AKG K701 Studio Headphones

These are one of the best headphones I have ever heard, and I have heard a couple. I undoubtedly prefer them to Senn HD650, like them slightly more than Senn HD600 and Beyer DT880. Why? Because they have more natural sounding midrange and airier soundstage, characteristics that fit the music genres I prefer (classical and jazz). In terms of neutrality these are as good as Senn HD800. The bass is nicely extended and precise. Mind you, they need proper amplification. Don't expect them to sound great right out of an iPod. I have heard mine with MF x-can v3 and there is no synergy between the two. A better match is the cheap Pro-ject headphone amp. They sound even better if you drive them with a more powerful amp (ie Burson). I have mine coupled with a Matrix M-Stage V2 and the combination sounds really magnificent. All in all these are one of the best sounding headphones around, and one of the absolutely best values out there today.

The AKG K701s are very good headphones. The information retrieval these headphones show up is very, very good! Vocals are also very good with the K701s in my opinion, and you can hear how good and badly recorded the songs are with the K701s. These AKGs really do show up on things in the music and your set up.

In my opinion, these headphones don't do euphony. They are neutral and revealing!! If you play a song that is badly recorded, these headphones will sound shockingly bad. So be warned!
 

The best phones I've tried so far. I tried some well-burnt-in beyerdynamic and others in similar price range in a store, and I have owned the 601 before.
I also own closed cans, e.g. the K271, and before that, several others further down the price range.
The previously owned 601 was my first open system pair, it took some getting used to coming from cans - but I quicky noticed the advantages especially for certain types of music, e.g. the actually open sound vs. canned.
Sits well on the head due to clever adjustment mechanism.
 
I use these mostly for classical music, jazz, blues, some rock - but only stuff done in good studios by people who know their stuff.
Music with a lot of acoustic instruments (guitar, A-bass, percussion). Some electronic music in the vein of Vangelis or more modern but without boom boom boom can also sound very nice.
This is where these phones shine: Recordings with a lot of details to be heard, especially stereo-wise.
These are the clearest sounding, non-adulterating phones I have had so far. And none have sit so well on my somewhat big head as the K701/2 and 601.
 
Since I've read some funny reviews I can't resist to comment on some things...
Those are *not* phones for:
 
- badly mixed metal / punk albums by half deaf studio "engineers" or / and mixed with low-end gear. Seriously, on some CDs you hear "high" frequency noise that should not be there indicating deaf personnel... yeah, even Dream Theater, not quite a garage band, but it's worse with lesser known bands.
I.e., these phones enable you to hear "everything", and the truth may not be pleasant.
This is not genre snobbery, I own several dozens of metal albums from 80's to prog to death.
 
- some "loads of digital synth & effetcs" music - can be quite harsh at the high end, but this is probably not these phones' fault, but because it's mixed that way
- people who are used to bass-exaggerating phones and albums mixed with low-end gear of the average target audience in mind
 
- mp3 files: may give you ear fatigue quickly, even ones with acceptable bitrate (>=256 fixed) where you can't quite detect artifacts' presence, still quicker fatiguing than original wav. (yah yah, this is an impression, not scientifically tested)
- Internet radio: not only is this often rather low bit rate, but I sometimes have the impression that they send stuff that was converted between different lossy formats, ugh (it's 5 years since I tried to listen to internet radio with the K601 IIRC, though)
 
So, the ear fatigue mentioned by some may well be a problem of their source material.
Of course, these phones, as they are open system and thus not shielding you from external sound sources like closed type on low volume, and the nice sound stage, may tempt you to crank up the volume while not really noticing it is too loud - which will certainly increase the chance of ear fatigue.
There are also people who get that from any headphones (try whether a crossfeed amp helps)
 
And now the obligatory: excuse my clumsy English

Lets start with:
 
Design, build quality & comfort:
 
They are white - thats what people notice on the first look. I must say I really like the design and the "feel" - The leather headband is a nice addition to the white and gray colors.

