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Best dynamic headphone in production!

A Review On: AKG K812

AKG K812

Rated # 91 in Over-Ear
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Price paid: $1,490.00
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Pros: natural sound, high resolution, great imaging

Cons: unforgiving, sometimes tizzy

Review AKG K812




Regarding the craftship and comfort I can just say: It is really top notch and compares to the world bests favorably. The aluminum parts look very nice and the design is a future classic. They look much better in real than on any photo. The only down side is the cable. While the Lemo connector on the headphone is excellent quality the rest seems to come from a 50€ can. Aftermarket cable maker will make a fortune. There is no chance to use a balanced cable without extensive mods. In short the cable is a shame for the asked price.


The headphone was burnt in with >100h and all comparisons were made after level matching with pink noise.


The focus of this Review will be a comparison to the standard recommendations in the >1000€ (or $) class. The main contenders will be Sennheiser HD800, Hifiman HE-6 (on a great speaker amp like my PASS Aleph J) Audeze LCD2 and my personal reference for a monitoring headphone the STAX SR-X MK3 PRO.


Regarding the reference phones not mentioned in the review I can just state that the Beyerdynamic T1 is clearly beaten. The Audeze LCD3 and TH900 are technically good they are colored while the K812 is a monitor with a flat frequency response and has better detail retrieval. It is even more neutral than any now in production Stax phone except SR-009. The sound has an airiness and resolution that reminds me a lot of my beloved electrostatics.


Even AKG claims, and many users restated it, that the K812 is easy to drive I don't agree. Of course the high sensitivity doesn't call for a lot power. Out of the iPhone, iPod, iPad, Centrance Hifi M8 I had the impression of a too bright can. Nevertheless out of the iPad its sound quality beats all over ears I have heard to date directly from an Apple device. But the K812 sounded much better out of the Bryston BHA-1 and Violectric V200. The soundstage just opened up and the slight sibilance became less.



The K812 is in this area simply world class. It is on par with good electrostatics and a well  driven HE-6. I can not get what Tyll heared here when he stated the the HD800 is is a higher resolving headphone than the K812. In my opinion the K812 wins quite clear.



Well balanced sound over the whole frequency range. It reminds me a lot of my Stax SR-X MK3 PRO and that is the most honest and sometimes even brutal revealing monitor I have ever heared. So AKG has really met the goal of a professional studio monitor. Only the highs are sometimes a bit harsh specially with not optimal recordings.

All instruments on the K812 sound very real and life like.



 More bass quantity and quality than the HD800. The picked bass notes of a contrabass are easily discerned. Nevertheless it is beaten by the bass of the HE-6 and LCD2. They go substantially deeper. Even with the Bryston BHA-1 the K812 the sub 30Hz bass is nearly non existent. And the deep tones of the orthodynamics are firmer and more on the dry side. Maybe this is the result of the measured high distortion in the K812 bass department.



The cleanest mids I have ever heared in a dynamic headphone. The mids are slightly less neutral than on the HE-6 and Stax SR-X MK3. But compared to the K812 the voices on the Hd800, LCD2 or Denon AH-D5000 are kind of too fat. They add a warmth that is not in the recording.



This is the first point for me to criticise.  The super heights >10 KHz are excellent. But the 8. Octave is not done well. It has a 6KHz peak like the HD800 but it is less prominent. And then there is a second peak in the lower treble (3-4 KHz). This might add to the impression of the extreme high resolution in the voice department. The K812 is also slightly sibilant, even more than other bright headphones light HD-800, HE-6 and AH-D5000.

I can get why Tylls' first impression was tizzy. With a little parametric equalization the Problem is easily solved. (-3 dB at 3.5 kHz and 0,3 oct. Bandwidth + -2dB at 6KHz 0,3 oct. Bandwidth) I used Beyonces ingenious 'Single Ladies' for those tests.



The K812 rules this category, it is simply on par with the best I have ever heared. Each instrument and voice has a well defined place and there is plenty of air around it. The only headphone I know of that is better in this is the pricey Stax SR-009.



 The depth is as good as the HD800 but it is much wider with the Sennheiser. Especially with symphonic music is the difference quite big. The Soundstage is  comparable with the HE-6.



The AKG shows clearly any change in the chain feeding it. I have never found a headphone that acts so sensitive to the change of the DAC and amp. Especially bright sources or amps like the Mytec DSD192 or the CEntrance Hifi M8 make the K812 even more sibilant.



