AKG K701 Headphone Reviews (China and Austrian Made)

[solderdude]

It's an Arya socre then!

yep.. I have not seen any correlation with that scoring and reality. Had a few conversations with Rtings (Sam) when they were starting up the headphone ratings and about this subject. They wanted a rating and had to base it on (a few in that time) measurements. This is what they came up with.

The reasoning was that it has something to do with pinna interaction so the measurements without pinna (and a substantial extra hole) and with pinna had some correlation.

 

[Luke Lemke]

yep.. I have not seen any correlation with that scoring and reality. Had a few conversations with Rtings (Sam) when they were starting up the headphone ratings and about this subject. They wanted a rating and had to base it on (a few in that time) measurements. This is what they came up with.

The reasoning was that it has something to do with pinna interaction so the measurements without pinna (and a substantial extra hole) and with pinna had some correlation.

Their measurements seem to match "subjective" reviews out there. Just based on some random headphones I checked.

Any examples of headphones they measured where the score didn't match reality?

Really interesting to know the Arya was their starting point... I didn't know that.

 

[solderdude]

Acc to Rtings HD600, HD6XX etc have a decent soundstage.
I would call it narrow for instance.

Rtings mentioned the LCD-2 has very good soundstage. Not in my experience I would say decent.
Only when EQ'ing the missing upper mids the soundstage (I prefer headstage) becomes good.

Just 2 examples. In some cases there seems to be some correlation but I see this similar as with all things in audio. Some correlation to perceived and measured response is not a clear correlation. Statistics will ensure some will appear to have a correlation and others will not when the correlation isn't there fully in reality.

 

[Robbo99999]

Acc to Rtings HD600, HD6XX etc have a decent soundstage.
I would call it narrow for instance.

Rtings mentioned the LCD-2 has very good soundstage. Not in my experience I would say decent.
Only when EQ'ing the missing upper mids the soundstage (I prefer headstage) becomes good.

Just 2 examples. In some cases there seems to be some correlation but I see this similar as with all things in audio. Some correlation to perceived and measured response is not a clear correlation. Statistics will ensure some will appear to have a correlation and others will not when the correlation isn't there fully in reality.

I agree with you on the HD600 line as another data point.

 

[Nathan Raymond]

Acc to Rtings HD600, HD6XX etc have a decent soundstage.
I would call it narrow for instance.

Rtings mentioned the LCD-2 has very good soundstage. Not in my experience I would say decent.
Only when EQ'ing the missing upper mids the soundstage (I prefer headstage) becomes good.

Just 2 examples. In some cases there seems to be some correlation but I see this similar as with all things in audio. Some correlation to perceived and measured response is not a clear correlation. Statistics will ensure some will appear to have a correlation and others will not when the correlation isn't there fully in reality.

This might be worth talking about outside this thread, but I've personally wondered if headphones with exceptional large soundstage/headstage are actually doing something wrong to create that effect, i.e. some sort of imbalance which gets perceived as more "out of the head" (and thus the "perfect" headphone is a chimera we are chasing, since the trade-offs for that hypothetical perfection are performance contradictions for what is possible in a headphone).

 

[solderdude]

With passive headphones you cannot do much trickery other than playing with the common return wire, frequency response or angling and driver-ear distance.

I have never heard a passive headphone (without special software being used) to create a spectacular soundstage in front of the head. Not talking about headtracking etc. Headstage (stereo width) is a funny thing and brain (personal) and recording related.

I have heard some headphones that have excellent imaging usually these have closely matching drivers and are angled. Imaging is the ability to sharply determine where an instrument was placed in the stereo image and which doesn't wonder about depending on the music.
Usually these headphones have a stable image and are non fatiguing to me.

You can make a new topic about this subject if you want.

 

[SamV]

Acc to Rtings HD600, HD6XX etc have a decent soundstage.
I would call it narrow for instance.

Rtings mentioned the LCD-2 has very good soundstage. Not in my experience I would say decent.
Only when EQ'ing the missing upper mids the soundstage (I prefer headstage) becomes good.

Just 2 examples. In some cases there seems to be some correlation but I see this similar as with all things in audio. Some correlation to perceived and measured response is not a clear correlation. Statistics will ensure some will appear to have a correlation and others will not when the correlation isn't there fully in reality.

One I would have liked to clarified in the soundstage scores while I still was at rtings, was that even the best passive headphone soundstage is decent, at best. So the difference between the soundstage of a pair of near-field monitors and the HD 800 S is way bigger than the difference between the soundstage of the HD 800 S and an IEM. I still think my methodology is sound though, and I've even seen Axel Grell and Dan Clark talk about soundstage in terms that would support my methodology (in their CanJam talks). Although I agree with Sean Olive that since the scoring wasn't backed by listening tests, the rankings should be taken with a pinch of salt.