Build quality is very very good - they are very sturdy and don't feel like breaking apart after a month. I dropped them incidentally few times, rolled with my chair over the cable and they are still in prefect condition. 4 Stars
 
*Comfort - before I bought them I read alot about the comfort (haedband) issue and when I put them first time on my head I was sure that the rumors were true - the bumps were digging a hole in my skull.
BUT: I got them about 2-3 months now and the comfort is no longer a problem for me. About a month ago I tried to soften the bumps by squeezing and pressing them. I'm not sure if it helped, but now I think that they are one of the most comfy headphones I tried! The best are the pads - very thick and deep 4 Stars
The K701 leaks alot to the outside - they could be very annoying to other people. They also don't block much of the outside noises.
 
 
Audio quality:
 
When I put them first time on my head I was simply out of my breath - the amount of details I've never heard was amazing! Vocals also sounds great.
They shows their best when listening jazz, ambient, chillout and classical. Sadly they DO NOT rock. They sound very thin when listening SOAD, Korn or Sepultura:/
 
The BASS issue: the bass is tight, controlled, very deep, the only thing lacking in K701 is bass IMPACT in bass-heavy music and rock/metal.
They've got huuuge soundspace (some say: too big). This is a feature, which makes them great for movies (at least for me).
 
Amping - is another big thema with K701, but DON'T EXPECT NIGHT/DAY DIFFRENCE! - if You don't like them unamped, you'll probably won't like them with powerful amp. When properly amped their sound becomes more smooth and less fatiguing - the bass is also a bit better in all aspects.
 
Burning in - beat me, I'm not noticing any spectacular diffrence over the time.
Overall: 4 and half Stars
 
 
Conclusion:
 
If youre looking for high details, great with jazz, classical (!) and vocals headphones you can't do better at 250$!

I have had these headphones for some time now and would like to write a simple review. They sound absolutely fantastic. I also have a Sennheiser HD 650 which I immensely like for all their virtues but after purchasing k701 I rarely reach for my Senns. k701 is a better allrounder and particularly fits the music styles I love the most, classical and jazz. That big and airy sound is simply magical. Every note and every small detail is so clearly reproduced and presented. The tone is very balanced and quite natural. 

One of the best headphone values out there.

K701 has good performance on sound music, vocal, light music, slow rhythm,  sound track for example. And at the same time, it's easy to broadcast good sound but harder to drive it very well(needs proper equipment--front/AMP/...). But overall, K701 is an excellent Hi-Fi headphone.
 
Good equipment, good pay back

Some have said that these are more suited to classical. I understand why. Personally, I knew I had a keeper after my first session with my Lo Fi blues collection. Hard to admit, but better than my cherished k280. 

I just thought I'd write up a review on these headphones. They did a bit getting used to, because the reproduction of sound is so clear and even. Like getting used to a pair of studio monitors after listening to hifi speakers. These are excellent for mixing, and mastering, and use these to check what I've done with my main Genelec monitors in my studio. I can virtually hear each, even slight turn of a knob, let's say an EQ, or changing the ratio and threshold of a compressor. AKG doesn't offer us hyped up sound, it's all up to the source. I plug these straight into my studio interface. I also don't get the lack of bass, for me, the bass response is flat as it is supposed to be. And I've played bass through zillions of gigs for 15 years!

AKG k701 Headphones A Ten Year Review Retrospective
Review by Redcarmoose 01-14-16

A revolutionary flat wire voice coil optimizes the "coil fill factor," improving efficiency and enhancing HF accuracy

A two-layer diaphragm with AKG's patented Varimotion design virtually eliminates distortion and delivers exceptional imaging.

The diaphragm's thickness varies from 80 µm in the center zone to provide virtually pistonic motion for well-balanced HF response to 40 µm at the perimeter for high elasticity to accommodate the increased excursion required for accurate mid-range and LF reproduction.