The K812 lacks completely this attribute. It is a studio monitor and can sound brutally honest. Friends of the TH900 or LCD2/3 will always miss something with the AKG. Even the HD800 ads a more mellow sound to voices and the very neutral HE-6 sounds more euphonic. 

Recording Quality: The K812 shows merciless any mastering error.


A slight noise floor in the background will be revealed more than with any other phone except my Stax SR-X MK3 pro and that is the most revealing can I ever found until this day. Bad recordings are a torture with the K812.


Now a few comparisons with music samples



Beethoven Symphony 9, Leonard Bernstein, Ode an die Freiheit Like mentioned before I think the HD800 is better for big orchestral music. With the Sennheiser you have the feeling of watching the stage of the Berlin performance from the 4th row while you sit on the stage with the K812. But the tonality of the K812 and HE-6 is better here. The huge resolution of the K812 is really amazing. You can hear many details of the ten thousands in the audience like somebody sneezing another dropping something etc.


Miles Davis, Kind of Blue

I like the soundstage and imaging of the K812 better with this classical album. The smaller and more intimate presentation is more like the original setting (I know this recording nearly by heart with many stereo systems). To hear the slapping of the Bass, Evans piano strumming and Davis pressing of the valves is simply stunning. It is as detailed as the Stax SR-X MK3 pro. Only the sub bass of the LCD2 is quite a bit better and the piano sounds more natural with the HE-6.


Kodo, Heartbeat Drummers of Japan

The LCD2 is a force with this recording. You can nearly physically feel the size of the big drums and that is a quality you don't find on the K812. But all the details of the noises around and the sticks hitting the drum are really impressive. And the imaging is more precise than the HD800. With this album I see a draw between the K812 and my HE-6.                            


Kings of Leon, Mechanical Bull

This was the surprise of the listening session. The AKG was amazing good with this record when compared to the alleged rocker LCD2. The Audeze sounded slow compared to the K812. But the HE-6 made the guitars sounding more real.


Leonard Cohen, The Essential

Cohens voice is my personal standard for how real and lifelike a headphone sounds. Every can presents that rough voice in a different manner. The K812 presented his voice quite nice only the female background vocalists sounded sibilant sometimes. The HD800 makes the voices sounding more beautiful than they are by adding some weight to the 4-5 octave. The K812 is more true to the recording here. Nevertheless the HE-6 stays my favorite.



The K812 is in the sum of its attribute the best dynamic headphone you can buy new at the moment. It is a genre master as long as the recording is good.  He wins on the Bryston BHA-1 even against my beloved HE-6. But on a Pass amp the Hifiman flagship is still another beast and wins by a small margin. And my SR-X MK3 keeps the crown of the most accurate headphone.

I would not recommend the K812 as sole headphone. For bad recordings you would need something more forgiving like an Audeze, Denon D5000/7000, Fostex TH900/600, HE500 or a HD650.


But it is an excellent choice for those looking for a real high resolving can.


Great job, thanks Dan.
Thanks, gave me a good read
Nice to read more reviews about K812 
Some of your impressions likes mine.
My conclusion  - K812 is a very good headphone, but everybody (before buying) must hear them self and make his own adjudication.
Cucera...Can you list the rest of your equipment?
And what exactly is tizzy?
Tizzy is a word Tyll used for the K812 and it describes quite well the feeling i have with it. But I have to add it is not allways there. It has something to do with the high resolution and slight sibliance.

Definition tizzy: state of nervous excitement or agitation. Like in "he got into a tizzy and was talking absolute tosh"

