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AKG K612 PRO Reference Studio Headphones


Pros: Well-balanced, natural sound, analytical yet musical, bass deep enough to satisfy and tight. Comfortable.

Cons: Slightly dry sound, needs a strong headphone amplifier.

I came to this headphone after 10 months with a Philips X1. Although the X1 is a good headphone, towards the end of my time with it, I become increasingly dissatisfied with its sound signature.

I stopped listening to music regularly and for a long time I didn't realize that the X1 was to blame! Although every time I used it I would be impressed by its abilities, the sound was ultimately just too bass orientated for me; and also the treble tended towards a glassy tone in some music. So after some research, in steps the K612 Pro. Now this headphone is quite different. Less bass but better proportioned, the sound is more natural with a pleasing delicacy to the sound, particularly the treble, that although a little dry, is open, articulate, never harsh or sibilant and only very slightly rolled off at the top. The mid-band is detailed, expressive and free of any nasty colourations, however the upper mid-band does have a tendency towards the already mentioned dryness of tone, but that's really a minor quibble.


The headphone images very well and keeps various musical strands from merging into each other even in busy,complex mixes. Sound-staging is good but not a particularly strong point of this headphone, it keeps everything at a medium distance; not very deep or wide. However that suits me fine as I find headphones that are very adept at sound-staging somewhat artificial in their representation of the music, not really true to life at all.


The bass on these headphones is just right for me; tight, fairly punchy and ample amounts when called for - okay, perhaps a smidgen more and it would be perfect, but considering this is a £100 ($160) audiophile (or audio enthusiasts, if you prefer) headphone, I'm generally happy with it. Anyway, bass quality is more important to me than bass quantity and the K612 Pro delivers on that front.


In respect of amplification; you'll need a fairly powerful, preferably dedicated, headphone amp. With low power portable devices and laptop headphone outputs you will not get sufficient sound quality or volume. So if you don't have a suitable amp, you should factor in the cost of one if you decide to purchase the K612 Pro.


In respect of comfort; there are no issues at all, not for me anyway. The headphone is very light and the clamping force of the earpieces is fairly gentle, the leather headband sits gently on the head too, and the cushions which are soft and pliant don't cause (me) any irritation.


So summing up, I heartily recommend this headphone. It performs well in all areas and shines in some, such as neutrality and resolution. I doubt you'll find a better headphone in its price range.


Pros: Detailed, transparent, smooth and linear sound, revealing, very natural sound, precise imaging, good sounstage, non-fatiguing, and comfortable.

Cons: A bit finicky to amp, needs a good amount of power, and pads take a few weeks to break in.

This is a brief review of the K612 Pro, to my ears it's my favorite and the best headphone under $200. I'm using a Hifiman EF2A as an amp and an ASUS Xonar DX as a DAC.


Build Quality: The K612 is a well-made headphone and feels solid in my hands. Only gripe is the cable isn't detachable but it's not really something I'm worried about as the cable quality is good and I take good care of my headphones.


Comfort: This headphone was comfortable from the beginning to me but the stiff pads did bother me after a bit. A few weeks of use and the pads soften up and become much more comfortable. I have no complaints about the leather headband, there are no bumps and is plenty big enough to distribute weight well.


Amplification: This headphone must be amped and have good synergy for it to reach it's full potential. If it's underamped it may clip a bit in the sound and sounds lifeless, dull, and flat sounding. People buying this headphone need to go in knowing it needs to be amped. It seems to respond the best to warmer sounding systems.


Soundstage: I personally find the soundstage on the large side on this headphone, while it's not huge, it's not really what I call medium sized either, just simply large. The soundstage has good width and the depth and height aren't bad either.


Imaging: The imaging of this headphone is very accurate and precise, this headphone excels imaging. You have a very good idea where the instruments are located and there is good separation.


Bass: Bass when the headphone has good synergy is very textured and detailed, extends unusually deep for an open headphone and has a large and powerful presence with plenty of impact.


Midrange: The midrange on this headphone is what some may consider forward, it's delicate, precise, has good dynamics, and just sounds very natural and organic. It's just beautiful sounding.