A high-performance neodymium magnet structure complements the flat wire voice coil for frequency response of 10 Hz to 39.8 kHz

A 10 ft bi-wired oxygen-free (99.99% OFC) captive copper cable optimizes channel separation and reproduction quality



Manufactured in the past in Austria, now in China.


GENERAL
* Packaged Quantity 
1

* Weight 
8.29 oz

* Color
 white

* Type 
headphones

* Manufacturer 
Harman


HEADPHONES
* Headphones Form Factor 
Circumaural

* Headphones Technology
 dynamic

* Sound Output Mode
 stereo

* Frequency Response
10 Hz
 to 39.8 kHz
* Sensitivity
105 dB/mW

* Impedance
 62 Ohm

* Magnet Material 
neodymium





ACCESSORIES
* Included Accessories
6.3 mm (1/4") stereo adapter






Encapsulated Review:
This is here so you can read a paragraph and move on to another review.

AKG k701 headphones are both loved and hated at Head-Fi. They offer a super big head-stage and do acoustic guitar and vocals in a sublime fashion. They are enjoyed by folks into Classical Music and Opera. They seem to be missing some of the bass energy needed for Pop or Rock. At any extent they are notoriously hard to drive, in consequence many noobs not getting a clue as to what the k701s truly are and what they are not. One key is using amplifier volume to change and control the personality of the individual listening experience. There is no other headphone whose personality can be changed more or altered by select use of specific volume levels in regard to the target mood of the music.

In brief, the personality of this particular headphone is very dependent on chosen volume levels.






A Review AKG k701 Headphones


A Little History:
AKG sold their flagship K1000 headphones starting in 1989. Truly revolutionary, they were actually ear speakers which had movable or (angle adjustable) transducers angled towards the listeners ears at an area a couple inches in front. They offered the complete opposite of headphone cup-color or resonance as you can see by the picture they were just drivers hanging in the air. Their claim to fame is that they just don't have a cup chamber to hold standing sound waves to reverberate and tone the sound response. No solid material to gain and hold sonic resonance or echo. No worry about air port flow or even end weight issues. The K1000s could fully fold which meant that they could be perfectly parallel to your ears or folded out in front. So your speakers (virtual) were in front or at both sides of your ears. The whole idea was to get the sound to become more laid back. The AKG designers were actually trying to get away from the intense aggressive sound of headphones and tried to get relaxed speaker in a room vibe. Still at high volumes our k701s do become aggressive and intense for headphones but mostly due to the treble personality. At lower volumes they can actually start to replicate that laid back feeling of their older brother the K1000s. Funny though most don't really think about how much volume level adjustment effects the personal character of the k701s. They are always providing the same response at different volumes to a point, but the over all effect is completely different. You have an almost ambient room response style at lower volumes and a bright intense listening experience at high volume.


My experience with the K1000s was that they were lightning fast and are able to handle music changes in milliseconds. Another wild thing was for the first time (that I can recall) headphones were now authentically presenting a musical experience as you were in a room facing two forward toed-in loudspeakers. The difference was when you moved your head the speakers moved along too, always keeping you in the sweet spot.

The Novelty Factor:
Hearing the K1000s driven by a powerful amp allows the headphone listener to achieve a unique, almost home speaker headphone experience. The other novelty factor was they were $1200, a bold new price level for non-electrostatic headphones in 1989. Also many buyers found that they needed a new amp too.

I heard them out of a big overpowered tube amp and thought they were interesting but thought they didn't have enough bass for my liking. Still I wish I could have spent a day with them as to spend an hour was not enough time to get a grip on really what they were about.

If folks say the k701s are revealing of source and amp, then the K1000s are revealing to a fault. In fact they are. Every small sonic detail in the recording could be heard along with the complete character of your amp. The drivers were on hinges so you could tilt them different slight directions which would change sound-stage and tone a little. The clue as to why I'm bringing up the AKG K1000s is they are the flagship older brother before our beloved k701s introduced in 2006, exactly 10 years ago. There is an understanding that we would not have the character of the k701s without the first introduction and technology developed for the 1989 K1000s.

