AKG K712 Pro

Build: Solid.
Comfort: Excellent. Very light. Leather strap can pull hair, though.
Isolation: Open.

Bass: Roll off under 50Hz. Bloated midbass. 1.25/3
Midrange: Lower mids emphasis with upper mids fall decreases clarity of the mids. 1.5/3
Treble: 6k peak gives sharpness to the sound. 1.25/3
Tonality: Above average. 2.50/5
EQ: Needed. For my preferences, mandatory. Try Serious SBAF or Optimum HiFi +4dB.

Detail: Good. 2/3
Imaging: Fantastic soundstage, probably second only to HD800. 2.5/3
Dynamics: Below average. 1/3
Tech: MidFi soundstage king. 3.25/5

Bias: 3/3
Interestingly, this is probably my most used headphone. Why? 1) Comfort. Light, open and breathable. 2) Soundstage. Loving the openness of the sound, it is high on my enjoyment list. 3) It is clear and detailed headphone when EQd. With EQ fixing tonality issues, it really shines.

Score: 2.5/5

Value: Worth the price. In Europe you can now get it for about 200 EUR, which is great price for what it offers. In my local shops, price is more like 350 EUR, which is a different proposition. Of course, you have to value soundstage and comfort and be prepared to use EQ.

The AKG 712 Pro engineers decided to  create a  newly designed headphone rebut to all the critics of the AKG sound which they say tends towards  treble extension at the expense of the rest of the sound.
The problem is, the engineers forgot to put the treble back into the new design after they warmed up the overall tone with more low mids and bass extension..
The AKG 712 Pro box says......'"Now with 3db more bass", and after listening to these for a few days, ive concluded that perhaps 2 db would have been the answer, as these headphone are just too soft/dull/relaxed sounding.
Im not certain if the treble and mids are just too dialed back by design,  or if they are just being covered up by that "3 db" of "added bass".
Whichever, or whatever, these phones have no zing or sparkle in the treble and the mids need an air pump.

 
The AKG K-712 drivers are not the same as the previous K-Series headphones. I feel better having said that. Fhew. I don’t want to bore you with more specification information in the beginning of this review, so I will start off with the Conclusion first. You can read the details afterward. That is just how I roll…#likeaboss

 

The End Credits

AKG has created a mini masterpiece in my opinion. I enjoy this headphone a great deal and it will become my go to reference headphone for the time being. She is slick, sexy, well balanced and crazy comfortable. Top that off with an unpicky nature when it comes to amplification and you’ve got yourself a real winner. I consider this headphone one of the best multi-media headphones produced lately. I can’t believe I am saying this, but this AKG headphone can sound great with rock and moderately bassy tracks. If you are a fan of the Hifman HE-500 or HE-400 but are a bit troubled by their fatiguing sound and weight, grab yourself one of these K-712′s or at least attempt to demo one. You will not be disappointed. The K-712 is buttery smooth and soft on the low end with more quantity than the previous K-Series headphones in the past. AKG has done a great job and this headphone is a gorgeous testament to how well a headphone in the mid-tier price range can sound.

 

 

The Bass

I realize it is hard for people to accept the possibility that an AKG K-Series headphone can produce a solid low end. I know…crazy right? I was pleasantly surprised to hear the K-712 output very nice low end quantity with proper EQ functions in the mix. Certainly a few steps up in quantity over the K-701 or similar models. Don’t expect a Denon D-1100, D-5000 type low end or anything basshead worthy, but do expect a more than sufficient, well balanced and divinely executed low end. It seems the K-712 is a bit voracious when it comes to voltage despite its lowly 62ohm Impedance rating. I’ve noticed that with more power on a higher gain, the low end will reveal it’s true nature. Directly fed by my ALO International on High Gain, the experience is sufficient on the low end only with proper EQ of my portable source. Without it, the headphone sounds like a typical AKG headphone: lean on the low end and a bit thin overall. However, driven by my Burson Conductor SL the experience is exceedingly smooth and more than plentiful for me in sheer quantity so long as my source is capable of pushing solid low end. Broad and stark neutral, this headphone is a great contrast to something like the Audeze bass experience, which is much more focused and in your face, less broad sounding and much harder on the slam effect than the K-712′s softer tone.

 

 

The Mids

No one quality in this headphone stands out from the rest. V-shape is totally absent from this headphone, which to me is a great thing. I hate recessed midrange or either of the three major quality factors ( Bass, Mids, Highs ) appearing more prominent than the other two in a physical sense. This is a very linear experience throughout the spectrum, very flat and well balanced sounding. Exceptional for multimedia usage and gaming in general. Dare I even say this is one of the best gaming and media headphones I’ve heard in many years.

Vocals seem a bit loose and panicked in their upper most areas, nothing serious and for the price I consider them very well set up. Not too relaxed but also not truly forward. This is not a common trait for a headphone with a stereo image that tall and wide, typically this type of sound stage experience results in a more relaxed and pushed back vocal experience. Somehow, AKG avoided that and pushed the mids upward just enough to blend seamlessly with the Bass and Highs.


 
Tracks like Jamie Foxx’s – Why off his album titled Intuition result in an unexpected smooth and balanced sound signature that I was not at all ready for. Upon first listen, I expected this headphone to be a clone of the K-701 with some minor tweaks, but was pleasantly surprised when that midrange and low end seemed more powerful and tonally balanced together. Certainly not as aired out or separated as the previous models before it, however the K-712 seems to produce exceptionally smooth and buttery bass along with the majority of the midrange. My only gripe is that the upper most area of the midrange seem a bit nasal to my ears, producing a little too much bite and hiss on notoriously sibilant tracks you might have in your collection. If the track is sibilant, the K-712 will sound sibilant. It is not at all a forgiving headphone when it comes to the upper midrange and above.

 

The Highs

The major flaw of this headphone is certainly the upper region. I find it too unforgiving and too true to the track. It will sound sibilant and harsh if your track happens to sound that way, so do not expect a forgiving experience and soft natured upper regions on his headphone. Despite that, the highs are very responsive and require an excellent amplifier to properly tame. Properly tamed by my Burson Conductor SL using the 9018 chip, a Dac Chip that is one of the most beautifully dynamic and forgiving on the upper regions piece of equipment I’ve ever experienced, the entire K-712 journey on the upper region ends up inverting itself into a relaxed presentation. Summed up, use an amplifier known for stereo imaging qualities and very smooth, forgiving highs and you will be rewarded with a highly dynamic and tonally balanced experience throughout the entire audio spectrum.  Beautiful. So beautiful in fact, I stopped using my Sennheiser HD700 completely. I have no desire to use it now, as I enjoy the flavor and overall balanced sound signature of the K-712 even more.

 

 
Bonus: Can’t do better than the Burson Conductor SL in my opinion, the amplifier literally made my ears melt with its sheer awesomness and ability to mesh with anything I tossed at it. From the LCD-3 to the K-712, the Conductor SL made everything sound great. Everything.


 

 

Stereo Imaging

I can easily consider this K-712 a drastic improvement over the last generation of K-Series headphones, it really does seem more precise and more solid sounding than anything before it. With that, the stereo image separation takes a nose dive and turns into something more focused, more realistic and less splashy as the prior K-701 sounded. There is such a thing as having too large of a sound stage, as with that large stereo width comes the potential of the image sounding overly thin, stretched out and with a looming sense of ” something just isn’t right “. Thankfully, the K-712 fixed all of that and improved the sound stage quality in general, but lessened the overall width and separation by a fair degree. Expect a very nice stereo width with good separation qualities and good height, a solid low end combined with a solid midrange makes this headphone fairly well rounded. In fact, it might be the only well rounded AKG headphone I’ve ever heard.


The K-712 sounds a lot like the Sony MA900, which itself is a fantastic value, one that I consider better for movies and media in general due to being feather light and more noggin’ friendly with respect to it’s simple headband. Liked the MA900? You are going to love the K-712. Despite the MA900 not having the excellent pinpoint accuracy and less clarity all across the board vs the K-712, it still remains, in my opinion, the best all purpose headphone ever produced.

This headphone still sounds like a typical AKG set of cans with regard to the overall coloration and presentation flavor, which is somewhere between natural and studio monitor. Hard to say what the real sound type is here because the sound signature drastically changed when I swapped my Burson Conductor SL’s 9018 chip for the very warm 1793 chip, which itself is an upgraded dac chip similar to the one in the original Burson HA-160. Depending on the headphone, you’ll want to swap out. No question the 9018 is more clear, dynamic and solid, but the overall warmth and coloration of the K-712 almost took on an Audeze house flavor with that 1793 chip in the mix: Natural and a bit warm on the low end. Where as with the 9018 chip, the K-712 tended to sound more like the Hifiman headphones. Nice to see this K-712 responds marvelously well to different amplification sound signatures. At 64ohm impedance, the headphone is very easy to drive and functions very nicely off my iBasso DX50 even on low gain, but I suggest trying to acquire a better source with regard to bass output to do the K-712 justice on the low end.

For some reason, more power and driving force equates to a better bass experience. Taken from an already smooth and lean low even via just my DX50 and ALO Internation for example, to one of the smoothest low end experiences with plenty of quantity that I’ve heard in years with the Burson. The bass quality rivals the Hifiman HE-500, which in my opinion has one of the most pure low ends in it’s price tier. I think the K-712 with proper amplification and dacs can achieve stunning clarity on the low end and mid range. Again though, watch out for that upper region as it is very unforgiving. Thankfully, the Burson really tamed it and toned it way down.

 

Final Thoughts

No doubt about it, the K-712 is a real winner in my book. I’ve been using it a lot with online gaming and movies in general. Recently, a petition appeared in some online gaming communities to have me banned from playing on my favorite servers. I can hear the enemy from so far away and with such precision due to that wide stereo image, that I often get kicked out of the game by the server owners who think I am hacking. I admit, on some instant replays after I get my easy kills, it does seem like I had some type of foresight to know exactly where said enemy will be appearing behind, popping up out of or jumping over. As a gamer, I’ve never been happier. I consider the K-712 one of the best overall gaming headphones to date and have enjoyed every second of usage with it online. The headphone is very pinpoint accurate and due to it’s light weight design at around 240grams, it can be worn indefinitely and easily for hours if need be during your late night gaming sessions.


 
Bonus: Borderlands 2 is an Audiophiles playland in digital format. If you are an audio junky, do not miss this game. It has some of the most dynamic and professionally rigged audio in all of gaming history. Highly immersing, highly engaging and accurate. Bullets, explosions and character interactions are beautiful and recorded with extreme love, affection and detail and the entire Borderlands pilgrimage is nothing short of stunning with the K-712.

 

Keep an ear out for movies with poorly recorded upper regions, as bullets, explosions and screams are just too painful on the K-712 to begin to bare for me in some bluray and dvd movies. Without the Burson or a good receiver in the mix, I tread carefully when it comes to media usage in general. No fault of the K-712, it is certainly the fault of the films sound editor failing to do his job properly most of the time. Sometimes, the treble can get too hot, so be careful with those action movies or Shia LaBeouf incessant screaming scenes.

Despite the lightweight design, AKG still hasn’t learned that the giant halo design is undesirable. The K-550 has a beautifully designed and simplistic headband with a similar sized earcup design, so I see no reason for reverting right back to the Dark Ages of Audio when headbands were designed the way most AKG headphones are. The upper region is too unforgiving and unreflective of it’s price tag and require a dac or amplifier that can tame it. However, all other sonic qualities remain gorgeous. The K-712 is beautiful, boasting exceptional smoothness on the low end, a highly immersing stereo image and is something that will make online gamers very happy. AKG will be releasing the K-812 very soon and I am certainly willing to fight someone over a pit of acid and spikes just to be among the first to hear or review it.

8.5/10 Great Job, AKG!

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Technical Specifications

GENERAL

Headphone type open
Audio Frequency bandwidth 10 to 39800 Hz
Sensitivity headphones 105 dB SPL/V
Max. Input Power 200 mW
Rated Impedance 62 Ohms
Earpads
Detachable cable yes
Cable Length 3 m
Earpads Replaceable yes

AUDIO INTERFACE

Type Screw-on Jack Combo (1/4″ and 1/8″)
Gender Male
Contacts 3-pin
Interface Finish Gold
DIMENSIONS / WEIGHT
Length 113 mm
Width 199 mm
Height 212 mm
Net Weight 235 g

A big thanks to Headphone.com for loaning me the AKG K712 Pro and HD650 for this review.
 
A hearty thanks to Tyll Hertsens from Innerfidelity.com for loaning me a pair of AKG Q701 also used in this review.
 
Specs:
http://www.akg.com/K712+PRO-827.html?pid=1408&techspecs
 
Frequency Response Charts:
http://graphs.headphone.com/graphCompare.php?graphType=0&graphID[]=853&graphID[]=4163&scale=30
 
 
 
 
 
 
 
 
 
GEAR
Initial testing on an iPod touch ( 3rd Gen )
The idea with the iPod is to ensure that it can drive the headphone to loud listening levels and still remain under 100% volume.  The K712 Pro did that and sounded great through the iPod touch.
 