Treble: This headphone is rather sensitive in terms of it's treble response from system to system. It is detailed and revealing, so flaws of the recording aren't hidden. It's quite accurate but can have sibilance issues with some recordings and systems and some systems the 2-4khz region may be a bit too present which can lead the headphone to sound a bit hard and dry on some systems. It has a good and accurate treble, it is slightly rolled off at the very upper registers and doesn't have a lot of air like some other open-backs but it's not lacking air by any means, it's just not an airy headphone.


Conclusion: The AKG K612 Pro is an excellent value for what you pay and is an excellent headphone for people seeking a neutral and linear response. It's among one of the most neutral I have heard and is a real treat if you are willing to work with it to bring out it's potential. The headphone is rather sensitive and is very transparent for it's price. It's a headphone that needs a good system behind it that synergies well with it.


Pros: Roomy ear cups, smooth, linear, natural sound, non-fatiguing highs, well behaved bass, AKG mids, not hard to amplify

Cons: initial ear pad comfort, picky with DACs, hard wired cable (good quality though), not for bassheads, synergy with systems

I have owned several other AKGs, including the K240s, the K702 65th Anniversaries, the and Q701 Quincy Jones Signatures (basically the same thing as an updated K701/702). The K612s sound-wise lie somewhere between the K240s and the K7-series, while having a unique sound signature of their own. 


Build: Made in Austria, and very close to the K7-series, but not exactly. They feel high quality, but not quite as exquisite. The plastic on the ear cups is of a slightly lesser quality compared to the K7s, but is still good quality nonetheless. The headband is a stitched genuine leather band just like the K7s. The cable is 10 feet and hard wired, so not detachable via a mini XLR jack like on the K240s and K702/Q701/K712, but is good quality. It terminates to a 3.5 mm jack with an included 6.3 mm screw on adapter. 


Comfort: Keep in mind that these are not fully broken in. The K612 is right up there with the the K7s, but WITHOUT the angled ear pads and headband bumps of the K701/K702/Q701, and a harder padding than the memory foam on the K702 Annies and K712. The pads are fairly hard against the head due to the firm padding and the clamping, so will be a bit less comfortable at first. However, when they start to conform to the shape of your head, they become much more comfortable. The pads are deep enough for most people's ears, however I have a point on my left ear, and recently I found that point touches the driver covering, causing irritation. To remedy this, I took off the left pad and removed the foam ring insert. This supposedly changes the sound ever so slightly but I don't really notice. Since removing that foam insert I find the left ear pad much better. As far as I know, the K612 pads are interchangeable with the K7-series ear pads. 


Sound impressions:


Lows: The K612s lie somewhere between the K702s and the K240s, with having more bass than the K7s, but less than the K240s. Both the K240s and K702s have a sub bass roll off, with the K702s having a lean bass overall, and the K240s with a strong upper bass and mid bass. The K612 have a thickish sound to them, but with the bass being surprisingly linear across the board and without any particular hyping of the sub bass, mid bass or upper bass. As a result I find the K612 has a very clean and accurate sound to the bass. Now bassheads might not like this, because for tracks that are mastered to require a boosted bass, the K612s will sound untextured and the bass will end up sounding artificial. However, if the track is mastered to not require a colored bassline, or is natural bass from recorded instruments, the K612 does exceptionally well. Like most other AKGs it likes recorded bass a lot, but unlike the K7s, it still does well with synthetic bass if it is mastered right. The K612s are good headphones for quicker, more transient bass like with progressive trance and liquid funk. The bass right out of the box will not sound right, and will have a dip in the mid bass, so burn in is a must to bring out the bass potential. The timbre of the bass has a sort of acoustic, instrumental or almost "wooden drum" sound to it, which gives it superb transparency for recorded music. if you listen to powerful piano playing like Alicia Keys, the K612 does an excellent portraying a sense of sound of low notes she plays. If you listen to Arabic pop or Bollywood, the K612 does a superb job representing tambourines and tables. Coming from a Sennheiser HD598 or in some cases an HD600, you will find that the K612 doesn't have that speaker-like, slightly synthetic sound to it like they have. Its bass has a very "instrumental" sound to it.