If the K1000s were cold, the k701s were warmer, which they actually laughably are to some extent. If the K1000s had very little bass, the k701s had more. Still the k701s are more easy to drive and were introduced with a second generation dual layer driver technology. In short the driver has two materials which allows it to move one way in the center and another way towards the edge area.

Neither headphone keeps the music in as they are both open back with the K1000s being the worlds first fully open front dynamic driver ear-speaker (that I know of).The idea is there is also no cup area between your ears and the driver. Sony has also done some play with this technology as seen in the openness of both some past and current flagship designs.

I was able to spend a solid year with the k701s before finally getting a chance to hear the legendary K1000s . On another level the flagship k701s were much more affordable and remain today as one of the few flagship headphones you can buy for $250. The AKG K1000 retailed for $1200 and they made 12,000 by most estimates here.

I find I like the character of the k701s better. Drums are not so tizzy, and there seems to be a slight generation of cohesiveness obtained by the k701s. Still if your not used to such large sound-stage the k701s can be a bewildering experience on first listen. Due to the open-back design the cymbal splashes and drums end up being way, way outside in the mix. The difference is maybe comparable to seeing a landscape painting on the wall in a home, then seeing a real edge of the mountain landscape. The musical information can be so spread out that it takes a while to get used to understanding it. Remember too, your going to have basically three styles of listeners, one likes closed small sound-stage, one likes middle size, and one loves big sound stages, myself being number three. The entertaining aspect here is that folks who like narrow sound stages will say the open ones are unnatural. The open-folks call the closed sound stage boring and congested. If anything these conceptualizations just go on to show how this headphone business is personal to a fault. Normally the listener and his audio history are the factors which give him or her the clues as to what audio replay is right or wrong. There are rules here, but you know what they say about rules?

Build Quality-Fit And Finish:
So let's start with our construction here. We have small elastic threads or strings which spring load the headband onto our head. Amazingly as the headphones age the springs get worn but for many end up being better when weaker, my experience too. Many have had issues with the bumps on the downward facing area of the headband. Again though with short hair they never bothered me. New models of this style of AKG build have removed the bumps all-together! The headphones only weight 8oz so they are more low-weight than they look. One plus-factor is that we have the cups completely surround the ears with-out touching. For a full-size around ear design I have also found ear comfort to be supreme and one of my most easy to wear headphones.

Do They Last?
They really last as I purchased a pair in 2007 and another backup pair in 2009, both which have held-up without issue. The pads which are a light gray cloth can discolor to a slight yellow with time and extended wear. The ear pads can be removed but I have never tried to wash them with soap and water. If removed there are some models with two pieces of thin foam between the driver and the thin ear cup cloth and another design with only one piece. Taking the foam out and attempting to listen really shows how delicate these elements go to change the overall sound signature, being way too treble like and thin with the foam removed. Overall the cups are made with a hard plastic held together buy large hoop rings which go over your head. The outside area of the cups are completely coated with air-hole panels. There is a solid 16th of an inch thick real leather headband with small "bumps" across the top facing down. I assume the ring wire holds the right signal cord wire as our cord enters the left cup only. There is truly a simplicity of design at work here. Nothing to scratch or bend, nothing to flake-off or change over time.

The cords are non-removable and enter the headphones at the driver side of the left cup. The plug end is a full size gold-plated plug but comes with a mini-jack adapter. Because I use the headphones 100% of the time at home, a full size plug-end is a joy. There have been tales of the newer Harmon made China k701s having a slight squeaky or creaky sound when moving slightly on your head? Both my pairs are early Austria made and don't have that issue. Many members have taken the plunge and gone to take apart their k701s and remove a small piece of tape from inside the driver units which results in a dramatic bass improvement. More on the bass in the sound quality section below. Check out the bass-port modification threads here if interested.

Many have an issue with the white color. I think at the time they did look vary different due to the color and headphone size. They are fairly large headphones despite the great low weight. Much of this cup and transducer size is imperative to getting the sound they achieve. The old saying "They look different because they are different" could not be more true than right here.