Full review conducted on my home rig:
Sources:  PC playing 256kbps AAC or better files, Internal DVD player, iPod Touch 3rd Gen.
DAC:  Grace Design m903 ( 24 bit mode )
AMP:  HeadRoom BUDA in single ended mode
Interconnects:  Kimber PBJ RCA and Seismic Audio Balanced patch cables
 
INITIAL TEST TRACKS
Check Corea:  Three Ghouls, Part 1
Karsh Kales:  Longing
Maroon 5: Won’t Go Home Without You
Michael Jacskon:  Wanna Be Startin’ Somethin’
Patricia Barber:  Dansons la Gigue
The Beach Boys:  Surfin’ USA
They Might Be Giants:  Spiraling Shape
 
FIRST IMPRESSIONS
A quick inspection reveals some much appreciated updates.  The headband no longer has bumps on the inside and is made of leather, the cable is detachable, and the earcups are extremely comfortable.  Many of the aspects appear to be "rehashed" from prior designed making many listeners skeptical or downright unhappy with the design choice.  For me it is more about judging a headphone on its own merits than knowing its history and making a preformed guess as to how they sound.  The design is solid from form, fit, and function.
 
From my iPod the test tracks were very involving and the improved bass was noticed.  I gave the K712 Pro an initial listen in my laser lab where things become quite noisy.  With my head deep inside the confines of my flow booth I had to set the volume to 70% which seemed pretty high for the advertised sensitivity and impedance.  Even on my home rig the BUDA remained on high gain and about set to 1/3 output.  That in mind they did sound quite good at this volume.  Things sounded great and the comfort improvements are huge in my book as I hardly noticed I was wearing headphones while working.
 
LET’S TEST THIS THING
Check Corea’s Three Ghouls, Part 1:  This track tests quickness, realism, and treble.  It also tests how up-front sounding a headphone can be.  The K712 Pro sounded full, quick, and perhaps a tad lean on the piano.  They lacked a little of the rough attack the headphones like the HD650 deliver with this track.  Then again the kick drum was much more realistic with the K712 Pro than the HD650.
Karsh Kale’s Longing is a track I use for general imaging and engagement.  As Tyll will tell you sometimes how a headphone makes you feel tells a lot about the headphone itself.  The separation and sense of space is just awesome with the K712 Pro.  From the bass to treble there is a very nice cohesion and fluidity making this track very enjoyable.  The K712 Pro sounds less tinny than the HD650 here and revealing to the sound image.
 
Maroon 5’s Won’t Go Home Without You:  This is a track I typically use to test crossover issues with speakers and IEMs.  It also gives rise to issues with male vocals and too up-front sounding headphones.  Most AKG K7xx headphones have some issues with up-front sounding drums and vocals.  I would say the K712 Pro is very similar sounding as the HD650 in this regard, but the airy bass on the K712 Pro is just awesome.  The K712 Pro is smoother than the HD650 on the vocals removing the edginess.
 
Michael Jacskon’s  Wanna Be Startin’ Somethin’:  Another track testing the up-front nature of headphones.  It also tests treble and vocals as with some headphones like the AH-D2000 and K701 can be harsh.  No doubt here even though the K712 Pro sounds nice with this track they are bright and up-front.  The HD650 removes the harshness at the cost of some realism in the bass guitar.  If you are an engineer looking to find issues with treble these are good headphones for that.  As for home listening the treble may find itself EQed down a bit.  Dropping 315Hz, 400Hz, as well as 3150Hz and 6kHz tamed the K712 Pro a bit.  No surprises here as this is what I typically view the sound signature of most AKG headphones.
 
Patricia Barber’s  Dansons la Gigue:  A great tack to test separation, bass, and female vocals.  A headphone like the Grado RS-1i struggles here as things become too one dimensional.  The bass blurs into the mids and further into the treble.   The richness of the guitar sounds spectacular with the K712 Pro.  It is possibly the best sounding dynamic headphone in this regard.  The HD650 begins to blur the guitar into the mids and there is a strange blurring of the vocals with the HD650 that I simply do not hear with the K712 Pro.  The K712 Pro is definitely a soft jazz headphone.
 
The Beach Boys’ Surfin’ USA is a track I use to test how even a headphone may sound.  Much like using Pink Noise it reveals any glaring issues like a lack of midrange smoothness, imaging, and even quickness.    The AKG K712 Pro removed the excess hiss on the letter “s” heard on the HD650.  Again here it was more about what headphone signature works well with the given track.  I liked the K712 Pro more as it sounded less colored and perhaps even laid back to that signature of the HD650.
 
They Might Be Giant’s Spiraling Shape is a track I use to test male vocals in detail, how the kick drum resonates, as well as test the metallic splash of the crash cymbal.  Here the HD650 sounded really colored compared to the AKG K712 Pro.  The Pro sounds much more even from the kick drum through the vocals.  The HD650 blurs the vocals into the bass.
 
If your music collection or production work consists more of acoustic guitar, drum, and vocals the K712 Pro scores excellently and would be my preference over the HD650.  For music like hard rock the Pro may wield a bit too much bite and up-front sounding midrange compared to the HD650.  As with many AKG headphones this will diminish slightly over time.
 
CONCLUSION
The AKG K712 Pro is a headphone that sounds very good and speaker-like.  The added bass is actually very impressive on particular tracks like Dream by Kroke.  Bass not found in the other AKG headphones that I have heard.  It is a headphone I find myself listening to over the HD650 at times because with certain tracks is sounds more full and pleasant.   In the end it is really about preference, but rest assured the AKG K712 Pro is an excellent and amazing sounding headphone.
 
At $499 I cannot help but feel that this headphone is on the expensive side.  In some areas it improves upon the sound of the HD650, but in other areas it remains hard to listen to due to the peaks at 2kHz, 7kHz, and 8kHz.  The build quality is really good and the headphone will look great with any home or production setup.  As others have mentioned if the price drops to $350 I think others including myself would be all over the K712 Pro, but at $499 you start looking at the Q701 and Momentum.  It definitely looks like AKG is targeting the somewhat lean $399 - $499 market, but I would like to see this headphone around $299-$399.
 
I also want to comment on the fit.  The K712 Pro is very comfortable and can be worn for hours without fatigue on the outer ear or top of the head.  The earcups rest a bit low on my head making me wish I could further adjust the headband.  The somewhat common issue with the elastic on the auto adjusting headband may wear out like their other headphones, but keeping good care of your cans should prevent that from happening.
 
My brief experience with the K712 Pro has been a good one and with more listening I imagine it will only improve.

FURTHER TESTING / ENJOYMENT
As with many headphones the more you listen to them the better they sound.  This is definitely true of the K712 Pro.  Listening to Photonic Phonic by Magic Sound Fabric via my iPod is extremely enjoyable.  The clarity, sense of space, and generous bass groove is very inviting.
 
Listening to Go Daddy-O by Big Bad Voodoo Daddy shows how quick the K712 Pro.  The cymbals are super quick and the horns are tame.  Again here the bass is something in balance rather than lacking.  These are quick!
 
John Williams' Christmans at Hogwarts is another pleasure.  The entire orchestra is in balance and the sense of space with the K712 Pro is very pleasing.
 
Mo' Horizon's Foto Viva is outstanding.  The engaging groove heard on the K712 Pro is very fun.
 
Pink Floyd's Goodbye Blue Sky is another track showing off the midrange and clarity of the K712 Pro.  The guitar is extremely realistic and the vocals are not lost.
 
Cello song by The Books sounds amazing.  The sense of space and the idiosyncrasies heard in the background are quite clear.
 
Daft Punk's Solar Sailer is a testament to how low this headphone can go.  There is some serious open rumble in this track and the K712 Pro is not shy to deliver.
 
I updated the overall rating from a 3.5 to a solid 4 because in many respects the K712 Pro is much more speaker-like than the HD650.
 
Vs. AKG Q701 and HD650
There is no doubt that there is something amiss with the Q701's midrange.  Piano, vocals, and the overall presence of the midrange on the K712 Pro is much more natural sounding.  The Q701 vocals, heard on Maroon 5's Won't Go Home Without You sound like they are coming through a mic that is coloring the midrange.  It simply does not sound natural at all.  Going from the Q701 to the K712 Pro is pleasing and reduces the listening fatigue from the Q701.  The bass boost on the K712 Pro is very much improved over the Q701.  The bass guitar is loud and clear instead of very recessed with the Q701.
 
On tracks like Patricia Barber's Dansons la Gigue the difference is subtle.  The vocals and bass are a bit more pronounces on the K712 Pro, but both sound very good. 
 
With Slaid Cleaves' Beautiful Thing the Q701 comes off as slightly harsher, but the K712 Pro smooths out the vocals just a touch more than desired.
 
Listening to They Might Be Giants' Spiraling shapes shows other similarities, but the Q701 has more obvious treble in vocals.  The echo in the vocals is easier to make out perhaps hidden slightly in the bass of the K712 Pro.
 
I decided to conduct a blind test using The Beach Boys' Surfin' USA.  Although it was pretty difficult to pin down which I preferred right away with a little time it became apparent that the K712 Pro had my preferred midrange.
 
The bass is really where I started to focus once the midrange differences were established.  Juno Reactor's God is God gave rise to some clear differences.  On my stereo system with a nicely tuned sub this track has some serious rumble.  Some headphones cannot reproduce the low end rumble this track delivers.  The Q701 sounded good here, but on the lean side.  The K712 Pro immediately produced better bass reproduction and rumble.  Listeners should know that the HD650 also bested the Q701 in the bass department.  If anything the HD650 has better resolution on this track than both.
 
This made me move onto Mike Clark's T's Boogaloo where the bass is a little more obvious and detailed.  Some of the air was missing on the HD650 in the very beginning.  The air is back using the Q701, but the slight thump the K712 Pro deliver is missing.  I have to believe that the emphasized bass is intentional in this track as almost every jazz / soul song I have ever heard in person has a slightly emphasized bass guitar.  It sounds more live with the K712 Pro.
 
The thunder in Dream Theater's A Nightmare To Remember has more body with the K712 Pro compared to the Q701.  The HD650 was much closer to the K712 Pro here and either suits this track well.
 
Vs. the Denon AH-D2000
The AH-D2000 is an excellent closed headphone and possibly the best I have listened to so far.  On tracks like Kate Havnevik's So:Lo the Denon is simply too boomy with bass bleeding all over the balance of the rest of the track.  This occurs again in Glenn Zervas' A Thousand Shades of White.  The low notes from the guitar are boomy on the Denon, but with the K712 Pro there is a very welcome balance to the sound.  At higher volumes ( just above long term levels ) Final Fantasy's None of You Will Ever See a Penny reveals a blury midrange image on the Denon while the K712 Pro has a slight brightness common with the K701 and Q701.  Something that a healthy -4dB EQ from 2kHz to 6kHz tames nicely.

The airy nature of the K712 Pro lends itself to tracks like MC 900 ft Jesus' Gracías Pepé whereas the Denon is lost and enclosed.

On Bluetech's Enter the Lovely the Denon added a slight coloring of the midrange sounding a bit tinny.  The AKG K712 Pro adds a nice digital rising edge to the beats heard at 2:58 unlike the Denon which feels decayed.  A fun track with both headphones, but the AKG K712 Pro is definitely the more neutral sounding.

My goal here is to compliment the bassy and somewhat fun sounding Denon with a more technically correct headphone like the K712 Pro.  Leave the thumping and enclosed tracks to the Denon and add air and crisp treble with the AKG.
 

Vs. the HE-500
Frequency Charts
http://graphs.headphone.com/graphCompare.php?graphType=0&graphID[]=4163&graphID[]=3241&scale=30
 
Pink Noise Test
Source:  Ayre Acoustic’s Irrational, But Efficacious CD
Compression: None
 
The AKG sounds peaky in the sub-bass and treble while the HE-500 is much more even across the entire frequency range.
 
Brown Noise Test
The AKG again has a peak in the sub-bass while the HE-500 is darker sounding which is what I would expect from the Brown downward slope in the frequency response.
 
Music Testing
 
Marcus Miller’s Gorée (Go-ray)
This is a great track for quickness heard in the cymbals.   It also tests for honkiness in the sax.
 
The HE-500 and K712 Pro both due quite well with this track.  The HE-500 adds some treble to the sound of the cymbals making them sound more metallic, but there is a blurring effect that keeps the cymbals from sounding their best.  The AKG K712 Pro is more up-front and reveals that harshness of some of the sax notes while the HE-500 smooths out the sax.  The sub-bass is more pronounced with the AKG K712 Pro, but the snap of bass string is lost with the HE-500.
 
Both headphones sound great with this track.  The HE-500 is more realistic with the cymbal splash while the AKG K712 Pro is more obvious with the sound of the bass guitar strings.
 
Dion’s Tarraplane Blues
This track tests male vocals, guitar, and the sound of decay within the drum machine.
 
The quick punch of the drum machine is swifter on the HE-500, but the AKG K712 Pro is just about as quick.  The vocals, being more up front on the K712, are more enjoyable and intimate compared to the HE-500.  Better matching the loudness brings the two headphones even closer together.  The sound of the drumstick hitting the side of the snare is more obvious on the HE-500, while obscured in the vocals on the AKG K712.
 
MC 900 ft Jesus’s Bill's Dream
A test track used to hear how real the drums sound and how much air is present.
 
