AKG K712 Pro Review (Headphone)

[bartosso]

You know what, you mention 2900Hz peak that you seem to have identified (I guess by playing sine tones)

I also used this handy tool on Crinacle's site (link):

I must say I dropped the oratory EQ for now, I think I like my own EQ better. It has a tad more presence in the 40-80 Hz range, making the bass warmer and punchier without descending into distortion by boosting the sub-bass too much (I boost the sub-bass by around 7,2 dB in comparison to 8,5 in Oratory's EQ). In comparison to oratory's, the treble doesn't feel so bright and the upper mids so shouty (I'd say it's a flattened Harman, but I preferred to preserve some of the K712's mid presence so they keep a hint of their character without sounding... eh, a bit like sh*t, which they do without EQ, sadly).

But one thing to be certain on before you go down the route of trying to tune by identifying peaks from sine tones - your hearing can have localised peaks & dips throughout the frequency range "in real life" when listening to sounds that don't come from headphones, therefore you wouldn't correct such personal hearing anomalies in your headphones, as that would be unnatural. For instance, I know I've got a massive peak in my hearing between 8-12kHz which I first noticed in headphones, but then I tested to see if I had the same peak when listening to perfectly flat anechoic EQ'd speakers (ie my 308p Mkii speakers) and I have the same large natural peak in my hearing between 8-12kHz, therefore I don't correct that peak in headphones. So you have to be careful about using sine tones in headphones as a means to decide whether you EQ them

Interesting, I've never thought about this. I think I'll check this 3kHz and 6-7 kHz peak with my other audio devices, maybe it will turn out it's my hearing and not the headphones. As is, however, I do like the sound of the K712 with my current EQ quite a bit, will continue to experiment in-between music sessions. Thanks again for your help.

 

[Robbo99999]

I also used this handy tool on Crinacle's site (link):
View attachment 229165

I must say I dropped the oratory EQ for now, I think I like my own EQ better. It has a tad more presence in the 40-80 Hz range, making the bass warmer and punchier without descending into distortion by boosting the sub-bass too much (I boost the sub-bass by around 7,2 dB in comparison to 8,5 in Oratory's EQ). In comparison to oratory's, the treble doesn't feel so bright and the upper mids so shouty (I'd say it's a flattened Harman, but I preferred to preserve some of the K712's mid presence so they keep a hint of their character without sounding... eh, a bit like sh*t, which they do without EQ, sadly).


Interesting, I've never thought about this. I think I'll check this 3kHz and 6-7 kHz peak with my other audio devices, maybe it will turn out it's my hearing and not the headphones. As is, however, I do like the sound of the K712 with my current EQ quite a bit, will continue to experiment in-between music sessions. Thanks again for your help.

Good point about not boosting the sub-bass too much. I have the K702 which is a very similar design to the K712, and I don't use the Oratory EQ for that headphone either....in fact one of the worst things to do with the K702 is to boost 20Hz to Harman levels with the K702 in my experience - it dulls the headphone considerably. My EQ is based on his measurements though, so of course that's very useful that he measured them and makes it all possible, but I only boost it to Harman Bass at the 35Hz point and it rolls off slowly so it's 4dB down from Harman at 20Hz. My HD560s on the other hand can take Harman boosted bass down to 20Hz, same is true for the planar HE4XX I have, and also the closed back NAD HP50, but not for my K702 and not for my HD600.

EDIT: mind you Oratory doesn't boost the K712 to Harman at 20Hz, he's 3dB down from that at 20Hz, with a roll off starting from 30Hz - it is still more bass than I choose to configure my similarly designed K702 though, and I certainly configure my K702 with an earlier roll-off than Oratory does with the K702 as he has that one at Harman bass all the way down to 20Hz.

 

[dante21]

are these worth for someone who owns a 560s and looks for something different?

are these warm?

 

[staticV3]

@dante21 you could call the K712 warm, but tbh it just sounds bad. Not even EQ can save this headphone imo. An HE400se or a used HD600 would be much better purchases.

 

[Robbo99999]

are these worth for someone who owns a 560s and looks for something different?

are these warm?

I think if you live in Europe or UK it would be better to get the K702, because they're similar in earcup and I guess driver design but K702 have angled pads and they'll be cheaper than buying a K712 in Europe or UK, but I'd recommend you EQ them (K702) using the Oratory EQ. They do have a different experience than the HD560s after EQ, soundstage is a bit wider and vocals not as much in your face. HD560s is a better headphone overall though, with lower unit to unit variation and lower distortion. K702 can have some reliability issues with solder failing on the wires in the earcups which means you'd have to solder them back on - if you treat them roughly then they're more likely to detach & require resoldering. It is a different experience to the HD560s though in my view. I think the K702 is good value if you get it in UK or Europe especially when on sale, but K702 is really quite expensive for some reason in the USA last time I looked.

EDIT: although K702 has shot up in price the last couple of weeks, so I wouldn't buy it at the price it's at now. I'd buy it for £100.

