If your measurements are raw and uncompensated, why do the measurements show a relatively flat line? Raw measurements should have the general shape of the head-related transfer function, which isn't flat like a typical stereo microphone placed in a free space with flat-tuned speakers being played.

Excellent, detailed review with extremely useful comparisons. One of the best write-ups I have read on this site.

Such a detailed review. great read and I can't wait to get mine the next time it drops!

@miceblue, Good question. I was expecting a different result as well during my initial trials as well, but I was unable to get a curve reflective of the HRT function during my first three trials noise sweep tests. I used a Panasonic WM61-A microphone in my measurement set-up. The WM61-A does actually measure very flat until the upper treble range when calibrated. Its unequalized response will be flat within +/- 1.5 dB to 20 kHz. From my understanding, the majority of people who use this specific measurement set-up do not use compensation curves and their resulting measurements are quite linear. I have updated the review to address your concerns. I generated a new FR curve using the impulse response for a raw measurement reflective of the HRT function and I think may be closer to what you are looking for. Please let me know if you have any advice or suggestions with measurements! Thank you.
 
@ayaflo, @mkshm, @maheeinfy, @Colgin, and @Daeder - Thank you all for your kind words!! I like to write reviews for the benefit of the head-fi community. Hope do hope you all found the information useful and enjoyable to read. Feel free to post or PM me any questions you have.

I've updated some information in the review & added a few more measurements to the review. cheers!

Very nicely written bro, I might get this as a gift to my brother.

Great review!  Thank you for the time and effort you have put into this.  I just need to mention that for your classical/orchestral music suggestions, you only give the title of the work but no indication of which actual recorded version or performers you used, which can be quite misleading as, for instance, there are literally hundreds of recorded versions of Flight of the Bumblebee and Pachelbel's Kanon in D. Thanks!

@SyntheticShotz, @hakushondaimao, @bluemonkeyflyer, thank you for kudos on my review and the extremely kind words. Very much appreciated and made my day!
 
@DreamKing, thank you! these do make a really good present, I may actually also pass on my K7xx onto my brother if he ever gets more interested in more high quality gear. currently, he is content with his bose headphones, but with my gentle nudging things may change heh.
 
@ashutoshp, I agree, I personally feel some of the published reviews on a bit lacking in the information that I would like to know, so I try to include everything I personally would like to see in a review when I post. thank you for the advice. I made a small quick post on that website to see if I can get some feedback from the more experienced members of the measuring community. I am still learning on how to interpret csd plots accurately, so cannot yet comment on that particular measurement. My measurements were gathered using a Steinberg UR22 USB Interface w/ Yamaha ASIO + the Oppo HA-2 (amp) for the K7xx (I will update my review to include my measurement chain). From an ear test, the HA-2 does seem sufficient for the K7xx and it does appear to provide enough power from its specs, but it is one of the lower powered amplifiers I own.
 
@amigomatt, that is a extremely thoughtful suggestion and you bring up really good points! I don't have access to my entire classical collection (a lot of it is ripped FLAC with poor tagging, but I will make an attempt to update the test track information to include the actual performers over the weekend when I have more free time)

Thanks for your nice review! I just ordered one of the last 200 sets on Massdrop. Wish my Bravo Ocean can amp it well.

If the K7XX is the only item in your book to get 5/5 so far, perhaps you could look at the Shozy Alien. You may find that more "giant-killing" than this, although I do hold these in very high regard.

@avitron142, thank you for your recommendation. I will look into it, but I do personally strongly prefer external dac/amps over dacs. cheers!

@LS302, glad to hear you were able to snipe of few of the remaining pairs! look forward to seeing your impressions on how the bravo ocean pairs with the K7xx. I haven't had the pleasure to try the ocean yet.

Second production run of the AKG K7xx has started on the morning of 5/25/15 on Massdrop!! check it out here: https://www.massdrop.com/buy/akg-k7xx-massdrop-first-edition-headphones

Awesome and beautifully written. Detailed review! Keep it up, buddy  

how EXACTLY is this headphone any different  than the K702 65th Anniversary Edition? it says "configured by massdrop"  is this can just a  rebadge of the K702 65th Anniversary Edition? perhaps i missed something but I could not find one thing that massdrop says the configured any differently sound signature wise.

@MaN227, you bring up a good question. There is no official information that I could find answering that and I did not get a clear answer from Massdrop when I contacted them inquiring about that aspect. There are many users who own both who state they are sonically identical. There are some other users who state there are slight differences. It is hard to say without an official confirmation from AKG or Massdrop. Sorry I couldn't be more helpful

Absolutely amazing review sir, well done.

Thanks for this amazing review @money4me247 !  Pleasure to read I am using the K7XX with the new AudioMinor brand Pure Silver Solid custom cable for about 1 week and couldn't take the headphone out of my head. Unbelievable price/performance ratio!

@Baycode (and @TheVortex), thank you so much for your kind words! The value of the K7xx is extremely high and I personally have not found anything else with such a competitive performancerice ratio at release price.
 
I think discounted HD600/HD650 that hit near the $200ish price point and the few sales on the Philips X2 are other solid values and very competitive more neutral-orientated headphones for the mid-tier price bracket. I also really thought the HE-400 at the deal price of $300 prior to being discontinued to be quite competitive as well & they can often be found on sale for much less, but they do have a bit more unique sound signature, so more personal preference orientated. Beyers (particularly the DT880) have been hitting some low deal prices recently as well.

great review, I might buy a pair for my mom to use, especially for the great price of $200.