The HE-500 sounds quicker on drums and less sub-bassy.  There is some treble extension on the K712 not heard on the HE-500 most noticeably on the pitter patter of the drum head and metal sound on the cymbals.   The HE-500 shades the cymbals and pushes the pitter patter of the drums too far back.
 
Mo´ Horizons’s Soho Vibes
A track that testing everything from bass to cymbals with emphasis on the midrange vibes.
 
This track has the clearest difference between the two headphone other than the pink noise.  The HE-500 hides the metal splash of the cymbals within the sound of the vibes.  There is also a ringing sensation on the vibes with the HE-500 not heard with the K712.  The echo from the drumstick hitting the side of the snare is more rounded and smooth with the K712 and square wave sounding with the HE-500.
 
Conclusions:
Both headphones are commendable.  The HE-500 flat throughout the frequency response, but at times square wave sounding with analog instruments and blurring treble into the midrange at times.  The sub-bass peak of the K712 is very obvious on many tracks, but often presents cymbals and vocals in a more pleasing way.  There are more signs of echoes and other positional cues on the K712 than the HE-500.
 
For the price the AKG K712 Pro does quite well against the more expensive HE-500.  The sub-bass is the main problem for the AKG while the HE-500 tends to hide detail and positioning cues.   The HE-500 begins to reveal these cues at volumes above which I am comfortable listening.
The HE-500 reminds me of the HD650 sans the added treble.  It is an easy going headphone while the AKG is more up-front.
 
Additional testing:
None of You Will Ever See a Penny by Final Fantasy reveals how the HE-500 hides the sound of the reverberation of the stringed instruments while the AKG presents a more hollow and lively sound.  The HE-500 sounding square wave in nature with no decay.
 

Vs. the modified Sennheiser HD800

Mod reference: http://www.innerfidelity.com/content/diy-modification-sennheiser-hd-800-anaxilus-mod

 

I borrowed this modified HD800 from Tyll and although he thinks the mod does not drastically change the sound of the HD800, he does admit that it plays a key roll in getting the most out of a pair of stock HD800 headphones.

 

To me the stock HD800 is a bit digital sounding, Tyll uses the term “steely”.  It sounds almost too quick and trebly at times.

 

Pink Noise

I use pink noise to find peaks or valleys in the frequency response.  If something stands out or becomes harsh in using pink noise chances are it will sound that way when listening to music.

 

The HD800 sounds very smooth below 500Hz, but there is a definite peak somewhere above 500Hz that my ear is picking up on as fatiguing.  Compared to the K712 Pro which sounds much more even in the treble, but the sub-bass component is prominent.  Here it seems is a flavor choice.

 

Using Quentin Dujardin’s track 1977 I shift my focus to music listening.  The K712 Pro is very musical, sweet sounding with the guitar plucks and the wisps of ambience which appear to be the artist breathing.  The treble is very nicely neutral and the location cues from the treble are very easy to home in on.  The guitar string sound is moved to the background with the K712 Pro and obscured compared to the HD800.  I hear more of the resonance of the guitar body rather than the pluck of the strings with the K712 Pro whereas the strings are much more focused with the HD800.  The HD800 is easier to listen to with this track.

 

Using Mike Murray’s Hello Market track I move onto dynamics.   The resolving power of the HD800 and soundstage is simply amazing with the HD800.  The separation of each instrument is lost with the K712 Pro and again we hear a blurring of the midrange.  I cannot help but think that the modded HD800 softens the entire frequency spectrum compared to the K712 Pro making it easier to listen to on this track.

 

Starting up Bluetech’s Enter the Lovely track reveals other differences.  The HD800 brings immediate focus on the ticking with some brightness felt.  I hear more resonance on the ticks with the K712 Pro.  The K712 Pro emphasizes the lower frequencies more than the HD800, while the HD800 is focused on the midrange.  The K712 Pro has a definite sub-bass emphasis compared to the HD800 giving it more body there, but it still sounds blurry compared to the HD800.

 

The last track I compared these headphones with is MC 900 ft Jesus’ Gracías Pepé.  The airiness of this track is lost using the HD800.  It sounds like the HD800 has more treble focus and smooths out the track by removing some of the harmonics in the midrange frequencies.  This track makes the two headphones sound surprisingly similar which is a good think for the much less expensive K712 Pro.  I have no preference on this track.  Again this is coming down to focus.  The HD800 focused on attack and treble separation while the K712 Pro is more midrange centered and revealing in airiness.

 

The HD800 appears to have fewer reflections in its resonance making it very revealing and resolving.  The K712 Pro is blurry by comparison.  The primary differences between these two headphones are the resolving power of the HD800, the sub-bass impact of the K712 Pro, and the blurring of the midrange on the K712 Pro.  If money were no object I would easily go for the HD800.  Everything from my reference collection I throw at it sounds amazing.  The K712 Pro does a great job, but compared to the HD800 one can hear the blurring.

 
HOW DOES ORCHESTRAL SOUND WITH THE K712 PRO?
Giuseppe Sinopoli and The New York Philharmonic's Pictures At an Exhibition sounds very full, realistic, and wonderful with the K712.  The reverberation of the brass, the kind thump of the bass, and even the horns are all in place.
 
Moving onto the Les Sylphides VIII: Valse by the Berliner Philharmoniker Herbert von Karajan is elegant, pleasing, and truly mastered by the K712.  The fullness of the track along with the minute idiosyncrasies heard are put to good use with the K712.
 
Leopold Stokowski and the original Decca recordings 1965-1972 of JS Bach's Prelude in E-Flat Minor is simply stunning with the K712 Pro.  Full, vibrant, and well balanced throughout this track is something that really drives emotion.  Nothing sounds out of place, but I feel that the strings are uneven sounding and unrealistic with this track.  I do think it is more the recording than how the K712 reveals the strings to be.  The Dialogue of the Wind and the Sea from this album is also worth a listen.  The imaging is spectacular and the low bass rumble is something not commonly heard with other headphones.
 
Alaine Fink and George Vosburgh's Intrada for Trumpet and Piano is quite mellow for such a vivid trumpet piece.  The imaging for the piano is also quite good and not lost among the trumpet's more in your face attitude.
 
Moving into a vocal recordings I started up Veronique Gens' Mass in B Minor, BWV 232: Laudamaus.  Again the detail and the hints of echo, the vibration of the strings, and the closeness of the vocals were all amazingly reproduced with the K712.
 
The English Suite No. 2 in A Minor, BWV 807: V.Bouree I/II by JS Bach from Menuetto Classics is about as close to a harpsichord as I have ever been.  I felt as if I was there when it was played.  The Suite for Violoncello Solo No. 1 in G Major, BWV 1007: I, Prelude by JS Bach is another extremely realistic piece on the K712.  This track is a must have for classical listeners!  The Complete Cello Suites from Klaus-Peter Hahn is really a bargain and well worth looking into if you want to round out your collection.
 
I think the K712 Pro is an excellent if not amazing headphone for classical listening.  It adds a sense of vibrance, life, and detail not heard in many other headphones.
 
WHICH DO I PREFER AND WHY?
I must say the K712 Pro holds its own.  It may be bassy on some tracks, but to me this is a good thing.  The pleasing midrange is extremely easy to listen to and discernibly more even than that of the Q701.  On some tracks the Q701 is more airy with a definite issue with the midrange.  The HD650 and K712 Pro trade off every other track I throw at them as to which I prefer, but on the occasional track the HD650 sounds strangely thin in the bass.  If you are looking for a more budget headphone the HD650 can often be found on sale making it truly enticing.  The K712 Pro offers better clarity and a less blurry image on the low end.  The Q701 has some issues with the midrange and slight lack of bass.
 
Need a track to figure which you prefer?  Try Medeski, Martin & Wood's Chubb Sub.  The bass is ever so slightly blurry with the HD650.  The slight harshness of the Q701 also blurs the low end.
 
All three are excellent headphones and this test really brings it home how great each is in their own right.  To me the K712 Pro does what the others strive for only better.
 
IS IT JUST THE PADS THAT CHANGE THE SOUND?
I tested the Q701 and K712 Pro without pads.  I simply left off the pads of each and did immediate swap testing.  My BUDA continuously drives both headphones during this test.  It looks like the drivers are the same, but the resonator is different.  The Q701 has a noticeably different and somewhat tinny sounding midrange compared to the K712 Pro.  Both sound much closer to one another than I initially thought would be the case suggesting that there is no doubt benefit to the new pads.  To my ears the change in sound is more than just the pads, but the pads make the biggest difference.  With the K712 Pro pads on the Q701 there is more meat to the bass, but the mids did not sound quite right.
 
The AKG K712 Pro still sounds its best with the K712 Pro pads, but if you want a poor-mans version of the K712 Pro adding these pads to existing Q701 / K701 will get you very close.
 
I did this testing with Marcus Miller's Redemption and Mo' Horizons' Foto Viva.  It took me these tracks to start hearing the differences.  I think initially I had the Q701 pads installed incorrectly as it sounded worse.  I installed the pads on the Q701 with the thicker side facing back and the Q701 returned to its former glory.  Again it came down to how much meat was on the low end and something in the mid range on the Q701 is tinny in comparison, but it is close.
 
A FEW OTHER TRACKS OF NOTE
Emiliana Torrini's Ha-Ha ( Vocals )
Santiago Vazquez's Azul Sangre ( Neutrality and soundstage )
The Doobie Brothers's A Brighter Day ( Quickness on drums, bass guitar )
Thelonious Monk's Rhythm-A-Ning ( Speed, Jazz )
 
2016 Update
After much debate I decided to include a long-term listening update. The primary idea behind this is to give a brief review of the AKG K712 Pro after owning it for years. The score of this entire review has been adjusted due to this update.
 
Due to the rather weak adjustment system on the K712 Pro the fit comfort score has been lowered. Several users including myself find that the earcups rest too low on the ears not only making it uncomfortable, but the sound suffers too.
 
The price seems high considering it is a tuning of the K701(2). It would have been an excellent choice to add a few more dB of bass to separate it from the other K7yy line of headphones.
 
With planars like the HiFiMAN HE-400s and HE-400i within the price point of the K712 Pro it is hard to recommend. These planars sound more coherent, have larger drivers, are more comfortable, and deliver deep linear bass.

published on January 19, 2014

 
- download a printable 3-page PDF version of this review (link goes to a location on my Dropbox)
 

(click for larger photo)
 
Intro
 
This is basically a short mini-review of the AKG K712 from while I owned it for a few weeks in December 2013 through January 2014.
 
Equipment Setup
 
- Source components: NAD T533 (DVD player)
- Headphone amplifiers: HeadAmp Gilmore Lite w/ DPS, Garage1217 Project Ember
- Comparison headphones: Audio-Technica ATH-AD2000 & ATH-AD2000X, Sennheiser HD598, Shure SRH1540
 
Evaluation Music
 
- Boards of Canada - Tomorrow's Harvest
- Carlos Kleiber & VPO - Beethoven 5 & 7
- Erin Boheme - What Love Is
- Half Moon Run - Dark Eyes
- In Flames - The Jester Race
- Julia Fischer - Bach Concertos, Paganini: 24 Caprices
- Katy Perry - Prism
- Massive Attack - Mezzanine
- OSI - Fire Make Thunder
- Phantogram - Eyelid Movies
- Sarah Jarosz - Build Me Up From Bones
- The Civil Wars - The Civil Wars
- The Devin Townsend Project - Deconstruction
- Yggdrasil - Prose Edda
 
Amplification
 
Most headphones tend to sound good enough on just about any amp, and although I wasn't able to test the K712 on any "budget"-level amps, I'd imagine that to be case with them as well. I'd say that anyone planning on buying the K712 should definitely factor in a dedicated amp for them, even if it's just a cheap one, as it's one of those headphones that really comes alive the better it's amped and requires high current & voltage in order to start sounding especially good. Case in point from my own system: the Gilmore Lite amped the K712 moderately well and didn’t reveal any audible sonic issues at low to moderate volumes, but at anything close to high volumes it started disproportionately subtracting the bass & mid-bass, leaving mostly only the mid-range and treble intact which resulted in a distinctly unbalanced sound. The Project Ember with the right tube (a 12AX7VKA), on the other hand, was able to push the K712 to high volume without any sonic subtractions and proportionately preserved bass quantity.
 
And the K712 sounded downright amazing on the Project Ember w/ 12AX7VKA, much better than it did on the Gilmore Lite. In fact, it was so good that I could've easily considered the K712 & Project Ember combo to be a "final" end-game setup, and in a lot of ways I vastly preferred its sound over other dynamic and planar magnetic headphones that I've previously heard, including the Sennheiser HD800 and Audeze LCD-2/LCD-3. Of course there are some aspects that I consider the Sennheiser and Audeze flagships to do better in, but overall the K712 was surprisingly awesome-sounding and held its own against the vastly more expensive flagships. The Project Ember (using a proper high-gain tube) is definitely an amp pairing that I’d recommend too.
 
Comparison to: Sennheiser HD598
 
Compared to the HD598, the K712's soundstaging felt more concentrated and continuous, but also more closed-in. The HD598 had a great "out & away" type of soundstage to really provide an illusion that music was occurring a good virtual distance away, but the K712 took sort of an opposite approach and brought everything forward more, closing the distance gap so to speak, but still sounding very open, separated, spread-out, & wide. In a very loose sense, I'd say that the HD598's soundstaging was quite similar to the HD800's in sounding "out & away", which I thought was overdone on the HD800 and made it sound unnaturally large & diffuse. The smaller-scale soundstaging of the K712 came across as more realistic to me and not as over-the-top as the HD800.
 