A surprise for many is how much small adjustments (up-down or forward and back) of the drivers in relation to your center ear hole can change the sound. I say this because most people never give it a second thought. Most just let the headphones center when put on and fail to experiment with any adjustments after. In whole, the headphones do reach a perfect place with very little fuss, moments after putting them on. The design here is revolutionary in allowing a device to almost fit itself to anyone's head, without the use of an uncomfortable clamping force.

Many believe due to our physical ear and head-shape characteristic, members hear every model of headphone in a different way with a slightly different sound quality response. The headphones really self-adjust every time you put them on with a slight angle of the divers facing slightly back-facing due to a thicker pad in back of your ear. You could also reverse the pads to have the drivers face slightly away and forward, also many members have further covered the front of the driver with felt or more foam, in an attempt to boost the lower mids and bass. Others switch the right and left cables and flip the headphone around to have the thick part of the pads angle the driver away from your ear. All this I guess is an attempt at recoiling from the direct treble response as you find many are not satisfied using EQ as a daily tool to change a headphones sonic signature. Due to the headphones being an open-air style, you never read of anyone attempting to change the non air-tight pad to ear junction with the cloth pads. It seems here that no effect is reached by attempting to change ear pad material. Though it is a good point to note that I have read about slightly different foam used for the ear pads, after studying the k701 history here at Head-Fi. Every variation of the foam is of a harder and non-moving style which also does not seem to compress to a different shape over prolonged time and use. What I'm saying here is the pads just don't wear out or need replacing like you have with many headphones today. The cloth also stays in great shape despite a slight color change.


My review here is fully based on stock units. One pair, an early pair and one pair a latter pair with one less headband bump and the AKG silver button on top rather on bottom. Even though both my two pairs of headphones were made at different times, both pairs sound exactly the same.


The Sound:
If you get a new pair of k701s you may want to burn them in? I seemed to notice a slight increase in bass and bass detail after 200 hours. Some folks think they need 400-700 hours of burn in. When they first came out, you had a lot of reviews calling them pure and flat responding. Now the attitude is they do have a color. This is a character which I feel is just as much from the missing lower bass and lower mid-range.
For many though there is not a headphone in history which sounds like the k701. Some say you have to get used to it, some say the prior is complete nonsense? One thing for sure, they are a different animal than most roaming the fields of Head-Fi.



Maybe the single stand-out AKG trait is the slight mid peak notable on the graph here?

If anything this is maybe what gives our headphones here their unique character?


Viewing a graph of the frequency response is actually a really easy way to understand and confirm what your hearing. They are definitely on the thin side, but at times the speed they react at and the detail combined with the staggering head-stage transcends all of it taking you to an audio nirvana of sorts. Your maybe the most happy by simply choosing your music. Any Vangelis is sublime, any movie soundtrack, Classical and a good portion of Jazz is rendered perfect. On a song like "Come Together" by The Beatles on Abby Road you have a heavy pronounced bass emphasis, and the AKGs actually do the song well. Your never going to think you need more bass for that song, but most other pop or rock songs are going to get to a place where they may sound too thin. Highly thin mastered and brick-walled modern day remasters are going to be shown for what they are. The k701s are an audio microscope revealing the character of each of your pieces of equipment as well as the source material. Still their perfect transparency is going to allow you to hear the vocals in rare form. Giant vocals with effects like you have from Lisa Gerrard from Dead Can Dance are going to be amazing. String instruments like violin washes in soundtracks are both extended far out in the stage as well as detailed and fast to change with no lingering harmonics to get in the way. You have the best of an open back headphone experience. Remember too, other folks in your listening space can also experience the music with open back headphones. They really fail to keep the music in.

