Exactly my thoughts. I own and use HD600 - for rock and metal, meaty punchy dance, pop etc. HD650 - occasionally HD800 - jazz, classic, instrumental etc. So I will describe my ideal headphone comparing to them. I imagine HD9xx(?) series like this: Type: circumaural, open-back. if there...

Not sure whether it was discussed or not. Sennheiser has silently removed HD700 from their site. https://en-us.sennheiser.com/audiophile-range

My pair of HD800 has higher frequencies somewhat cranked up and 3 kHz is somewhat recessed as well

The test is finished.  These are the results http://www.hydrogenaud.io/forums/index.php?s=&showtopic=106354&view=findpost&p=874674  

Since You don't cooperate and don't even answer a simple question.   All right. Nevermind. Have a nice day. 

I mean,  have You submited some results for this test?

  All right, it's possible to test high bitrates. Though we need a good amount of samples for this test to justify move to higher rate.     Have You submit some samples?

BTW, there is an open public listening test    MP3, AAC/MP4, Ogg Vorbis, Opus.   http://www.head-fi.org/t/728636/public-listening-test-of-codecs-mp3-aac-mp4-ogg-vorbis-and-opus Everybody is welcome to participate    

Yes,  128 kbps and higher will be more interesting.  But high bitrate are hard to test. People inform that it's already hard to listen difference between a high quality MP3-128 kbps and a lossless.    People can claim that 128 kbps is low and not enough for a good quality  because they can...

Codecs AAC(MP4), OGG Vorbis, Opus@ 96 kbps are compared to classic MP3@128 kbps. Which is better? AAC? MP3? Opus? OGG Vorbis? The following codecs will be tested: AAC iTunes 11.2.2 Opus 1.1 Ogg Vorbis aoTuV Beta6.03 MP3 LAME 3.99.5 AAC FAAC v1.28 (Mid-Low Anchor) AAC FAAC v1.28 (Low...

  Backwards?

Quote:   Really?     All of them 0204, 0202 and 0404 have the very same AD  converter  AK5835(A). 

I've just realized that 4 last numbers of my HD800's serial number  is my birth date (month and day).  

Thank You for fast answers.    Actually it makes sense as this source says there are 5000 of pairs per year http://www.whathifi.com/blog/sennheiser-hd800-hands-on-preview-plus-how-the-163-1000-headphones-are-built 5000 per year, so in 3+ years there are ~16000

I wonder which the latest serial number is.   I've got a new pair last week and S/N is 131xx.    That means there are ~14000 of these pairs  and  ~4500 were produced annualy since 2009.