Pros: natural sound, high resolution, great imaging
Cons: unforgiving, sometimes tizzy
Review AKG K812
Ok let me state first English is not my native language, so if a description sounds somewhat weired to you please tell me I would appreciate feedback.
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.