The K712 also had a better tonal balance to me, fleshing out the mid-range a bit more (specifically the vocal range) though it was somewhat at the expense of treble quantity. The HD598 had more treble quantity in comparison. Neither headphone had much bass, though the K712 did seem to have slightly more quantity throughout the 30-200Hz range. And despite having more bass quantity, the K712 was very "controlled-sounding" and was never boomy, flabby, or too thick. Its bass was always clear, distinct, & taut and was more rhythmic than deep. But probably the biggest difference between the K712 and HD598 was the way in which the K712 presented a cohesive sonic image that included left, center, & right (the HD598 sounded as if it had a hole in the center) and presented the music as if it were right in front of you (not away from you, as the HD598 did), with more physical tactility as well. Sort of unexplainable but the K712 simply made vocals, female in particular, sound physically present and very much in-front-of-you while the HD598 lacked that presence factor.
 
I'd describe the K712 as a moderately-detailed headphone with a good level of clarity (not as good as the HD800 in that aspect, which I consider to be one of the clearest-sounding dynamic headphones), a wide & open soundstage (smaller than the HD800's but probably larger than most other headphones), and some marginal lack of lower mid-range, mid-bass, & low bass. That is, it wasn't what I consider heavy- or thick-sounding, and I wouldn't call it very appropriate for music that relies on bass and/or overdriven guitars like metal or hard/heavy/prog rock, or low-pitched male vocals. The K712 seemed to be at its best with classical and generally acoustic music, and less good with music that involved a lot of electric or synthesized instruments, though I could definitely see others liking it for rock, metal, & electronica too, depending on sonic preferences.
 
Indirect Comparisons: K7xx, HD800
 
I can't say with certainty how the K712 compares to AKG's previous K7xx headphones, but as a previous owner of the original K701, original K702, and K702 65th Anniversary, it did seem to have the most balanced sound that I've heard out of AKG's K7xx line with the most amount of bass as well. I always considered the K701, K702, and K702 65th Anniversary to lack a convincing physical sound, and the K712 seemed to retain a trace of that characteristic as well, but it did seem to have the most physical presence, particularly when playing female vocals. But most importantly, and the reason why I went with the K712 instead of the Q701, was because of the headband. I've always disliked AKG's bumped headbands on their K7xx headphones and was glad to finally see the bumps removed on the K712.
 
I was never very impressed by the HD800 despite the fair shake I tried to give it on various amps that included the HeadAmp GS-X (MK1), Luxman P-1u, SPL Auditor, Schiit Lyr, Avenson Audio Headphone Amp, and a Rockhopper-built M3. Regardless of the amp I used, the HD800 always lacked mid-range to me and had too much treble quantity as well, and the only music that I could remotely tolerate it for was ambient electronica, bluegrass/folk, and generally acoustic, female vocal-based music. Although many others have said that the HD800 works well with classical music, I personally could never get past its torturous treatment of violins specifically, as it just made them too fake- & wispy-sounding, and I'm saying that as a violinist.
 
The K712, on the other hand, made violins sound much more realistic to me with a lot less of the glossy & wispy signature of the HD800, and its smaller-scale soundstaging came across as more convincing as well, with large studio-type acoustics instead of the extra-large auditorium acoustics of the HD800. It was also way more musically dynamic to me and conveyed the subtle transitions between piano (p) and forte (f) properly, including sforzandos, which the HD800 never did on any amp that I tried.
 
To the HD800's credit, I do view it as the vastly clearer-sounding headphone with a nicely refined treble and distinct & deep bass, but for me it was just never able to convey proper tonal depth & musical dynamism. The K712's higher mid-range quantity and greater dynamic range provided that for me, and because of that I'd call the K712 more musically versatile than the HD800, and in a few important ways, distinctly superior. Yes, I am indeed saying that a $500 headphone can subjectively sound better than a $1500 headphone in certain ways!
 
Summary
 
The K712 wasn't perfect to me—no headphone ever is—but it sure was a surprise, even after all the headphones I've gotten since 2006, when I got the original K701. I would've liked it more if it had a bit more upper treble quantity, along with more quantity in the lower mid-range, mid-bass, & low bass (particularly in the 30-50Hz range), but I still really enjoyed it overall and got more musical satisfaction out of it than I ever did with the HD800 and LCD-2/LCD-3.
 
Although I do think AKG has been over-milking the K7xx line for far too long, the K712 was easily the best-sounding K7xx to me and I think a lot of other people would be surprised by it as well. Certainly not for everyone but it's probably worth a try, especially for those who haven't yet heard an AKG K7xx.

First, a disclaimer: I am running these off my laptop through a FiiO Q1 as a DAC and a Schiit Magni 3. These are not high-end amps, but if you don't already own really expensive equipment and your budget is less than exorbitant maybe you will be running them through similar equipment. There's been much ado about how these headphones need high-quality amplification to sound their best, so some of the problems I'm about to describe may be ameliorated somewhat with different equipment, and from some of these reviews, it sounds like this is true.

Comfort, looks, etc.: I don't typically have issues with comfort, but I will say that out of all the headphones I've tried these are by far the most comfortable. The clamping is enough to prevent them from shifting (on my head), but light enough that they never press too hard. The headband is comfortable enough that I hardly feel it most of the time. As a bonus, I like the way they look, but this is of course a personal preference and you can look up images yourself if you want. I wouldn't say the earpads are terribly soft, but they are again very comfy. Build is mostly plastic, as others have said, but I don't care about this at all; if you really need headphones with a lot of metal to feel good about yourself, perhaps you should look elsewhere.

Bass: No issues for me with quantity or quality. It's tight enough that I've never really had any issues at all with poor resolution or distortion. Others have said that the bass is pretty much perfect on these; they may be a bit on the bassy side but I've never had any issues with this either. There is a bump towards the upper end of the bass that extends into the lower mids; while this doesn't translate into muddiness it may bother some people who want a leaner or airier bass presentation.

Mids: As with the upper bass, the lower mids are forward, resulting in a tone that's overall warm (but not dark). I prefer a warmer tone, so this area is perfect for me. They sound full, never thin or empty. The upper mids are where the problems start to creep in - as has always been the case for the K7s, there is an interesting bump at around 2kHz. I listen to a lot of vaporwave, and with the way a lot of these tracks are mastered, this area already emphasized, making the listening experience for these tracks quite painful at times. Without EQ, anytime this area of the frequency spectrum is busy or congested at all, you will notice it, and the K712 will exacerbate the issue. I have EQ'd this area down slightly (2-3 dB from about 1850 to 2300) and it makes the headphones sound less energetic but more natural. Luckily this spot doesn't seem terribly slow, because they respond pretty well to the EQ. At times this bump can be welcome in that it gives certain instruments (guitar, some percussion) more energy / presence. But it is there and that isn't going to change.

Treble: This is the area that really gave me a lot of trouble when I first got these. I have heard that higher-quality equipment can smooth out the treble consistently, but with what I'm using, I got quite a bit of sibilance from especially modern pop recordings: any time vocals were mastered with the intent of making them more "present" / "intimate" (which seems to be done often by boosting a certain area of the treble to reveal the "grain" of the voice) the listening experience would get quite overbearing and piercing. The same goes for some recordings with a lot of cymbals or percussion in general. For me, cutting around 9.5-10.3kHz more or less controlled these issues, but I've heard reports of different peaks for different pairs; 11kHz for some, 9 for others. If you buy these I would recommend sweeping this area to see where the glare seems to be located. Other than this, the treble is pretty resolving and clean, though you may notice some grain if you don't fix the spike(s). Obviously a high-quality source is basically required for these; unlike some more forgiving headphones, any deficiencies in quality are going to be noticeable here.

Soundstage: This is why I bought these, and they certainly delivered; the soundstage is wide, with pretty excellent imaging, but never feels too diffuse or forced. If you really want an "intimate" soundstage, these are not for you and you should look elsewhere; what you're paying for when you buy these is an experience of space, and that's what you get. For me, however, the wideness of the soundstage and perceived distance of certain sounds results in me listening to music louder, so that's something to be aware of. However, for me, the was pretty much perfect and exactly what I wanted. Great for classical music; really great for field recordings and ambient, which are my genres of choice; really good for jazz, and other live recordings.

Overall: After (not really drastic at all) EQ, the K712 is pretty much exactly what I wanted, but before EQ, it could be shrill and harsh especially with some genres that I listened to frequently. Even after EQ, it is pretty unforgiving of bad recordings or sound quality, but when something is well-recorded and especially suited for the K712's strengths - width, dynamic range, a sense of naturalness - the result is breathtaking.

But the K712 does sort of seem to be suffering a kind of identity crisis of sorts. The earlier members of the K7 series were criticized for their clinical, thin sound; the K712, along with some of the other later members of the family, have made up for this by boosting the upper bass and lower mids to make the headphones sound warmer and fuller-bodied. Despite these alterations, the K712's have retained the upper-mid bump and sometimes peaky, bright treble of the earlier headphones (though apparently to a slightly lesser degree) as a sort of signature component of the more recent AKG sound. At first, I was pretty confused by this, as I noticed that despite the overall warm sound of the headphones they were quite fatiguing to listen to for longer periods of time. While the combination of bright treble and present upper mids with warm lower mids and bass may be a bit odd-sounding, it does mean that these are great all-rounders and usable for a lot of different kinds of music.

Conclusion: Despite some issues with the treble and upper mids, I'd recommend these to anyone who's looking for a pair with a wide soundstage and who's either unafraid of brightness (these are still going to be less harsh than anything by Beyerdynamic, for example) or who's unafraid to EQ when necessary. They're really, really great, the best I've used, but I'm still on the road looking for that magic "perfect pair."

Once the treble weirdness is fixed, these really are fantastic, resolving, spacious headphones that do everything I can think of really well. Again, they are not for everybody, but I find myself liking them more and more. Yet for all my love of these headphones, they lack the kind of spark that makes me truly fall in love with them. For reference, I find myself slightly preferring the K553's - despite the fact that they're technically inferior (except for their FR, which is more neutral), they seem to have slightly more character in some way. I would recommend the K712 for anyone, but for me it's not truly inspirational.

Also, a note: if you are buying these used for $300 or more, you're wasting money, as they are available from Europe for under $200. I bought mine for about $190 (with shipping it came to about $220 as I needed them shipped fast in advance of a move).

Final verdict from me (intro):
 
Originally I had listened to the K712s on a Yulong U100 and they were the most expensive headphones I'd ever used. I was dissatisfied but I didn't feel it was fair. I don't want to be the guy running in frantically, waving his arms, talking complete nonsense. 
 
I have spent plenty of time with these headphones now. I have A/B'd them with a the Avid Omni HD, Yulong U100, Yulong DA8 (through the headphone out and via the Denon PMA-750) as well as straight out of my Galaxy S Note II. I've pitted them against the Sennheiser HD280, Sennheiser HD25-II, and the Hifiman HE-6.
 
Look and Feel:
 
I think these headphones look great. They would be comfortable but my head is too small for them, they droop down the sides of my head. The pads are easy to replace and the cables are easy to swap.
 
No physical issues IMO.
 
Sound:
 
 
I spent an hour writing garbage and then re-listened. The bottom line is I don't like the K712s' boosted bass, I also think the 2k peak (creating a sort of aggressive immediacy is a choice that needs to be considered). Properly amped I liked the K712s but they still sound like headphones against the HE-6's. They sound notably lower quality when it comes to better recordings, but they're decent headphones (even if they feel like they're struggling to reproduce music sometimes instead of just being a window). They aren't sibilant in the treble at all, despite what I previously felt.
 
I give them a 7 because I don't love them but they're not bad. 

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Introduction:
AKG, formed in 1947 has its strong dominance in the professional audio industry since decades. From a vast catalog of studio microphones and studio monitoring headphones, we are going to take a look at the revered K712 Pro which is second in line only to their flagship K- Series headphones, the K812.

The K712 Pro retails for 499$ and is frequently available for 350$.


Specification:

• DRIVER TYPE- DYNAMIC.
• DESIGN- OVER EAR.
• EARCUP STYLE- OPEN BACK.
• FREQUENCY RESPONSE- 10 HZ TO 39.8 KHZ.
• SENSITIVITY- 105 DB.
• IMPEDANCE- 62 OHMS.
• MAXIMUM POWER HANDLING- 200 MW.
• CONNECTOR- 3 PIN XLR (UNBALANCED) TO 3.5 MM WITH 1/4'' ADAPTER.

Gear Used & Tracklist:
Denon DCM500AE as CD Transport | Schiit Modi 3 | Schiit Loki | Schiit Magni 3 | Aune X1S | iBasso DX160.




Unboxing:
The headphones come in a black carboard box with a velcro lid. Inside which we find the headphones, a high quality black velvet carry pouch, two cables - a black coiled cable and an orange 3 m straight cables, both having the screw on capability for the included 1/4'' adapter.

The unit which we are reviewing today is the one made in Slovakia.