About my rest gear take a look in my profil it is all listed there.
Wow, great read. I probably will never be able to reach Summit-Fi until at least 10 years from now...it makes me jealous to an extent.
Great review, thanks for posting for us.  I'd love to see a review of the K712 also.
Tizzy actually means a lack of control usually. The K812's IR definitely suggests some nonsense going on with the driver (massive aftershock and noise). Essentially, according to the measurements, the K812 sacrifices diaphragm control for speed and tonality.
AKG probably used an extremely thin substrate for the driver, it'd certainly explain the aspects of its sound.
I think it is not so much a lack of control but an extremly powerful magnet (1.5 Tesla) and the fully open built contribute to this impression. But maybe thr higher power of the Bryston BHA1 and Violectric V200 was the reason for the better impression.
...no, tizz is a lack of control, its caused by voice coil wobble and bad modal breakup, and a stupidly thin diaphragm would be susceptible to those things but still explain the stat like detail and air. Magnet strength does absolutely nothing for sound, it only makes the headphone more efficient. 
Oh, and, a current oriented amp (like the BHA-1 an the V200, wouldn't you know it) will improve the control of a headphone, especially a low impedance one like the K812. So yes, that's why they sound better from those amps. However that can only help so much, so don't overstate that too much.
tokato14, where do you got that tech info from?
Various places; a mixture of research, common sense, physics, and experience.
An AES paper would be more convincing, the sound of a headphone is a complex funktion of geometry, diaphragm, magnet...
Um, okay. Think of it this way. A piece of cardstock attached to a tube versus a piece of paper attached to the same tube. Move the tube upwards and downwards and the paper will flex and bend a lot under the weight of the air. The cardstock will move far less, far closer to pistonic motion. The same principle applies to a headphone transducer, the lighter the diaphragm is the more susceptable it is to modal distortion and uncontrolled movement, so the design has to be more capable of compensating for it. The K812 has a small, heavy voice coil and a large, thin diaphragm. That's where the tizz comes from.
As for the experience I mentioned, I'll was thinking of two headphones in particular. The KOSS Pro/4AAA has a big dollop of tizz on the treble. The modern production Pro/4AAAT, which has same driver topoplogy and design, has no tizz at all. The only difference is the diaphragm is coated in titanium, which increases rigidity and prevents modal problems.
Let me clarify something I mentioned earlier as well: magnet shape does affect acoustic properties and thus the sound. Magnet strength does not.
Regarding the amplification tidbit, my friend educated me on that, so I'm not sure where it came from but I know it's trustworthy because he spends hours on researching these things and checking sources to make sure they're legitimate/trustworthy. We're going into the business ourselves later so we're both very well educated on the principles of audio equipment design.
OK I can see where you are going and agree on the membran thing. Good ilustration with your paper.

But regarding the amps I am still quite insecure, because all the amps I used are voltage driven amps and their output impedance is Lower than 2 Ohms and their current abilities should be abundant. Especially the Centrance Hifi M8 and Objectiv 2 should fit the bill. I am an electrical engineer myself (even not dedicated audio developer) and I simply can not explain it.
Low impedance dynamics need a lot of current to keep the diaphragm in check and both the HiFi M8 and O2 are battery powered amps. They simply cannot push that much current, the design prohibits it due to the bottleneck in the power supply. The O2 is a great little amp but it's not designed for high current output, which is why it's not good at powering planars or other low-impedance headphones.
The V200 and BHA-1 are both high current designs, which is why they pair so well with the K812. Its also why the K812 gains sibilance when used with low power gear (like the iPhone). 
Great review of the K812 cucera, thanks!  I also have the SR-009, HD800, LCD-3 and TH900.  The K812 is still not in my favorite shops in NYC, so your review will help in my decision to add to my tool box.
For me, the most important feature of an elite headphone is the soundstage.  If it is too congested with all the instruments and voices cramped near the area above my nose and behind my forehead, then I cannot listen an entire Symphony No 9 without feeling claustrophobic.  SR-009 and HD800 place sources closer to each ear and often project them slightly beyond them. Still, without manipulation like using a Realiser or other software, the effect is still in or near the head.  This, including the feeling of the pads on the ears will never mimic the sensation of being in a live performance.
Both TH900 and LCD-3 does something different when driven loudly than SR-009 and HD800 in that at higher levels, the sensation does mimic a live concert.  The colored bass sends shivers and the tactile feelings of room speakers not just on the face but to a real extent, the entire body.  With tube amplifiers, this experience can be repeatable every time.  The problem I have with LCD-3 and to a lesser degree the TH900 is that around the middle of a symphony, they announce their presence as either the pressure (LCD-3) or temperature (TH900) of the pads decide to say hello.
The HD800 gives more space inside the head for each source, but does it at a softer level.  If you crank up the amplifier, the tactile body sensation from the LCD-3 or TH900 just isn't there for the Sennheiser.
Again cucera, thanks for the effort and I look forwards to a listening to a pair of the K812 real soon.
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