that each graph is carefully made by Sennheiser to be indicative of some little nuances. Most of our graphs have very similar curves between 20hz-1kHz (almost exactly the same if you check them carefully), and then they somehow begin to fluctuate after it. Both the consistencies and changes suggest that the measurements are carefully made, and some nuances are caught only at certain points. This is of course purely technical up to here. A useful method to seek these nuances by ear is to focus on 6kHzs relative position to the other frequency ranges within each HD800s. For instance, I was not surprised at all when I saw a 4kHz prominence on my HD800s instead of a 6kHz peak, because I never feel a 6kHz peak on the midrange, but instead a nebulous 3-4 kHz echo. With regard to any possible subtleties, what one feels after long sessions of listening matter a lot. This is why I think long-periods of carefree listening are not less helpful than extremely conscious blind tests. 

 
I totally agree with the highlighted part of your post. I've often found the same to be true. Contrary to popular belief, I think that we DO have good aural memories (or at least some of us do!), and would agree with you that impressions gained from longer listening sessions are often more reliable than trying to establish subtle differences with quick A-B testing.

 

[ardilla]

I have currently two HD800's in my posession. One is serial 16XXX, the other is 28XXX serial. They sound pretty different for identical headphones. The 28XXX is a bit fatter, bolder, bassier, mids more up front - while it is loosing some of that exceptional soundstage wideness in comparison to the 16XXX. The 28XXX sounds louder too when comparing them side by side I have to adjust the volume to feel they are leveled. Both are good, and actually - if you are a headphone freak, there is no doubt that you can justify owning them both - even though they still sound like HD800. There is more variation between these two pairs than what I get with different amplifiers. I can not claim that all 16XXX and 28XXX will sound like mine - but if this is just within standard tolerance, I'd be really surprised. My guess is that Sennheiser adjusted the damping in the driver unit just a tad, to get a less clinical sound. Which is what users have been asking them to do - basically.  
 
Interestingly - the FR-charts are almost totally in sync - I did an overlay: 
 

 

[wink]

It could be that one set has worn earpads causing the 'phone to sit closer to your ears, making it louder and more fuller in sound.

 

[ardilla]

  It could be that one set has worn earpads causing the 'phone to sit closer to your ears, making it louder and more fuller in sound.

 
Nah - I have tried pressuring and lifting the cups while music is playing, but the difference is still there. Pads feel and look similar. I might try swapping them just to be 100% sure. 

 

[Mortalcoil]

  I have currently two HD800's in my posession. One is serial 16XXX, the other is 28XXX serial. They sound pretty different for identical headphones. The 28XXX is a bit fatter, bolder, bassier, mids more up front - while it is loosing some of that exceptional soundstage wideness in comparison to the 16XXX. The 28XXX sounds louder too when comparing them side by side I have to adjust the volume to feel they are leveled. Both are good, and actually - if you are a headphone freak, there is no doubt that you can justify owning them both - even though they still sound like HD800. There is more variation between these two pairs than what I get with different amplifiers. I can not claim that all 16XXX and 28XXX will sound like mine - but if this is just within standard tolerance, I'd be really surprised. My guess is that Sennheiser adjusted the damping in the driver unit just a tad, to get a less clinical sound. Which is what users have been asking them to do - basically.  
 
 
 
 

 
I agree with what your ears are telling you 100%.
 
From my own experiences based on owning 2 sets of HD-800 (returned one, own only the one now) there is indeed a difference between units.
 
Some of these differences may not be audible due to the fact that the variance may be so minimal.  In my case however the freq chart showed the difference in the 6khz are...it was noticeable.  Both units were purchased at the same time and both were new.
 
I posted my findings somewhere in this thread along with both freq charts for comparison.
 
There will be some though who will claim that there is no difference.  http://www.head-fi.org/t/433059/sennheiser-hd800-certificate-for-frequency-response-arrived/480#post_10424772