 

[bartosso]

@dante21 you could call the K712 warm, but tbh it just sounds bad. Not even EQ can save this headphone imo. An HE400se or a used HD600 would be much better purchases.

I happen to have both the AKG K712 and the Hifiman HE400SE. I wouldn't go as far as to say that K712 is bad, but I personally had to develop my own EQ for them to make them sound good. The oratory one and other auto-generated EQs just sounded like trash. In my experience, the dip in low treble hits the bottom around 3500Hz and not 3000Hz as most measurements indicate and the hp is much sharper in the 6kHz - 8kHz range in reality. The oratory EQ boosts 3kHz way above the target while the response takes a dive above 3,2kHz where it actually needs the biggest boost. Might be my unit, though, hard to tell, but both drivers have this tonality, so it seems unlikely. Or it's just the shape of my ears.

dante21 said:
are these worth for someone who owns a 560s and looks for something different?

I don't think so.

are these warm?

Not really.

As stated by staticV3, HE400SE is a much better bang for the buck and it actually sounds better than K712 for the most part, except for the spatial qualities where K712 shines more. In my opinion, all but one flaw of K712 can be fixed with EQ, and that one flaw is the response below 30 Hz. You can't get the sub-bass exactly right on K712 while on HE400SE, it's a cakewalk due to its low distortion. Still, with a good amp, the bass on K712 is absolutely OK.

 

[lewdish]

are these worth for someone who owns a 560s and looks for something different?

are these warm?

Warmer than the 560S yeah, I think the 560S has a more coherent sound though

 

[bequietjk]

K712 hooked up to my Denon AVR sounds amazing. Rock music sounds so damn impactful and engaging. Can't say the same when the K712 are hooked up to some other headphone amps.

 

[dante21]

I happen to have both the AKG K712 and the Hifiman HE400SE. I wouldn't go as far as to say that K712 is bad, but I personally had to develop my own EQ for them to make them sound good. The oratory one and other auto-generated EQs just sounded like trash. In my experience, the dip in low treble hits the bottom around 3500Hz and not 3000Hz as most measurements indicate and the hp is much sharper in the 6kHz - 8kHz range in reality. The oratory EQ boosts 3kHz way above the target while the response takes a dive above 3,2kHz where it actually needs the biggest boost. Might be my unit, though, hard to tell, but both drivers have this tonality, so it seems unlikely. Or it's just the shape of my ears.


I don't think so.

Not really.

As stated by staticV3, HE400SE is a much better bang for the buck and it actually sounds better than K712 for the most part, except for the spatial qualities where K712 shines more. In my opinion, all but one flaw of K712 can be fixed with EQ, and that one flaw is the response below 30 Hz. You can't get the sub-bass exactly right on K712 while on HE400SE, it's a cakewalk due to its low distortion. Still, with a good amp, the bass on K712 is absolutely OK.

yeah, but the 400se is a bit like the 560s. Bright-neutral

 

[vco1]

I like mine. No EQ, just connected to a Topping DX7Pro. Think they're comfortable too.

Perhaps it's because a lack of 'training' or maybe my hearing is bad. But to me these just sound fine.

 

[OCA]

This is a review and detailed measurements of the AKG K712 Pro open back (gaming?) headphone. It is on kind loan from a member and costs US $327 on Amazon.

I find the K712 cute and cheerful:


View attachment 166565

The huge cups (64mm inside diamater/24mm deep) fit over my ear fine. But I thought the cups didn't compress enough and after a while, I could feel their slight pressure on head. Ditto for the headband. I would rate it as 90% comfortable.

Plastic components help keep the weight lower:
View attachment 166570

A mini XLR socket is provided which you can use to create balanced or unbalanced connection. I used the aftermarket nice twisted cable the owner had supplied.

Note: The measurements you are about to see are made using a standardized Gras 45C. Headphone measurements by definition are approximate and variable so don't be surprised if other measurements even if performed with the same fixtures as mine, differ in end results. Protocols vary such as headband pressure and averaging (which I don't do). As you will see, I confirm the approximate accuracy of the measurements using Equalization and listening tests. Ultimately headphone measurements are less exact than speakers mostly in bass and above a few kilohertz so keep that in mind as you read these tests. If you think you have an exact idea of a headphone performance, you are likely wrong!

The large cups made an easy job of mounting them on my fixture and getting good measurements on first try.

AKG K712 Pro Measurements
Let's start with our usual frequency response measurements:

View attachment 166571

Compliance with our target is only in the 200 to 500 Hz (I calibrate to 420 Hz). Very hard to imagine what they were thinking in the response between 500 Hz and 5 kHz. There is massive shortfall. We also have the usual bass droop.

Relative response shows that we need very large compensation at 4.5 kHz:
View attachment 166572

Distortion is very good at lower levels:

View attachment 166577

View attachment 166578

Impedance at 1 kHz is same as advertised but is variable:

View attachment 166579

Bass tuning is at 100 Hz and hence the reason response drops below that.