Scalability:
Scalability for this headphone is very high. . On Magni 3 high gain, the knob needs to be kept at around 11-12 o' clock almost all the time. In quiet recordings, the knob needs to be turned all the way to 2 o' clock. The headphones have been tested on the Aune X1S Headphone Amplifier (on high gain) and iBasso DX160 DAP and neither of the two have enough power to drive it properly. When under powered, the K712 Pro sounds thin and harsh with almost non existent low end.

A considerably powerful desktop amp is absolutely necessary for the K712 Pro to drive it properly even though the sensitivity and impedance are not indicative of such power demands.




Fit:
The suspension headband has no issues and helps in distributing the weight evenly. The pads are massive in size and no part of the ear touches the sides of the pads. I suspect the same for everyone's ears. The pads are plush velour filled with memory foam, they do not cause hot spots or get sweaty for me and conform as expected. The gripe being that the pads are not as deep as I'd like. I have small ears and they always touch the insides. It does not touch the driver directly as it is damped. Thankfully AKG has the pads netted inside to make the experience just a bit more comfortable.









The intro of Flight To LAPD sounds very satisfying on the K712 Pro with enough presence, in stock form. Most open back headphones sound thin and downright skip frequencies that low.

The deep rumble is brought out better when subbass is EQ'd. The stuffy and stabbing electronica in the background of Pulk/Pull Revolving Doors throughout are enveloping and have clean and strong attack. The bass notes in Another One Bites The Dust are absolutely clean and tight, tastefully done. Separation from the vocals is stupendous and yet it manages to be omnipresent.





Listening to this song on this headphone is not a pleasant experience due to its shouty upper midrange. The guitars have a ear ringing glare which is deeply unpleasant after a minute.





Money For Nothing having a "clinical" sounding master is not an ideal pair with this headphone. The experience sounds too digital, lacking life. I would describe the experience of listening to the Lindsey Stirling tracks as a system shock. The violin sounds lush, soulful and full of energy. Detail retrieval and texture in this region is very good. Its intimacy almost tricks the listener into being on the stage. The thumping bass cutting in from the background makes for a complete and beautiful experience.




The writing on the board in Letter is accurate throughout but the fuzziness diagonally front is easily noticeable. The intro of Across The River depicts the depth in stage when the instruments are introduced in the mix at different distances from the listener. The Magni 3, although doing a good job, a higher quality amp will bring about the layering as more three dimensional.





All the instruments in the mix of Once Upon A Time In The West are laid bare left-right across the soundstage with crisp and well defined edges. The separation along the center image is reproduced clearly giving a vivid sense of space. The separation along the center image in Three O'Clock Blues is also made clear in this song at around the 2:50 mark. The cymbals crashing (very) slightly to the left and right alternately are heard clear with admirable well defined edges.





The song Right Action comes out a bit too eager and "in your face" because of it's mastering. When heard through the K712, the experience can get a bit overwhelming sometimes. Snare hits sometimes sound aggressive and electric guitars too crunchy. The experience of hearing Marry You through the K712 is nothing short of majestic. It is lively, dynamic and feels like being in the front row seats. The snare hits and cymbal crashes never sound sibilant or sharp in any way. Eric Clapton and BB King are outlined clearly in the mix. The stage is wide and the "oomph" factor seems to be amplified.




Both great songs to test vocal performance, texture in the vocals are brought about immaculately, including the breath of the vocalists on the mic. The hoarseness, strain and breathlessness in the voices are lifelike and intimate. Absolutely no complaints.



Sax, Pianos, Violins, Hammond Organs have a soulful rendition full of life and body, sounding lush. They never appear to be distant with respect to vocals or the sax. Decay of snares and tom drums are not cut off in the track Take Five and are replicated accurately, giving a sense of realism and recording space.



Conclusion:
The K712 Pro is a technically sound headphone. Its drivers are very capable, fast and clean.

The review has been conducted in stock form but all the sonic gripes can be fixed and even enhanced by EQ. The subbass can be cranked up and the upper midrange can be toned down and the headphone responds remarkably well, making the headphone near about perfect from an enjoyment standpoint.

People looking for a headphone that is fun and exciting to listen to should really shortlist the K712 Pro, provided they have a beefy and capable amp to drive these cans to their full potential.




*All ratings are accurate as of date of publication. Changes in price, newer models may affect Project A3's views on the performance and value of the reviewed product.

I have these headphones for about 3 weeks and I think they are great for overall listening to music, even for a long time, however, I don't think you can drive them without an amplifier because the audio quality from a phone or just a poor build-in dac isn't good, the bass sounds muddy and the highs lack detail.

So I've got the Magni 2 and Little Dot 1+(Mullard M8100 tubes,OPA2107 op amp) and I must say that the Magni feels like the inferior amp for this headphone the bass has less impact, the soundstage is smaller, has less detail although it has more bass and the presentation feels faster. It looks like the tubes add a little impact and smoothness.

Overall, these might be good as a second pair if you already have like a Sennheiser 600 series headphone (I have HD 580s) or if you want something different, but I don't recommend them as a first pair for people that don't know what they're going into (try out an akg open-back headphone before deciding to buy)

Anyway I got these for cheap (they are made where I live) and I keep them for sure.

8/10

Before buying you should know that sometimes(maybe a first revision or something) the K712 has a loose wire on the left ear. My first pair had this problem (sound from the left ear was gone after the first day of use) but thank god the second pair I got is fine(for now).

This will be a somewhat compact review and comparison to the HiFiMAN HE-400, they're roughly the same price around here. Starting with some pictures.
 

 

 

 

 

 
Accessories
While I don't consider accessories that important I guess I should mention them. K712 comes with a straight and a coiled cable, 6,3mm adapter, and a carrying pouch.
HE-400 comes with the stock cable, 6,3mm adapter and a carrying pouch.
 
Comfort
The comfort of the K712 is good. The headphones weight is 235g which is very light considering their size. The self adjusting headband works well and the earpads feel nice on the skin. I don't think the fit is too loose despite having a small head. During the first hours of use there is some pressure building up on the head from the headband, but that disappears after a while when it adapts to your skull.
Compared to the HE-400 they're obviously much lighter, HE-400 weights 440 grams which is almost double up. The headband on the HE-400 is very well designed though, and I don't have any comfort problems with them. So apart from bulkiness HE-400 is just as comfortable. Both stock earpads are fine too although I know some people don't like the HE-400 pleather pads, if that's the case then you probably like the K712 pads more which is soft memory foam.
 
Build quality
While the build quality in general is good, the K712 does feel a bit plastic considering the price. Especially the bows that connect the cups feel very fragile. The headband and cups themselves are good though, and the mini XLR connector for the cable works well. The stock cables that come with it are good.
In comparison the HE-400 is built like a tank, but the coaxial RF connectors are bad and the stock cable is extremely bulky.
 
Sound
 
Sources: CA Dacmagic Plus DAC, Lake People G109-S headphone amp
Files: My own FLAC library and some Spotify Premium streaming
 
First I'll focus on the K712 and after that a comparison.
 
As a whole, the sound provided by the K712 is impressive. I never really find it to offend or do something bad. It does expose bad recordings though, no way around that.
The bass is very well controlled. With music where slam in the bass is not intended you get none, zero. However, try turning up some Infected Mushroom or Ludacris and you will be treated with some serious rumbling or impact, depending on the song (for an open headphone). The presentation is very convincing on "Ludacris - How Low", I can dig out all the low frequency details in the background and the rapping is in perfect balance with the beat. With "Koan's - Selena's Song" it's very easy close your eyes and be carried away by the firm bassline backed up by the deeper rumbling and the ambient sounds, I imagine this is very close to how the artist wanted it to be.
Varieties of rock is probably their strongest point for me though. The balanced yet slightly warm presentation together with the rather wide soundstage is a real winner. In "Dayshell - Avatar" I can separate instruments very well and get a sense of how the song was recorded, but it doesn't get too analytical, it's very easy to still simply "enjoy the ride". 
With metal you do run into this problem where a large portion of the music is rather badly recorded and mastered, and the K712 does expose it quite effectively. When it's good it's really good though, as an example my In Flames Clayman and Reroute To Remain rips sound brilliant. I do occasionally wish the drums had a bit more "kick" in them though, something the HE-400 has spoiled me in.
The K712 does vocals so well that I can really appreciate music like Celine Dion's despite I don't normally have any interest in it. Material like the old Nightwish with Tarja Turunen sounds fantastic.
Regarding the treble there isn't much to point out. It's smooth, it's good. No fatigue, no emphasized sibilance, amount is just right.
 
Not much to add. But yeah the sound is great. To counter all this praise, I do find the sound gets a bit "too secure" sometimes. It's like, you listen, and you know it sounds great, yet it's a bit boring at the same time. But that's probably inevitable with something that performs so even. I think a 4/5 star rating is fair, could maybe be 4½, but it loses a bit on the build quality, and on price. I haven't actually compared it to the older models, but if there really are changes made that qualify a ~250€ rise in price I think AKG should make that more clear. On the other hand, they clearly compete with the HE-400 that are priced similarly, so...
 
Comparison to the HE-400
When you compare these two headphones, the weird V-shaped frequency response of the HE-400 is very noticeable. The HE-400 has a great bass presentation in my opinion, and the texture on drums is brilliant. On the same time, this combined with the rather small soundstage gives you this very intimate and warm sound that can be a bit too much. Vocals also sound a bit strange on the HE-400 when compared to the K712, this is probably related to the dip between 5-6 KHz. HE-400 also has slightly more emphasis on treble, especially sparkling sounds like cymbals, sometimes this works out great, sometimes less so. HE-400 definitely has a higher fun factor, so this does boil down to taste. I would still say though that the rock solid performance of the K712 makes it better overall. There is slightly more sibilance on the HE-400.
 
AKG K712: Is more neutral, has a larger soundstage, is an more even performer.
HE-400: More bass impact, slightly more treble, does some material very well while falling short on other, more forgiving with bad recordings

Overall great headphone. Love lightness+comfort. Very clear sound with great highs, lows and slightly less pronounced mids. Sweet open sound stage. 

Allow me to preface this review with some background information.
 
I have experience listening to different present-day AKGs, including the Q701 Quincy Jones Signature, the K702 65th Anniversary Edition (Austrian-made), the K7XX Massdrop First Edition, the K240 Studio, and the K612 Pro. The K7-Series, while highly detailed and comfortable, proved to be a mixed bag for me sonically, with the models being either too intimate sounding, too mid-forward, or too dark. I did believe that these flaws belied a truly great-sounding headphone lurking beneath, but it was simply a matter of sorting out the right acoustic balance. And now I can say for sure that the K712 Pro hits the mark dead on for me, and has become my new favorite neutral open-back headphone. Now onto the review.
 
Build and Finish:
 
The K712 Pro resembles the K702 65th Anniversary (Annie) in many ways, from the charcoal-colored matte plastic body, to the colored stitching on the smooth (no bumps) headband, and the colored center ring on the driver housing. But this time it is in a deep orange color accent theme, with the twin headband rails, headstrap stitching, inner driver ring, and cable being orange, rather than the electric blue of the K702 Annie. Some people might not like this color scheme, but I think it stands out nicely, if looking somewhat like it was themed after a KTM motorcycle (coincidentally another Austria-based company). The K712 is well made, but it does feel a little more plasticy than something like a Sennheiser HD600 or HD650, and certainly more than a Beyerdynamic DT880 and DT990. 
 
The K712 is made in two different places: formerly Vienna, Austria; and presently, Bratislava, Slovakia. AKG users have bemoaned this now complete abandonment of Austrian manufacturing of AKGs, but with the Slovak-made models, you still have a headphone assembled in the European Union. The Austrian-made models like mine have "Made in Austria" silk screened on the center driver cover, while the Slovak models do not have any country-of-origin markings. While I cannot comment about sound or build quality differences between K712s made east and west of the River Danube, those who may want a potential collector's item should opt for an Austrian-made model. 
 
What it comes with:
 
The K712 Pro comes with two cables: a 3-metre straight cable, and a 3-meter black corded cable for plugging into mixing consoles. Also included is a satin-lined black velour carrying bag, which other K7s do not feature, so you get a little more for your money with the K712. 
 
Comfort: 
 
The K712 Pro features AKG's tried-and-true self-adjusting headband, which features a leather strap suspended by elastic bands. It makes the K712 a highly comfortable headphone, in addition to its moderate weight, but the bad part of this is that the elastic bands will begin to weaken over time and lose their tension. This will cause the headphone and the ear pads to slide down your head over time, and it also means the headphone will not sit firmly on the head. So far as I can tell, the solution to this is either to send the headphone into AKG for an elastic replacement, or perform a DIY fix. 
 
The ear pads on the K712 are thicker than the older K702 Annie pads, but are not as thick as the K701, K702 and Q701 pads, and are not angled. Despite this, the K712 retains its spacious ear cups, with the padding made from dense memory foam that conforms nicely to the shape of your head to form a comfortable seal. If you wear thin-armed glasses, then you should have no problem wearing the K712. My ears are notorious for have a problem with rubbing up against driver covers, or getting irritated from having the backs of pads rub against them. With the K712, neither of these comfort issues are present, especially considering the moderate clamping force, and the pads that do not collapse like Sennheiser HD650 and Beyerdynamic DT880 and 990 pads often do. The earpads also run fairly cool for my ears.
 