 

[MayaTlab]

I still think my methodology is sound though

I don't believe that it's quite easily feasible, but for a start have you had the opportunity to try - even in an informal way - this methodology ceteris paribus but with two or more different pinnae, to at the very least verify that if headphones A activate the pinna better than headphones B with pinna X, it still holds with pinna Y ?

I started to digitise SoundStageSolo's headphones measurements between the KB5000 and KB0066 (all else ceteris paribus presumably). You'd expect that for the large over-ears that don't touch the pinna you'd see a constant transfer function between them then, but while there seems to be a general trend (that might not originate entirely from the pinna part of the, well, pinna, as the on-ears and the one in-ear they tested under such condition follow that trend to a degree as well), there is also a lot of noise around that trend with rather significant deviations as low as 2kHz or so.

 

[solderdude]

I still think my methodology is sound though, and I've even seen Axel Grell and Dan Clark talk about soundstage in terms that would support my methodology (in their CanJam talks). Although I agree with Sean Olive that since the scoring wasn't backed by listening tests, the rankings should be taken with a pinch of salt.

The pinna does have to do with headstaging.
measuring with and without pinna shows the differences. You are the only one doing this as far as I know. I like the idea.
A question: When you measured with and without pinna was the complete pinna + mounting plate replaced by a flat plate and was that hard plastic or rubberized ?

The differences you got with an without pinna do not match with the differences between say my pinna less and Amirs HATS measurements.
Your differences see much larger.

Then my view on the soundstage measurements. I know you had to create a number and weigh it into the other numbers. I like the idea.

The problem I have with it (the grain of salt as it were) is that you seem to base it on the 10kHz dip (caused by the pinna shape) which may be an indication of angle of the driver but can be skewed by driver diameter and position. The 10kHz dip would occur at a different frequency with actual ears. Probably between 6kHz and 12kHz or so ? The driver may have different behavior at those frequencies.

I'd like to see more research done in this field, as S. Olive also mentioned, with a larger group.
The difficulty could be that the whole 'headstage' effect seems to differ from person to person and I suspect not only because of different pinna shapes and ear canals but also the way the brain processes the incoming 'data'.

It seems like a difficult subject that before one starts to but out numbers folks would base purchases on that feel this is an important aspect should be researched a bit more. I know.. expensive and more something that could be done by some well funded organization perhaps.

I would like to encourage you to look further into this (no one else seems to be doing this) with a more elaborate study using interested people in the staging aspect.
Perhaps your testing of the 2 incoming HATS (congrats with the new job b.t.w.) can give some pointers. Looking forward to some results.

 

[SamV]

I don't believe that it's quite easily feasible, but for a start have you had the opportunity to try - even in an informal way - this methodology ceteris paribus but with two or more different pinnae, to at the very least verify that if headphones A activate the pinna better than headphones B with pinna X, it still holds with pinna Y ?

I started to digitise SoundStageSolo's headphones measurements between the KB5000 and KB0066 (all else ceteris paribus presumably). You'd expect that for the large over-ears that don't touch the pinna you'd see a constant transfer function between them then, but while there seems to be a general trend (that might not originate entirely from the pinna part of the, well, pinna, as the on-ears and the one in-ear they tested under such condition follow that trend to a degree as well), there is also a lot of noise around that trend with rather significant deviations as low as 2kHz or so.

Haven't had that chance yet. That would require two different HATS, and extra ears for each to chop of their pinnae, which would be quite costly.

I wouldn't expect a constant transfer function between KB5000 and KB0066 (were they using the same coupler?). I think the size and angle of the driver would mean that different area of the ear would be activated by different headphones, which could cause some non-linearities in the transfer function. We did get quite a bit of noise in our measurements though, but mostly with smaller earcups. I haven't looked at PRTF measurements in a long time, so my memory of the test results is a bit fuzzy.

Today, I learned what ceteris paribus mean!

 

[SamV]

The pinna does have to do with headstaging.
measuring with and without pinna shows the differences. You are the only one doing this as far as I know. I like the idea.
A question: When you measured with and without pinna was the complete pinna + mounting plate replaced by a flat plate and was that hard plastic or rubberized ?

The differences you got with an without pinna do not match with the differences between say my pinna less and Amirs HATS measurements.
Your differences see much larger.

Then my view on the soundstage measurements. I know you had to create a number and weigh it into the other numbers. I like the idea.

The problem I have with it (the grain of salt as it were) is that you seem to base it on the 10kHz dip (caused by the pinna shape) which may be an indication of angle of the driver but can be skewed by driver diameter and position. The 10kHz dip would occur at a different frequency with actual ears. Probably between 6kHz and 12kHz or so ? The driver may have different behavior at those frequencies.

I'd like to see more research done in this field, as S. Olive also mentioned, with a larger group.
The difficulty could be that the whole 'headstage' effect seems to differ from person to person and I suspect not only because of different pinna shapes and ear canals but also the way the brain processes the incoming 'data'.