Mids: In one word: linear. They are linear across the board, without being glarey in the upper mid range like the Q701s and K702s are. Because of this, they are very easy to listen to. There is a smooth mid range without being dipped to sound tolerable, like on Beyerdynamic DT990s. I have absolutely no complaints with the K612 mids. They are pretty much perfect for me in this regard. They have that characteristic AKG house sound for musicality, so you aren't missing anything there. The mids really don't make any compromises to be easy to listen to. They aren't rolled off, they aren't dipped, and they aren't veiled like with some Sennheisers. 


Treble: These headphones have no particular spike in the treble. It's quite linear across the board, with roll off happening towards the 8-10,000 Hz range. You have to play REALLY badly mastered music for these headphones to sound sibilant. The treble is there, but it isn't forward, harsh or glarey. The K612s are't as dark as the K702 Annies, but are definitely are more forgiving than the K240s, which I find are rolled off in the lower treble but abruptly have a HUGE spike at the sibilance range that makes them piercingly painful with badly mastered music lest I EQ the treble down.


Soundstage: The K612 has improvements to the bass, but there will be inevitable trade offs made. One of these to a minor aspect is the soundstage. The K612s just cannot compete with the soundstage on the K701, K702 and Q701. They do however have a more open soundstage than the K240s. Despite not having as wide as soundstage as the leaner K7s, I do find the K612 soundstage more natural due to not having the tendency to pan extremely left and right with mono recordings, causing the center stage to go dead like the K701/K702/Q701s do. 


Amping: I run the K612s off my Maverick Audio A1 hybrid tube and solid state amplifier and Schiit Audio Modi DAC. I am more than happy with the system, with the K612s taking a liking to the Modi. The K612s also like the FiiO E07K DAC and battery powered amplifier. They don't need as much current as the K7s, and due to being 120 ohms, they can be run off an OTL amp like the Schiit Valhalla. The K612s like the K7s are picky with DACs more than amplifiers; if your DAC is distorting from not being able to handle the equalizer on your computer, the headphones will make this horrendously obvious. So make sure your DAC is up to snuff. The internal DAC on Macs just won't cut it. 


Pros: Bass texture, incredibly smooth across all frequencies

Cons: Treble can be harsh at first; takes time to mellow out

First impressions


When I first tried these headphones out of the box, I was a little disappointed at how the higher frequencies seemed to be more forward than the mids and bass. It wouldn't have been a huge deal, except that the treble was also completely unforgiving on sibilant tracks, which really put me off. The saving grace at the time was that the bass, while not having a huge presence, had a buttery smooth texture that made my mouth water. The clarity and precision of the low end also extended well into the upper midrange, making the k612's perfect for acoustic, classical, and jazz. The overall impression I was left with was somewhat reminiscent of  a more neutral k240 signature with vastly improved separation and detail. 


After three months


Wow. These cans have absolutely blown me away. The treble has settled down completely and now sits perfectly with the bass and mids. The entire spectrum is wonderfully blended without sounding messy or lost, and the imaging seems to have improved as well; the sense of space is more natural and the separation remains consistent without isolating instruments completely from one another. 




Took about a week to break the headband and pads in, though for me nothing about the way these headphones sat was noticeably irritating. Structurally sound, with both metal and plastic parts. The cable is not detachable, which could be a deal-breaker for chronic cable destroyers. 


Pros: Excellent Imaging, Excellent refinement, Great build quality

Cons: 2khz spike, non-detachable cable, not cumfortable with glasses on (may be this is just me)

Build Quality: Excellent.612pro is built like a tank.  Really solid construction with nice professional looking open back headphone. Cable is strong and thick, non detachable cable isn’t a big deal breaker for me.


Comfort: I’d say pretty comfortable after few weeks. Velour pads can be little hard at first, but after few weeks it will become soft. 612pro doesn't have much clamping force, but for me I don’t like using them with my glasses on.