Sound:
 
Now this is where we get into the most important distinguishing feature of the K712...
 
As I mentioned earlier, I have not found all of the K7-series headphones to be the most satisfying to listen to. The Q701 was extremely spacious sounding to my ears, but I found its overly left-right-panned soundstage to be unnatural at times with older stereo recordings, causing all of the music to go in either direction, and making the center image go dead. In addition, I hated the upper midrange hump, which caused horns and saxophones to trigger an immediate cringe from me. So I thought the soundstage and glare needed addressing. Next I owned the K702 Annie. The Annie was a significant departure from the Q701, with what sounded like a large amount of dampening added to it. Instead of the overly-panned soundstage, the Annie now sounded closed in and highly intimate, the treble was significantly darkened, and there was a slight boost in the midbass (the Q701 had good bass extension though). But there was still that funky upper midrange bump that still stood out relative to other frequencies, especially since the treble was decreased and the bass was increased. The pads also did not have quite enough depth, causing my ears to touch the drivers. So next I tried the K7XX, which was a Chinese-made 200-dollar K702 Annie, but with deeper earpads, and a more toned-down upper midrange. Unfortunately for some reason, this combination managed to end up soundnig dull and lifeless, which spoiled that AKG magic. So finally I tried the K712. 
 
To my ears, the K712 combines a mix between the K702 Annie and the regular K702 or Q701. The headphone overall has an unstressed, fairly musical sound with an overall even tone, and a slight emphasis on the upper midrange and treble. There still is that upper midrange peak at around 1-2,000 Hz, but this time it meshes better with other frequencies since the bass and treble are more even with one another, so the balance ends up sounding less harsh and more neutral, while allowing that presence region boost to contribute to a more musical and engaging sound. The K712 still has that upper midrange increase but just a better tuning of it. Soundstage is great for a headphone of its type, and is the most evenly balanced of any K7 model. It does not pan excessively to the left and right like a K701, K702 or Q701, and it does not sound compressed like a K702 Annie can sound. It has plenty of depth, while imaging and placing instruments accurately. It will not sound out of your head like a Sennheiser HD800, AKG K812, or Sony MDR-MA900 will, but it has better imaging than a Sennheiser HD650, which while being deep sounding can sound blobby with the placement of instruments, and often sounds like a HD600 with simply more depth added. 
 
Treble:
 
The treble on the K712 rarely gets harsh, but could possibly sound sibilant with excessively treble-heavy music (even an HD650 can sound sibilant in the right scenario). There is air in the treble, but overall it sounds mostly neutral. In comparison, the K712 is brighter than an HD650 but much less bright than a Beyer DT990. The K712 sounds great with jazz, acoustic and classical, since the treble has smooth presentation, and contributes to good instrument placement. 
 
Midrange:
 
The Midrange is where the K712 gets into its stride. The midrange has plenty of detail, and rarely sounds stressed. The K712 sounds more musical than you would imagine, and it does not have a bright or overly warm tone that distracts the listener from enjoying a realistic-sounding song. The midrange to my ears is about as realistic and even as you are going to get in an open back headphone for 500 dollars or less. It makes the K712 much more enjoyable than the Q701, which can be irritating, and the K7XX, which can be overly dull. 
 
The bass on the K712 Pro is as neutral as it is going to get on a K7. There is plenty of extension down low, with excellent tightness and a clean tone that makes it easy to distinguish notes. In comparison to the HD650 the bass on the K712 is much less warm, and has a tighter sound, with often better extension. The HD650, especially when underamplified, can overly warm in the bass, and that bass tends to contribute to a pleasing and euphonic sound, but at times can get in the way of hearing finer details. While the K712 has a neutral to somewhat leaner physical bass impact at times, with a good amplifier and a good DAC, it can take an EQ boost, and you can get some good performance with bassy music. That said, the K712 only becomes bassy if the sound it is playing is highly bassy; it does not introduce a bass boost if it does not need to. 
 
K712 Pro vs. K702 Annie
 
Now just to clarify this, the K712 is NOT a rebranded K702 Annie. The two headphones sound noticeably different, though I have heard some newer Annies have been retuned to more closely resemble the K712 sound. Compared to the original Annie, the K712 sounds more spacious in the soundstage, a tiny bit lighter in the bass, and more lively with a more present treble and a more proportionally-balanced upper midrange. To my ears the K712 is better balanced than the K702 Annie, and less dark. 
 
Amplification:
 
First off, do not expect the K712 to sound great plugged directly into an iPhone, iPad or iPod Touch, because it will not. You are going to need to budget in a good amplifier and DAC if you want to enjoy the most this headphone has to offer.
 
The K712 tends to exhibit the same characteristics that are present on other K7s when it comes to amplification: harsh and thin sounding when underpowered or driven on a bright amplifier, dull when not driven on the right source, and revealing of cheap quality DACs. The K712 has a tendency to be less forgiving with poor amp/DAC matches, and often sounds like what you plug it into-to an extent. 
 
I have driven the K712 on the Schiit Audio Lyr 2 hybrid tube/solid state headphone amplifier, and the pairing produces good results, with a tight and unstressed sound, though the stock tubes are a little dull. The Schiit Modi tends to not be a very good source DAC with the K712, as it often sucks a ton of bass impact out of most headphones, and sounds compressed, so I would look at a better quality DAC, or one with a better sound, like an HRT Music Streamer, or Meridian Audio Director. A good sounding and detailed DAC is crucial to the K712, so make sure not to overlook that requirement. 
 
I have heard of people running the K712 off of OTL tube amps like a Darkvoice 336SE, and achieving pleasing results, but do keep in mind that an OTL amp like the Darkvoice or Bottlehead Crack is not going to be the best for impedance matching, as the K712 has a fairly low impedance of 62 ohms, and that impedance tends to stay dead even throughout the frequency spectrum, unlike the Sennheiser HD650. So either a hybrid amp like the Schiit Vali 2, Lyr 2 or Mjolnir 2, or an OTC amp like the Woo Audio WA6 or WA7 would likely be the better option if you choose to run the K712 on a tube-based system. Solid state amps are an excellent choice with their lower distortion figures, lower noice floor and lower output impedance than most tube amps. 
 
As for being driven on a 2-in-1 portable DAC and amp unit, I have been experimenting with both the new Oppo Digital HA-2SE, and the famed Chord Electronics Mojo, costing USD $300 and $600, respectively.
 
The HA2-SE uses the newer ESS Sabre ES9028Q2M DAC chip, which Oppo claims provides a quieter noise floor than the previous Sabre chip in the HA-2. While I do not have the two to compare, I can say that the HA2-SE makes for a very good pairing with the K712 Pro, extracting a good amount of detail, while driving the K712 loud and maintaining a tight and spacious sound. Some people do not like Sabre-based DACs because of their harshness in the upper midrange and lower treble, known as the "Sabre Glare". I do notice some Sabre Glare on the HA2-SE but it does not prove to be a deal breaker, though this glare does not always bode well with the upper midrange emphasis on the K712, and can make the K712 occasionally shouty or blare sometimes. This does not dissuade me from recommending the K712 with the HA-2SE. They make for a pairing that is a great deal enjoyable, and the bass boost switch on the Oppo can add a nice rumble to the K712 when your music calls for it. 
 
But the winner so far is the Chord Mojo. The Chord Mojo is twice the price of the HA2-SE, but handles the K712 excellently, and it should. There is no lack of power and performance, and while the Mojo does not necessarily sound quite as spacious as the HA2-SE on the K712, it makes the headphone sound less stressed and more effortless, with more detailed bass and better imaging, and a less bright tone. That said, the Mojo is considerably more expensive than a K712, so if you cannot justify purchasing it, I can absolutely recommend the K712 with the HA2-SE. 
 
That concludes my review of the K712. Thank you for reading this lengthy writeup, and if you are in the 300-500 dollar market for a neutral open back headphone, and are willing to give an AKG a try, I can safely recommend the K712 Pro. If you like transparent and neutral-sounding headphones, and want a lighter-feeling headphone with more soundstage than an HD600, and a less metallic sound than a DT880 or DT990, then I do not think you will go wrong with the AKG K712 Pro.

6-7 hour impressions. I will update/edit this more as I listen to it more. If you don't like this please GET OUT!!!.
 
These are only impressions vs the bass port modded Q701.
 

1. Slightly fuller sounding in the mids than the Q701m. Barely audible. K712 adds some slight warmth to recordings that are already warm. The Q701m does this less.
2. K712 to me sounds slightly more forward in nature than the Q701m, especially in the low mids. The Q701 low mids are leaner but still nice and full without being too forward.
3. The soundstage of the Q701m is slightly more open/spacious/airy. The K712 is still really very good in this area. On warm recordings the soundstage is noticeably worse. Try the Buena Vista Social Club. That sounds best on the Q701m. The K712 Pro sort of feels like it gives it a slight haze over the sound of that album.
4. The K712 really doesn't sound any smoother or forgiving. There's music that is harsh on the Q701 and other music that's harsh on the K712. Harsh/bright Jpop seems slightly worse on the K712 to my ears due to the more closed in soundstage. This is all random though. Sometimes the Q701 spaces out vocals more so they sound less forward (due to recording). No dang fixing of my poor tracks on either of them.
5. I don't notice any increased bass over the MODDED Q701. I know this will surprise some people. There may be a little, but not worth pointing out. The low bass is still not perfect. I remember the Annie having a little more perhaps, but that's based on memory. The idea of ruler flat low bass to 10hz is good for a laugh! No way! Both sound like they have some slight roll-off still.
6. Both are very very accurate to my ears. None of my music is dramatically altered. Isn't that how it should be?
7. Both headphones are able to reproduce male/female vocals that sound way too distant or way too forward. This seems to confuse some people. Female vocals don't really sound all that much more forward on the Q701. It doesn't magically shove them forward despite what some think. Both have good soundstage depth.
8. The K712 doesn't sound even remotely dark to me. Perhaps a little less treble than the Q701, but again not very audible.
9. Level of detail is about the same. K712 doesn't sound any more revealing.
10. Some music sounds noticeably clearer on the K712, but this is very rare. Maybe if I had ALL HD tracks this would be easier to spot.
11. Modded Q701 sounds very very very slightly more neutral to my ears. Mostly due to it's flatter low mids.
12. In 6-7 hours zero fatigue or discomfort. Nice!
13. I disliked the Annie but love the K712 Pro. No clue why, but I think I was right and it's the improved pads. That's my only idea.
14. I could not really detect any difference between my DACs with the K712 or Q701m. Sound transparent to me.
15. The full low mids of the K712 are really addicting. My brain tells me the K712 is smoother in the low mids, but I think it's fooled due to the warmer sound. Makes sense.
16. Vocals sound a bit fuller on the K712 at times, but not by much. It's VERY subtle. Don't know why but they remind me a little of the HD-598.
17. To me it sounds like a perfect mix of the K702 and HD-650.
18. After dozens and dozens of tracks I did find a couple tracks that sounded easier on the ears with the K712. ONLY some 128kbps bright/tinny/harsh tracks from a singer named "Hitomi". I guess perhaps the K712 is more forgiving of low bit-rate files? I have very few of them. This makes sense to me. I really can't call it a forgiving headphone. Who uses 128kbps mp3 files anyway with such a headphone?

 
RESULT:
 
Both headphones sound great! I highly recommended both.
 
Final overall sound score (mid-fi):
 
Modded Q701: 9.75/10
K712 Pro: 9.75/10
 
For reference:
 
Q701 stock: 9
HD-650: 8.75
Annie: 7
K601: 8
 
I would be happy with either headphone. Due to preferences I prefer the modded Q701 slightly despite no change in score.
 
If you don't like mods or prefer no bumps, I can definitely suggest the K712 Pro.
 
To me you can't really say which is better. All depends on preferences.
 
I have to get this out of the way but there was not more than a 5% difference between the two. Think i'm wrong? Get a modded Q701 and compare them and report back.
 
If AKG can afford to get these down to $325 they'd be a pretty good deal. $400 is kind of high.
 
Disclaimer: My Q701 might be darker/warmer or bassier than the rest. I really don't know.
 
NOTE: My gear has about zero warmth itself that's audible by me.
 
Good job AKG!
 
EDIT: I know they say the K702 and Q701 drivers are the same, but I don't know. I have my doubts. Most likely the K712 Pro uses the best measuring K702 drivers (with different part #). So K712 would possibly equal hand selected K702 drivers + memory foam pads and flat headband. The extras are not exactly free. $350 is a fair deal. When I listened to the K712 Pro with Q701/K702 pads it sounded closer to a K702 than a Q701. I did not install the Q701 outer grill and foam though.

First quick impression, without longer burning in time - a little bit more deep bass as Q701 with:
Mystical Scent, Magic of Mimalayas, track 01 Sacred Book - and other tracks of this XRCD
http://www.jpc.de/jpcng/poprock/detail/-/art/Yun-Tian-He-Mystical-Scent/hnum/4281185

More please see here
http://www.head-fi.org/t/659251/akg-k712-pro-announced/375
http://www.head-fi.org/t/659251/akg-k712-pro-announced/390
http://www.head-fi.org/t/659251/akg-k712-pro-announced/405





Update:

My short Conclusio frist - at the moment the K712 is the AKG flaggshif (K702-65 anni are limited and K1000 is obsolete).
The bass is the best of all AKGs headphones I ever heared. Over all the K712 comes very close to the D7000, so I cannot say who is better, they are different.
.......