Still even with these lists of accolades there is a ball of confusion surrounding the k701s. Many think they sound fake, unreal or plasticky? Many don't enjoy the lack of bass listening to rock music or metal genres. Combine that fact with the realization that few amps can really drive the k701s right. In my humble opinion that seems to be the key to everything here. The sound in relation to amping. Much of this is also dependent on the level of volume desired. So let's start with a sonic artifact of the k701s being amped wrong. They emit a bass response which is surprising to noobs. The bass is there but becomes almost crumbly in texture. The best example of this sound recorded is in the very first part of "Good Times Roll" off The Cars first record released June 6th, 1978. In the first couple of seconds you hear a synth drum introduction but just as the song really begins you hear where they maxed the volume level of the synth drums and they become thin and break apart with distortion. This single recorded tone of the bass seems to be the best recorded sound to try and explain when the k701s are not responding right due to amping. Most of course think their amps are powerful enough and have always had enough power, so it just could not be the amps falt, they wrongly guess? These are just bad headphones they think.

So with the correct signal they scale. They will scale to a point where each instrument has it's own place in the mix. Bells have texture, cymbals have size and decay. Orchestra because it is recorded on large sound stages shows the reality of the recording arena which is giant. ( Maybe the reason Classical lovers like them?) Getting a ton of endless power like from the W5 LE 300b tube amp takes them almost to a perfect place. Folks who recommend solid state like the Schiit Asgard 2 are only getting to 50% of the headphones true potential as a sound transducer and have maybe never heard the k701s out of a powerful tube amp. Hence maybe one of our biggest problems here. Tubes can warm up a little of the sterility here, but most tube amps just don't have the dampening factors or balls to wake the k701s up from their sleep. Best of all though a powerful amp gets rid of all of our bass problems. Gone is any of the crumbly bass with a powerful correct amp. How power hungry are they? Let me put it this way. In truth even a Schiit Asgard 2 is not up to powering them fully. At loud volumes you can get to 80% of full volume before the AKG strut their stuff and start to fail even a Schiit Asgard 2! Yep! They are some of the most power hungry headphones you can buy, period.

Movies:
We have actually had members who purchased the k701s just for movies. When you contemplate what demands movies make for headphones the conclusions become obvious. Movies are dialog and sound effects at times. The k701s do vocals perfect and the ambiance recording is placed in an almost surround sound style. Amazingly the bass in movies gets registered in it's own private area in the mix, complete with detail, texture and color. The speed at which they react to sonic changes and U turns doesn't hurt matters either. The fact that they are nice to wear for long periods helps too. The best part of the movie experience is that our sounds are taking place outside our heads. Place your fingers four inches away from your ears, that is where the action is going on. Some headphones actually place the head-stage inside between your ears, almost like a mono recording. Here we are at the limits of stereo, so movie listeners love them.


Equipment:

Analogue :
I would say the k701s can and do respond well to the slight warm-up a vinyl turntable can affect onto sound signature. We are actually looking to exploit any harmonic complexity found. The vinyl warmth is accentuated in the best of form.

Digital With Tubes:
They also seem to like over-sampling in the DAC department. Again any thing we can feed them with some warm harmonic complexity they are game for. Solid-state is a simple and inexpensive way to power the k701s, though I think something like the Eddie Current Zana Deux S or Woo Audio 5 tube amps really take the AKG k701s to a much better place, overcoming the sterility and warming up the cold they often exude. I would love to find out how they would respond to something like the solid-state Eddie Current Black Widow? There is a chance something like the Black Widow could change the k701s character for the better?

Still, amazingly there are small less powerful portable amps which can just get to the level needed to enjoy the k701s. Listening to Led Zeppelin 24/96 remaster of Stairway To Heaven with the JDS Labs c420 running in non-high-output mode with bass turned to flat. An amp like the c420 can be placed at full volume and with it's output on the cleaner low-level and reach an area of volume at max just enough to work. So getting an uber-powerful amp is not always mandatory but seems to fix much of the trouble areas which come into play trying to get the most out of the k701 headphone.

