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.