The K712 is hand-crafted in Vienna (Austria), pre-selected transducers, 3 dB improved low end performance, soft genuine leather headband, open back dynamic headphones, sensitivy 105dB/V, 10 Hz - 39.800 Hz, 62 Ohms, max. input power 200 mW, cable 3m 99.9% OFC (from the cover).
Enclosed accessories: Additional coiled cable, black velvet lookig carring bag, adapter 1/8" to 1/4".

The Pads of the K712 are not angled as the pads of K701, Q701, K702. I have no K702 Anni, so I could not compair them.
.......

The K712 brings this passage a bit more powerful and (if I do anything wrong imagining) an a little bit closer to me. The Q701 (with original pads) sometimes seems in direct comparison a little bit "thinner".

The Planets op.32 / Montreal SO, Dutoit / Decca, DDD, 86 / Tr. 1 - Mars
https://www.jpc.de/jpcng/classic/detail/-/art/Gustav-Holst-1874-1934-The-Planets-op-32/hnum/5131961
K712 more of blackness, massive, trumpet horns aggressive than the Q701

Misa Criolla, Josè Carreras, Philips, Tr. 1 & 2
K712 punchier in the bass, drums show more body, the voice of José Carreras hardly shows a marked and reproducible change.

And prevent it from being so one-sided for some POP fans

Steve Vai, Sound Theories Vol I & II
https://www.jpc.de/jpcng/poprock/detail/-/art/Steve-Vai-Sound-Theories-I-II/hnum/9825226
Here, the K712 can finally show what it can do - there's so right from the post that rips!
(translate from german: da geht so richtig die Post ab, das fetzt!)

The K712 seems to be for rock & pop fans a "must have"!
The AKG K712 is of the headphones I've heard so far, been the most pressure coupled with the openness of the 7xx series.
Since no K550, K271 MKII come with - even if you gently rotate hearing something quieter (you should no longer constantly exaggerate).

Le Sacre du Printemps, Igor Strawinsky (1882–1971), Simon Bolivar Youth Orchestra of Venezuela, Gustavo Dudamel
https://www.jpc.de/jpcng/classic/detail/-/art/Igor-Strawinsky-1882-1971-Le-Sacre-du-Printemps/hnum/7589152
Massive deep drumbeats (a step in direction to D7000, but not over-emphasized), horns sometimes aggressive (as they should be).
Spatial broad.

Amber Rubarth: Sessions From The 17th Ward
https://www.jpc.de/jpcng/poprock/detail/-/art/Amber-Rubarth-Sessions-From-The-17th-Ward/hnum/2952935
Dry drum beats heavy, Chello corporeal, percussion - the sometimes very hard knocks are very well reproduced.
Wide-ranging spatially staggered singer at "eye level".

One of my Milestone Test CD's now inserted "Quincy Jones Back On The Block" (Tr. 1 & 2 prologues Back on the block) and turned up a track louder. Punchy and deep - and that really thrilled!

Misa Criolla, Mercedes Sosa, DECCA
The deep pounding of Indian percussion instruments comes across very authentic. Mercedes Sosa's voice sounds very full-bodied.
Stage fanned wide.

Roger Waters, Amused to Death (Tracks 1,3,4,5,7,8,11,12,13,14)
K712 a trace fuller as Q701, more bass, despite the same sensitivity of 105 dB / V seems a tiny lane louder (because the sensitivity at 1 kHz is measured, a consequence of the enhanced bass range), basin (brass) metallic silky

......

Now after a burning in period about 90 hours, I play'd my mostfull bassheavy music I have (big asian drums - with D7000 blows air between pads and ears trough) - Yun-Tian He, Mystical Scent
http://www.jpc.de/jpcng/poprock/detail/-/art/Yun-Tian-He-Mystical-Scent/hnum/4281185
track 1 and 9
with K712 the drums seems a bit bigger, deeper, powerful, punchy as with Q701
mids an highs seems me very similar to the Q701.

Before this CD I heared "Bettina Wegner, Die Liebeslieder" - at this music this extended bass is hearable, but hard to detect.
Mids an highs seems me very similar to the Q701. With K712 (and this music) sometimes I have the feeeling a little bit more detailed but in cross check are not surely detectable - my imagination?

The specified AKG increase in the low bass of +3 dB should be real available. Unfortunately I do not have measuring equipment to be able to measure the exact.

.......

compairing K712 with Q701 (using the K712 pads)

The K712 have a bit more (fuller) bass as my Q701 with the pads from the K712 - but its very hard to catch, the music sample must be right.

The K712 plays the "creaking" ("knarzen" in german) of the chello a little but more succinctly as the Q701 (with both implementations of pads tested).

These differences are very small - I will test them on an other day again to confirm my own impression.

My used test samples for this: "AUDIOphile Pearls Volume 1" http://www.musik-sammler.de/media/817284

.......

Meyer Records Vol. 1
http://www.jpc.de/jpcng/poprock/detail/-/art/Meyer-Records-Vol-1/hnum/7495951
Compareing K712 <--> Q701 (with K712 Pads)
K712 - bass is a bit deeper, a bit more resolved, free.

In the long time test (I heard quite a few of my CDs "up and down" in the meantime) the K712 revealed a fatigue-free listening. All images were played back in great detail. The bass seems "the right place" and is not bloated (what with the D7000 occasionally occurs).
The K712 affords no noticeable weaknesses. Otherwise error in the images are very probably noticeably - yes finally, that must be the meaning of Studio Headphones (the main purpose of the K712 Pro).

Roger Waters, Amused To Death, Tr. 12 "Three Wishes"
http://www.jpc.de/jpcng/poprock/detail/-/art/Roger-Waters-Amused-To-Death/hnum/1594911
K712 vs. Q701 with flat (K712 like) Pads
The hiss of the basin (brass) appears a bit more terse and a bit better resolved with the K712.
The deep roar of the Three Wishes comes with a bit more pressure at the K712.

In my compareson tests, mostly I play short sequences of a few bars again alternating with the two headphones.
For me the K712 ranks about the Q701 (both - original or K712 pads).

PS: You must seen all my test are subjektiv - for your own opinion you should compare this headphones self.
Less subjetive tests are ABX blind-tests with more persons - but this are hard to do with headphones.

some links to my head-fi posts
http://www.head-fi.org/t/659251/akg-k712-pro-announced/405#post_9501889
http://www.head-fi.org/t/659251/akg-k712-pro-announced/435#post_9505971
http://www.head-fi.org/t/659251/akg-k712-pro-announced/450#post_9508694
http://www.head-fi.org/t/659251/akg-k712-pro-announced/495#post_9522281
http://www.head-fi.org/t/659251/the-akg-k712-pro-support-and-appreciation-thread/720#post_9554567
http://www.head-fi.org/t/659251/the-akg-k712-pro-support-and-appreciation-thread/795#post_9568028
http://www.head-fi.org/t/659251/the-akg-k712-pro-support-and-appreciation-thread/810#post_9601186

Not quite a review but thought I'd quote my recent observations.
 
Quote:

rob80b said:

  Well the K712s showed up, just doing some preliminary comparison with my K701s with the bass port mod. Won’t see what they’re really up to as I’m currently in my shop with an Imac running uncompressed iTunes into a 25-year-old Technics receiver.
Except for the color, black vs white, physically they look more or less the same, different leather head band and pads of coarse.
So what’s up, well I felt my HD700s took a step toward the AKGs (a good thing) and so far these 712s have taken on somewhat of a Sennheiser flavor, being warmer, less airy, less tinny (nasal) than the K701s.
The higher shriller notes that Feist reaches on  “The Reminder” were almost painful on the 701s but passed almost unnoticed on the 712s coming across smooth and very well controlled, nice. But with less air the 712s lose some of the almost holographic sounds from the track “The Water”, but overall the 712s come out the winner on this album.
Using the opening bass notes from Massive Attack’s “Angel” (appears to be the litmus test for bass) showed that the bass port mod on the K701s may have added some reinforcement in the upper bass but the K712s win hands downs with regards to fullness and extension, no contest.
Went on to listening to Kraftwerks “The Mix” and never returned to the 701’s, IMHO the K712s for all intents and purposes, disregarding appearances, are a completely different phone…….smoother, warmer, bassier...  obvious as black & white!

 
 
Should be interesting this evening when comparing them to my current favorites, the HD700s on the Bryston gear
Anyway, that's all for now, gotta get some work done.

 

Click to expand...

 

rob80b said:

  Did not get a chance to do some heavy listening comparing the HD700s but immediate observations were quite enlightening.

"Way back when".. on these forums AKG and Sennheiser were more or less diametrically opposed, the K501s and HD580/600s were two flavors of the day, Grado being a third..... the advent of the K701s and HD650s made this opposition even more so.
Not to go into the attributes of each as there’s more than a decade of that on the forums, but here I am today with the Sennheiser HD700s and AKG K712s and damned if these two offerings do not share more similarities than differences, but in a nut shell the AKG now has bass-deep bass and has become much warmer while the 700s have shed the Senn veil and are crisper and clearer.
Appears that both manufactures in their strides to appease the masses have come head to head with similar offerings, at least when it comes to overall sound.
Without critical listening both phones could by many sound the same, but Sennheiser have put a lot of R&D into the HD700s, especially with regards to the head cup/baffle design and the driver integration and IMHO the results are rewarding with regards to staging and image placement, this of course coming from a speaker guy. 

 
AKG pioneered angled placement with the K701s pads (not to mention the K1000s, another kettle of fish), but never could really hear the difference and the cup/baffle design has been used forever with minor modifications and then there are now the new memory foam pads.
The 700s for me also have slightly better attack and decay, snares having a wonderful snap and bass notes are a little tighter and central images are less recessed. But the K712s as I noted earlier are no slouch either, running off the Bryston BHA-1 they are a lot less warm sounding than when I first heard them paired with the 25-30 year old receiver mentioned above, bass was also better controlled as was focus and detail but not quite the linearity of the HD700s.
Without direct comparisons and depending on associated equipment IMHO it would be a coin toss as to which is the better phone.
There are differences but they’re close so I’m sort of torn if I’ll keep both, the biggest deterrent for the K712s is the 3 pin XLR as I much prefer the added 6dB gain using balanced as single ended, depending on source, the volume control can get maxed out on the Bryston BHA-1.
The K712s need major surgery for the conversion, unlike my K701s, K501s and DF240s, although I’ve spent a special request to AKG service to if one can get the left cover “without” the mini xlr socket installed and either install a 4 pin mini XLR or even better…hard wired.

Click to expand...

rob80b said:

  Bit more observations while in the thick of things.
 
How much bass do they guys have, well I did mention previously that I’m a speaker guy, right, (not solely though

) so I do compare my phones output periodically to them. Doing just that while listening to Underworld’s dubnobasswithmyheadman the K712s had more apparent bass than my Dynaudio Special 25s  which are augmented with a 15” Velodyne, and it’s dialed in rather flat using Velodyne's SMS-1.
I’d really have to say that the K712s may have too much of a good thing, the Senns HD700s are much flatter and match the speakers/sub output to a T, but without taking an actual reading I would venture to say the AKGs may have a bit of a mid bass bloat.
The HD700s also match my Dynaudio 25s tonally, again the 712s coming across warmer and less defined, the HD700s having better image focus and staging, which I attribute to the Sennheiser’s attention given to designing and integrating the new ear cups, baffle and driver.
Still the K712s are an enjoyable listen and a far cry from my original K501s and K701s and if I hold onto them, probably my go to for movies.

Click to expand...

 
This AKG may win over stuck in the mud Senn hd600/650 stalwarts but alienate previous AKG K7xx lovers, my previous K701s are up for sale.

This is going to be a short review, just letting you know in advance.
I listen to mostly contemporary pop, classic rock, as well as a little classical. In my search for a good headphone to use for all around listening, I stumbled across these, and I must say I'm quite impressed!
For me, the bass is absolutely perfect. Of all the headphone I've heard, these have the best quality bass I've heard. It's not just the quantity, but the control that really sets these apart. It even extends down below 20 khz, barely audible but you can feel it!
Aside from the improved bass performance, it's overall very balanced, but I like to nitpick so I must comment on just one flaw these phones have. In the lower treble, the 2kz has a peak that sounds somewhat unnatural in some recordings. It doesn't bother me that much, but sometimes it makes poorly mastered recordings sound strident and compressed, therefore less "airy" sound. I just EQ it down by 2 decibels, and it sounds almost perfect. 
The treble not sibilant at all, and it's very detailed yet not fatiguing to listen to. I've read that some people think there's not enough mids, but that's only an illusion created by that 2 khz peak, it has very good mids. 
Overall, very solid headphones for the price, other competing headphone such as the Beyerdynamic DT 880 and Sennheiser HD 600 will have a tough time beating it.