To sum-up our small review here:
The k701s still offer a value and unique sound ten years later. AKG was purchased by Harman International and had moved manufacturing to China but kept the quality and sound signature the same. AKG has also released many new models of the same basic design improving on bass and middle lower bass response which could possibly make the k701s obsolete in today's market place. The sound signature still offers world class vocals and orchestra renditions and ends up being many a members favorite headphone due to it's abilities and sonic style. At times I feel they are best singing both male and female vocals. Other times their ability to create a convincing orchestra with both tone and spatial clues, is what they are best at?

Getting the amping right is critical to finding this beast's true character and value?
Experimenting with volume is one of the key factors with understanding this special headphone. There is a different musical mood at low volume, just think of the AKG K1000 looking for that laid back sound. Attempting high volumes does work with the right music and amplifier but risks walking that thin narrow line between success and failure in musical emotion.



Cheapest Past Flagship Headphone For Sale Ever
Any money you save may as well get spent on amplification



The Signature Excels At Some Genres
The Headphones Do Movies Perfect With The Right Amplification



Music Recommendations:
First off this is not a normal review where I have only played a couple of albums. In the last nine years I have played 1000s of albums with the k701s. Listed below are just a suggestion of a couple albums which seem to bring out the best in these headphones. They should not be a members single headphone unless they strictly listen to New Age, Classical and Opera music genres.












As with all you ever read at Head-Fi, this is just some stranger's personal results and findings. Your results may vary, you may find you want another sound signature. Headphones are a very personal experience and depend on music genre taste and upstream equipment requirements. Finally your listening volume levels may determine if you like these headphones or not.

Favorite headphone for soundstage and detailed highs

Modified these to balance with silver/gold wiring and Furatec XLR plugs.
After a fairly long burn-in (>100hr) of the cabling and used on the Rudistor RPX-100 dual mono balanced solid state amp these sound very musical and dynamic. Much micro detail comes out and there is a good 3d stage imaging. The sound is very involving and intimate, providing foot-tapping and sometimes goose-bumps. Eargasm?
 
Definitely a step forward compared to the standard non-balanced version which did not impress me much.

Greetings
 
well... how to describe this headphones?...  VERY NICE pair of headphones, very detailed, analitical, good response and bass enough. Very nice on classical and jazz music. Ideal for CDs or Vinyls of symphonic music.
 
Looks very well and need a good amp and DAC, but still unamped sound very nice.

Cheers.

The K701 is not the most perfect headphone, but at this price range it can surely compete with headphones double the price. They certainly need a powerful amplifier to drive them properly. I never appreciated them truly till I used them with the Beta 22 amp and then I found out what I was missing on the lesser amps I used. The best K701 I heard where used around 1000 hours. They sounded very smooth, relaxed and a joy to listen to. They can pick up any weakness in your rig: Source, Cables, Amps. They need careful matching to sound correct. Compared to the K400 which I also own. The K501 has a beautiful midrange which gives a very intimate and special experience, its more enjoyable and more musical, but the K701/2 is more accurate, more detailed with more extension in the highs and lows but sometimes can sound sterile and boring. The K501 lacks the detail and extension of the analytical K701/2 (although they are not lacking in either) but listening to the K501 brings the music to life with a rich tonality which is missing from the K701 with some tracks.  

IMHO - the K701 is one of the best dynamic open headphones of the except few of the expensive HighEnd range.
 
I own a Denon AH-D 7000  too and the difference are not so great as the price 
 
my comparing with K702 please look this thread
http://www.head-fi.org/forum/thread/359127/akg-k702-fields-of-gold/
 

My conclusion for this K701 is: If you want to search the sound that natural, clean, spacious with great imaging, then you will not wrong to go with K701, just make sure you have decent amp to powering K701. 

Although I also own a HD800, I'm keeping my AKG K701 for its combination of comfort and performance with classical music - in which it excels. Aside from the Beyer DT-880, the most comfortable headphone currently made, the K701 has plush velour pads (though users with bigger heads may prefer a larger phone). And the illusion of head space is equal to that of the DT880 and Senn HD800, making this phone easy to wear for extended periods of time. 
 