View attachment 166580

They are not very sensitive so you definitely need a headphone amp:
View attachment 166582

Group delay is reasonable in balance:

View attachment 166581

AKG K712 Pro Listening Tests and Equalization
I only listened for a minute before reaching for EQ. It sounded very closed and improper to me out of box. EQ development is a bit challenging due to troughs not matching the shape of a parametric filter. Still, I lucked out and with just three filters massively improved the response:

View attachment 166583

High level of filter amplitude causes easy clipping so I had to pull the overall levels down which means you need even more drive from your amplifier. I also could not push the bass enough as distortion would set in. As is, deep bass was good with EQ.

I really enjoyed the spatial qualities that equalization brought to these large drivers/cups. Turning off the EQ made this collapse. As usual, this is caused by lack of energy in the 2 to 5 kHz without EQ.

Conclusions
I was very surprised at the response of this headphone. I looked up the announcement data and it was 2013. I think Harman had already performed its headphone research by then. So I have to think the AKG folks were not on board with it in development of K712 Pro as it doesn't remotely comply with their preference curve. And if any headphone needs to comply with that standard is the K712. It is impossible to make a case that you want to filter out all the music spectrum in 1.3 and 3.4 kHz!

I can't recommend the K712 Pro without EQ. With EQ, I am not super happy with deep bass response but spatial qualities are good enough to push me to put it on my recommended list.

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As always, questions, comments, recommendations, etc. are welcome.

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Dear Amirm,


I have this headphone. I bought it after reading countless reviews about what the cheapest descent sounding headphone was. I agree with you 100% that I was a bit disappointed to hear the odd out of the box frequency response. But as you have pinpointed in just 3 bands (the perfect correction for this headphone is listed on the web and consists of 7 bands which in sum are similar to your 3 band casual EQ suggestion - which amazes me btw, no offense but your empirical approach to digital filters scares me but you've the ears of a bat) it only sounds good after EQ. I think the reason studio engineers like K712 is because of its hidden potential to sound very good after just a simple free EQ. Noone talks about this but with a headphone you've the freedom to completely ignore Harman target, shoot for dynamics, frequency range and what have you and leave the target to DRC. And DRC will totally work on a headphone unlike the case with a speaker as you are not trying to force a random room to be minimum phase.

 

[SmartCheetah]

@Serkan what 7 bands correction are you referring to, can you share it, please?

 

[OCA]

AutoEq/results/rtings/rtings_harman_over-ear_2018/AKG K712 PRO at master · jaakkopasanen/AutoEq

Automatic headphone equalization from frequency responses - AutoEq/results/rtings/rtings_harman_over-ear_2018/AKG K712 PRO at master · jaakkopasanen/AutoEq

github.com

 

[derbidrd]

AutoEq/results/rtings/rtings_harman_over-ear_2018/AKG K712 PRO at master · jaakkopasanen/AutoEq

Automatic headphone equalization from frequency responses - AutoEq/results/rtings/rtings_harman_over-ear_2018/AKG K712 PRO at master · jaakkopasanen/AutoEq

github.com

Thank you for sharing this website : I tried most of the parametric EQ and like this one more (Kuulokenurkka) :

Preamp: -6.8 dB
Filter 1: ON LSC Fc 105 Hz Gain 6.8 dB Q 0.70
Filter 2: ON PK Fc 181 Hz Gain -3.5 dB Q 0.21
Filter 3: ON PK Fc 1226 Hz Gain 5.5 dB Q 1.41
Filter 4: ON PK Fc 3132 Hz Gain 5.0 dB Q 3.74
Filter 5: ON PK Fc 2200 Hz Gain -4.1 dB Q 3.95
Filter 6: ON HSC Fc 10000 Hz Gain 1.4 dB Q 0.70
Filter 7: ON PK Fc 5921 Hz Gain -3.4 dB Q 6.00
Filter 8: ON PK Fc 5111 Hz Gain 1.9 dB Q 5.09
Filter 9: ON PK Fc 64 Hz Gain -0.6 dB Q 1.81
Filter 10: ON PK Fc 32 Hz Gain 0.8 dB Q 3.02

Also a big thank you for you youtube videos about audyssey calibration, you rock !

 

[OCA]

Thank you for your kind words. This is the one I use lately and I quite like it. They even supply convolution FIR filters for 44.1/48kHz sampling rates for headphones:

AutoEq/results/Headphone.com Legacy/over-ear/AKG K712 at master · jaakkopasanen/AutoEq

Automatic headphone equalization from frequency responses - jaakkopasanen/AutoEq

github.com

 

[Mark K]

Aside from not fitting (pin 4 preventing that) the pinning is also very different. (picture from Hart cables)

View attachment 166608

K712 Pro, was the very first pair of headphones I really like. Nevertheless I found myself difficult to like K702...Anyway I have been trying to find a balanced wire but were told by various manufacturers telling me that K712pro accepts only SE wires.

 

[staticV3]

Anyway I have been trying to find a balanced wire but were told by various manufacturers telling me that K712pro accepts only SE wires.

Correct. The cable jack inside the ear cup needs to be modified to accept balanced cables.

See post #9.