One headphone for all people? I think the K712 tries very hard to please everyone and in doing this misses the boat in focusing on being the best at any one thing. Great headphones but it's not that simple! Well built but delicate. Much better pricing through Amazon than the $699 MSRP but unless you already own a suitable amplifier you are probably going to end up budgeting for one of those too. With tons of competition between $150 and the $700 MSRP it's actual value comes into question, especially when some of their biggest competition bears the name of the same manufacturer. They have a big sound stage, but not the biggest. They have extended bass, but aren't really for bassheads. They are detailed and analytical, great for critical listening, but not as good at this as even some of their older models. They are fairly neutral but are they actually a serious solution for the sound professional? Who are these really made for?

K712 vs memories of K701:

These are the first AKG K7 series I've heard in something like four years, after I sold my K701, mostly because the *bumped* headband caused me discomfort. The K712 is FAR more comfortable, on my decidedly large head. From memory (on the same amp, source and music) it seems like the K701 was brighter, perhaps more "neutral", whatever that means. The K712 certainly do NOT want for bass! By contrast my memory of the K701 was a lighter on the bottom end, more forward in the mids and perhaps more "bright" on top which in particular made them a very revealing listening experience. I remember a good portion of music sounded so bad on them (compared to the stuff that sounded SUPERB) that I didn't even want to hear certain songs on the K701. Every recording and mastering error was revealed. The K712 seems more "forgiving" of bad quality recordings for some reason. I also remember the K701 having a more spacious sound stage but perhaps that's just because I've been listening to M50s in their absence...

K712 vs ATH-M50:

To my ears the biggest difference between the K712 I just got and the M50 I've been listening to for quite some time is the obvious trait of whether or not one is closed or open backed. Historically its often that fans of the competition like to say the AKG open backed cans lack bass. AKG paid attention and first released the Q701 (which I have not heard) that was said to have improved the bottom end and now the K712, which have bass in spades! The M50 by comparison is often noted as having a LOT of bass, often trading blows with cans like the Beats... and winning. I found the K712 was VERY close to the M50 in the bottom region. The K712 also definitely sounds bigger, more spacious, more "speaker like", than the M50.

The K712 is more resolving, more detailed than the M50. At first, when I was really listening close for any obvious sonic flaws I kept catching things that made me think one or possibly both drivers were somehow messed up. I'd throw the M50s on and listen to the segment in question again and sure enough, there it was. The M50s showed it too but seemed like it just wasn't as obvious. This happened on songs I thought I knew pretty well, too! At one point I heard a sound in the rear of the left stage that made me think my 18 year old son was trying to get my attention (sounded like his quiet baritone.) I took the left cup off and turned around in my chair to see what he wanted... an no one was there! With good recordings the K712 can make things you've never noticed before jump out of the music at you... Almost "hairs standing up on the back of your neck" spooky how this happens. Putting the M50s back on my head and listening very closely, sure enough, there was that sound was again. The M50s produced the same sound but it was so awash in the rest of the audio that I had just never noticed it before. The M50 is a great, capable, pair of headphones. They don't resolve details quite as well as the K712, nor do they have the same sort of spacious sound stage (no closed back can I've ever heard are any different in this regard) but... they are less than half the price of the K712! This shouldn't be interpreted as a deficiency in the K712 but rather a testament of just how good the M50 IS. It's what I consider "the point of diminishing returns". The K712 DOES sound better, to my ears, but you pay twice as much and do not, arguably, receive twice the value.

COMFORT:

Comfort, since my masochistic love/hate relationship with the bumpy K701 a few years ago, is now the top of my list to check off when buying headphones.  A pair of cans you seldom use, no matter how good the SQ, are the worst ones of all!  The K712 is very comfortable from the smooth headband to the velour covered memory foam ear pads.  The clamping force, if anything, might actually be on the "too light" end of things.  They haven't fallen off my head yet but lots of head movement as a test will reveal these slide around a bit more than most will find ideal.  

BUILD QUALITY:

Bitter sweet trade offs. Far more comfortable than the K701 I used to have. No more bumps on the headband! The "memory foam", velour covered ear pads are super comfy too... BUT take very good care of them! AKG wants almost $50... EACH... to sell you replacements! The K712 is one of the largest earphones I've ever tried. HUGE ear cups help produce it's outstanding sound stage and fidelity. And yet these are extremely light as well. But that also means there isn't a whole lot of metal in them. All in all these feel exquisitely "delicate", like a beautiful hummingbird or dragonfly. I wouldn't want to sit on them. The velour bag that is included is a nice thought but really, for these cans I'd much rather have a solid hard case to put them in when I'm traveling. Not exactly flimsy but "built like a tank" (or a pair of M50) does not come to mind.

SOUND QUALITY:

Like it's relatives the K712 thrives on current and voltage stability. Yes, you can plug them into an iphone or the headphone jack on your computer or something but to really hear them at their best will require a good quality amplifier, the more powerful the better. The K712 is a highly dynamic headphone, sound reproduction wise, and can go from revealing the softest, quietest subtleties to thunderous drum crashes instantly, without sounding strained, but it takes a well built amplifier that will provide plenty of headroom to really make it happen. But given what it thirsts for these are a real treat with just about any music. They are full of bass, nice mids and detailed highs... But do none of these things extraordinarily well! I think I would trade some of this "improved bass" for a slightly more analytical presentation in the mids and treble, like I remember the K701 as having. That said I perceive no weakness in their sound either. Nothing too bright, too boomy, too "fatiguing".

Some critics of the older models liked to claim that these are only good for classical or possibly acoustic jazz. I never felt that way about my K701 and with the K712 it becomes a meaningless point for debate. Vivaldi, Eminem, Rammstein, Kroke, Benny Bailey, Shpongle, Pink Floyd, Dianna Krall and Three Dog Night all sound excellent on these 'phones. I listen to a wide range of musical genres and I have yet to sample any of them that made me think these weren't excellent headphones for that particular flavor of music.

VALUE:

Replaceable ear pads, even at a bit of a premium price, nice. Replaceable cables are a nice feature that any headphone over $200 should have. The K712 includes two cables, one straight and one coiled, and both are just the right lengths for practical use. Well machined, gold plated screw-on adapter from going to the gold plated 1/8" plug to the larger 1/4" size. Velour travel bag? Does anyone really put a $700 pair of headphones in a fancy pillow case? AKG could have kept that and lowered the price another $20 or something.

With an MSRP of $699 I think AKG was very brazen in the market it wanted to challenge. Not that I've heard any $700 headphones but for THAT kind of money I think they had better leave zero room for complaints. The K712 aren't that. At Amazon's price around $350 I think they become a much more solid contender although some of their stiffest competition also wears the AKG badge. Priced much lower than the K712 perhaps a K702 or Q701 would have fallen a bit more in the middle between the K712 and the K701, sound quality wise, perhaps not quite as much bass and lower mids but slightly more detail and neutrality? Off the cuff I think that if I would have paid anything close to the MSRP for these cans I'd probably be sending them back and buying BOTH the K702 and Q701 just to find out for myself! But at anything close to $350...

This is my first review on this site, so if I make any errors please let me know

Physical
Build: Eh... it's cheap feeling, with plastics everywhere, making it feel flimsy. The leather headband is nice, and the plush earpads feel great, but I can't get over the creaking noises they make when I adjust them. I suspect this is to make them lighter but I do not know.

Comfort: Excellent. The earpads are plush and deep, while the leather headband feels luxurious and comfortable, and doesn't snag my hair. The self-adjusting headband works great and I have no problems with it. The 712s are very light feeling as well, and I catch myself forgetting that I'm wearing them.

Price: I got mine for 80 dollars so lucky me, I guess...

Looks: dimensionally these guys are the same as the 702s and the 701s, but with a different color palette. I love the orange, it is absolutely striking to me and makes the 712s stand out, in a good way. The leather headband is super great looking as well, with orange stitching. Overall I love the looks of these cans.

Auditory
Lets start out with some EQ graphs

Frequency response

Bass

Some rolloff towards the low end, to be expected

Mids


Treble

overall great headphone at its price.

This review will compare between the two semi-flagship headphones from two companies; The K712 headphones from AKG, and the HD700 from Sennheiser.
 
"Expect and discover. The perfection."
-box art from AKG K712's packaging
 
"The HD700 Truly excite your ears."
-quote from cover page of Sennheiser's HD700 manual
 
Along with the first impression, I noticed that the K712 needed more power (the hungry hungry hippo). I had to crank up the volume  about 1.5~2 times for my listening level with Senn's HD700 on my Schiit's Magni 2. I will update the review once I get the Valhalla 2 or Asgard 2.
These I-don't-look-cheap, you know? looking K712 costed me $280, which, honestly, it's a bargain for me. my HD700 costed me $400 though, so keep that in mind. (both are used by someone else for 1-2days without even a scratch on headphones; however, HD700's are more burned in than my K712, my K712 was only used for like ~15 hours, while I used HD700 for at least 8 hours per day since It was next to my bed; that would equal about 200+ hours of use on my HD700.
 
 
Build Quality:
it doesn't look cheaply made unlike the HD700 when compared. HD700 has more of plastic-y feeling, while the K712 has more metalic feeling.
K712 is made in Slovakia, though raw materials are assembled by machines. there is a video of showing how K702's are made in YouTube. If you really need to know how AKG's make headphones, go to YouTube, search video for "How It's Made Headphones"; the video is published by TRR56.
The headbands are elastic, so there is no need for spending 30 seconds of your precious audiophile life trying to perfect the K712 for your head.
 
 
Comfort:
For me, the HD700 won the comfort war. while wearing HD700, my ears doesn't even touch the driver, while the comfy cushions on headband/earpad virtually makes me feel i'm wearing nothing on long term listening. looks I need some proper adjustments with wearing K712s, for the drivers (or the earpad) to not touch my ears. headband itself is elastic, so for the most users, headband will automatically stretched for size of your head.
HD700 wins by a little.
 
Design:
I mean, who would care since you normally wear these at home? It's not like a pigeon would get impressions on your headphones and run into your windows for the beauty.
(I've only seen one idiot pigeon running into windows for plants inside my apartment in South Korea)
 
It would make a difference if you wear headphones outside, though. Personally, for me, I would like to get some decent look since I use my open-backs outside, because my neighbor is quiet.
for design, which is really, a subjective matter; even more subjective than our picky ears. In my opinion, both of the headphones have very aesthetic look; the HD700s have the look that represents like "I listen to reference-class headphones and it even has better look than your Beats by dre", while the K712s give more of.... calmer, not flashy, but not ugly design.
For me, HD700 wins the Project Runway war.
 
Sound Quality
Here's where the distinctiveness that we can see where Sennheiser's sound and AKG's sound.
I can't really decide which would "Win" the Sound war; K712 has balanced sound while the sennheiser have emphasizing treble with bass, giving different "purposes" each other.
The treble on K712 is much relaxed and soft than the HD700's treble everywhere. (the HD700 is infamous of treble spikes noticed by some HD700 users, including myself)
 
Sennheiser's HD700 has forward  bass with even-more emphasized treble that still shows some degree that mids do exist in HD700, though, not dominant.
It gives perfect sense that the HD700 is in middle of HD650 and HD800; HD650's darker, forward mids with lovely bass mixed in with HD800's bright sound with precise imaging with wide soundstage, giving a "who art thou?!" sense of half-blooded child from sennheiser (oh yeah, with more of HD800's silver mesh look).
 
unfortunately, some users found HD700's treble fatiguing due to spikes; many users (such as myself) had to do a modification, known as the anax mod  to the HD700 (originated from HD800), whereby the installed foams around drivers dampen and reduce the emphasis on treble, adding little bit of emphasis on mids and bass instead. 
 
HD700's mids are less present than the K712 because of the dominant bass and treble; but it gives somewhat "immersive" feeling with wide soundstage on my symphonies.
 
K712, however, emphasizes on the clarity with separations of instrument unlike HD700;, while it has emphasized treble and bass, with immersive feeling.
well, it says on the box of K712; "for precision listening, mixing and mastering".
K712 has narrower soundstage than HD700; but it has the sense of realism because of balanced soundstage.
 
On beethoven's 9th symphony (ode to joy, which is also known as the the finale) , both headphones have clear separation of instrument while it really shows distinctiveness of the both companies sound that pursue on.
 
the HD700 gives very immersive sound with bass and treble; with mids that are present, but not really as present as treble and bass. it gives some kind of "live" feeling with the immersive soundstage, further defining the HD700's characteristics, while having full vocals.
 
K712s have different approach; while it has the balanced sound with much softer treble than the HD700, it has much narrower soundstage than HD700. it gave me more of HD650/600 feeling in soundstage; not narrower as HD650/600, but not wider than the HD700. The K712 tries to show the details in the symphony,  while HD700 tries to show the "live" sounding with the wider soundstage. K712s also have the balanced, precise and three-dimensional soundstage, that made me "wow" with the separations of instrument, while having full vocals, but not full as the HD700's vocal (but I wouldn't say K712s have thin vocal).
 
Overall/extras:
The HD700 is more of genre specific (I mentioned this on my HD700 review), it would only show it's true strength on classical music because of the emphasis on treble, unless it is toned down using EQ/mods. K712 is more of balanced, used for many other genres; especially for hearing into details of the music.
I would use both of them for home use, but use HD700 more often for outside use since K712 is just hungry with my Fiio E18 amp+dac; HD700 becomes more balanced if used with E18; losing few emphasis on treble but adding it to mids.