Sound Quality:

First of all I wasn’t a big fan when I first heard the 612pro. I had so many mixed feelings with them when I paired them with Fiio E17, instruments and vocals sounded so distant when I paired them with E17. (update: later I found out it was a grounding issue in my PC. more on this later in the review)


With right synergy 612pro can be a perfect all-rounder, bass goes deep with so much texture, and treble is so detailed without being harsh or sibilant, midrange is great without any recession. I’d say sound signature is pretty neutral. After extended periods of usage I used to appreciate its neutral sound signature, but I found out the treble can be dry, edgy due to the spike in frequency response at around 2khz which is very common with AKGs, so specially some female vocals can be fatiguing, dry due to this, so I believe that's the reason people recommending warmer amps to fix the synergy with AKGs.


612pro is not a basshead can by any means, but for me it suited unbelievably well for dance and other bass heavy genres with so much texture in bass without any boominess , great for instrumental and vocals too, vocals sound so natural with excellent refinement.



Soundstage and Imaging: I’d say soundstage is big but not huge like in MA900. And Imaging is in 1 word I’d say “stellar”, one of the best I've heard despite not having a massive soundstage. 



To me, new AKG 612pro is a perfect all-rounder, under $200 price tag this is the headphone to beat. 





Update with Fiio E17


As I mentioned earlier in my review, I had some mixed feelings with E17 when pairing it with 612pro, but after lots of troubleshooting I found this is not an issue with synergy, pairing with E17, it was a grounding issue in my PC which caused this soundstage issue, which sounded instruments and vocals sound distant and overall degradation in sound quality, first I thought it was some static buildup issue, but after proper grounding, I can confirm E17 works beautifully well with 612pro. so make sure you have proper grounding, but still around the 2khz spike in frequency response was bothering me, I managed to fix that by slightly boosting the bass on E17, that makes 612pro such a wonderfully musical headphone imo. 


Pros: neutral but good impact in the bass, tights bass, price,great for gaming, design.

Cons: it needs a good synergy

this is my first "serious" pair of headphones So the review cant be very full, but I try to give the possible useful information. I was looking for a pair of headphones with a neutral sound but with a good bass impact and suitable for gaming, and i am very satisfied with them.  they do very well with all my music: particularly they are fantastic with black eyed peas and alicia keys ( quality of bass and voices is fantastic !) . i think they do very well with hip hop too, but maybe some song ( for example Eminem marshall mather lp2 ) would benefit from a little more bass (but really very little).. k612 has a very good imaging !! when i play FPS games , the position of enemy are very precise!

however they need a good sinergy .. i tried them on a fiio e10 and on another soundcard of my friend, and k612 was lean in the bass and lack of detail...

but with my EF2A they are special!! more punch in the bass, more details, more clean, bigger stage.

i dont know if it depends by quality or power of amp but they are special with EF2A and they sound more better with a good dac ( dac of matherboard are not suitable) .

very raccomanded !!also for the price : i paied them 135€(shipped) and in the forums they are compared with headphones much more expensive ( sennheiser hd600 for example).

AKG K612 PRO Reference Studio Headphones

(From AKG Website) K612 PRO headphones are reference open, over-ear phones that deliver natural sound imaging for professional monitoring. The advanced open technology offers comfort for long working sessions and a full, spacious sound. AKG’s patented Varimotion™ diaphragm technology completes the unique sound of the K612 PRO. Obvious features such as the self-adjusting real leather headband, aluminum arches and solid rivets not only provide a lightweight, maximum comfort fit, but also reinforce the quality AKG has provided to studio engineers for decades. SPECIFICATIONS: Headphone type: open Frequency band: 12 to 39500 Hz Sensitivity: 101 dB SPL/V Max. Input Power: 200 mW Rated Impedance: 120 Ohms Detachable cable: no Cable Length: 3 m AUDIO INTERFACE Type: Screw-on Jack Combo (1/4" and 1/8") Gender: Male Contacts: 3-pin Interface Finish: Gold DIMENSIONS / WEIGHT Net Weight: 238 g

TitleAKG K612 PRO Reference Studio Headphones
Package Height5.1 inches
Package Length11.7 inches
Package Weight1.7 pounds
Package Width9 inches
UPCList - UPCListElement885038035695
Model Name/TypeMPNEAN/UPC
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