The bass (or rather, the relative absence) is the sticking point for many. I believe that the sound is nicely balanced, but there's no question that it struggles to manage music with a more assertive bass presence. The phones have a ribbed top, and automatically adjusts to one's head size; however, many users will need to change their orientation so the phones fit perfectly all the time. Not a problem for me, but others have even tried to fix matter themselves.
 
However, I believe that this has been my best stereo investment. And if you look at the sell lists, you'll always find discounted phones for as little as $210 - a steal, in my opinion - and sometimes even less.

Similar sounding to the HD600, but is a bit brighter.

Not as bright as the DT880.

One thing that I like about these headphones is the out-of-head experience that it provides. It's like hearing the music in 3D and you can easily pick apart the instruments.

I think the weakness is the lack of bass (similar to the HD600) and maybe that it can get a bit harsh in the 2-3kHz region at times leading to a somewhat honky sound.

But the soundstage is fantastic, very similar to the HD800 in terms of presentation of sounds.

Oh and those headband bumps... glad they got rid of them in the limited edition 65th edition K702s. Maybe the K703's or whatever the next variation in the line-up will have the new headband. I wish AKG would make a new flagship.

 
I own the AKG K240 DF Studio monitor headphones, and I have been using them for more than 10 years. 
Assuming that, after so long period of time, the headphones sound quality should have improved, I decided to make a research on the market in order to find a substitute of my old headphones. 
I took into account technical specifications, reviews and prices, as well as the availability of some brands in the city where I live. 
Discarding other brands, I considered choosing between Sennheiser and AKG. Sennheiser was generally more available than AKG in all the shops I visited. But I have always used the AKG and I have been very happy with them, so, eventually I decided to keep on buying AKG headphones. 
The present AKG top model is K701 one, but the average price I found in the shops was about 350 €, which was too expensive for my budget. 
Fortunately I found a person who was selling his second hand headphones of this type at an affordable price for me. 
 
I was impressed by the incredible sound quality of the K701. The music is so detailed, so clear, so balanced and the frequency response is so extended that I doubt anybody can find anything better, at least in this price range. I have heard that there are headphones that cost even five times the price of AKG’s, but this is another world and, anyway, I have neither the chance to listen to them nor I could afford them by no means. 
I have never heard the instruments so separated and exactly situated in the sound space as I have heard with this headphones. I realised that it was time to move away my old headphones. Moreover, I have read that the sound quality of the headphones improves after 300 hours of working, so I expect a better performance after some months, if possible. 
 
If I had to change something of the headphones, I would come back to the leather pads of my old K240 DF, instead of the velour ones. But this is due to a personal problem that I suffer, being allergic to some kind of fabric. This is not AKG’s fault. 
 
I use a Cambridge Audio 340 SE amplifier to drive them. The CD player is a Sony CDP-X8920 Q series. Although I am aware that this is not the best equipment that an audiophile would desire, I think it is enough to appreciate the great sound delivered by the headphones. 
I have clearly noticed the great differences of record quality among the CD’s I own. 

Why do I like these? They are comfortable (compared to M50s IMO), they have really big sounstage and they really flat frequency response which I really like. They also come with nice stand that will keep your headphones "stored" nicely. Build quality is pretty good, but these aren't really ment to be travelled with. They are really big and can't fold at all + they also don't come with any kind of box/pouch, so these are really ment to be used at home. Another reason for that is power; they need quite some juice to sound good. They will reach some volume even with phone, but it won't sound very good. They work with Focusrite scarlett 2i4's amp pretty good, but I'm sure they will sound even better with nice amplifier. They are also open, so you don't want to take them to a train or something. 
 
I would recomend these for home use with some kind of amp for music listening and mixing (why I like them), but wouldn't use them in public since they obviously don't isolate very well. Iverall, really nice headphones I would recommend to a friend (unless he wants to use them on a go).