It seems like a difficult subject that before one starts to but out numbers folks would base purchases on that feel this is an important aspect should be researched a bit more. I know.. expensive and more something that could be done by some well funded organization perhaps.

I would like to encourage you to look further into this (no one else seems to be doing this) with a more elaborate study using interested people in the staging aspect.
Perhaps your testing of the 2 incoming HATS (congrats with the new job b.t.w.) can give some pointers. Looking forward to some results.

We got an extra rubber ear and chopped its pinna off. It was identical to the regular one we used except that it didn't have the outer ear.

The 10kHz dip was one of the calculations we did. Another one was the amount of pinna effect (boost). I believe the 10kHz is the result of a cancelation that's happening, so if it happens at a different frequency on a different head it shouldn't be affected by the headphones behavior in at that frequency. It's just a phase cancellation due to a reflection. Each brain knows where that cancellation occurs in its ear for sounds that are coming from 30 degrees in front. Am I missing something? (it's too early here, my brain hasn't fully booted up yet).

I'm not quite sure yet if I will develop a soundstage test at my new job. As you mentioned it requires quite a bit of resources, is rather damaging to the HATS (replacing the ear for each measurement), and the results were not consistent. I'm trying to go the legitimate route than the experimental route here. But if you guys think it would be beneficial, I'm open to looking into it again when I have the time. Although, I still believe I was measuring a real phenomena, the HD 800 S (and the large Hifiman headphones) really have a different soundstage.

 

[solderdude]

the HD 800 S (and the large Hifiman headphones) really have a different soundstage.

Yep they do.

We got an extra rubber ear and chopped its pinna off. It was identical to the regular one we used except that it didn't have the outer ear.

Ah cleared up... didn't know that. Still the measured differences, for some reason, were bigger than those between my an Amirs rig.

I would welcome sensitivity numbers (dB/V), ear space, clamping force, weight, impedance (incl. variance) etc, power rating, compression.
Basically the specs I measure as well so it is all in one place and easy to find.
Or is it all in videos only ?

The soundstage/imaging is hard to really quantify as it is also recording and individual dependent.

 

[SamV]

I would welcome sensitivity numbers (dB/V), ear space, clamping force, weight, impedance (incl. variance) etc, power rating, compression.
Basically the specs I measure as well so it is all in one place and easy to find.
Or is it all in videos only ?

Cool, most of those are already on my list. I don't think it's going to be video-only.

 

[192kbps]

Looking forward to someone sending the 612PRO, I think they are the best AKG headphones I've ever heard.

 

[solderdude]

hint: K702 vs K612Pro

Essentially a K702 but with non replaceable cable.

 

[Alchemist_]

What is the inner diameter of the ear cups? And what is the depth?
Versions sold in 21/22 as I understand it, these are Chinese versions.

PS (somewhere they write 60, but somewhere 70? The difference is significant.)

 

[600_OHM]

A wire in the headband would pick up the same amount of RF.
Most headphone cables are not screened at all so a cable would pick up way more than the rods.

Yeah, some portable radios (even some cell-phones with fm tuners) rely on your headphone cable to be the antenna.

I use some of my cans in an rf-environment where I actually have to wrap a few turns around a ferrite core. Had to do this too inside the transmitter room.

BUT - omg - why didn't I think of this for home users. In addition to cables made from moon-dust, I could have also been offering golden-ferrites! "Digital ready" of course.

 

[newaudioguy77]

@amirm
"I can't recommend either version of AKG K701 without EQ. With EQ, they are fine."
That's your opinion sir. For me K701 where one of the most enjoyable headphones I have ever listen to. Without of any EQ whatsoever. Why? Because of simple fact that everyone hearing is different. We literally percept different frequencies differently. On top of that there is also that soo much depends on taste and individual expectations. Some preferer a lot of bass others a lot of treble. Some like it neutral. Some liked Harman curve. Others like V-shaped and so on. To my mind reviewing headphones based on graph and how well you can bring them using EQ to specific sound profile you like... is a bit pointless.
I highly respect your equipment (dacs, amp etc.) measurements. but headphones review is a bit .... Its like talking about art in my humble opinion.

Are you really "standing up" for a pair of headphones?

You know, headphones don't have feelings or a soul. I don't think animals or humans do either, but that's a story for a different day.

The headphone reviews on this site are awesome. These reviews give us details that we would otherwise be guessing about with respect to frequency response and distortion etc.

Then you talk about subjective opinions of what "sounds good"to different people. But actually, that viewpoint is much like art, or worse yet, the discipline of philosophy and rudimentary human psychology.

Thank God for Amir. Really. He is literally the next Tyll Hertsens, but with a stronger focus on the importance of measurements.

I won't compete with a machine when it comes to measuring audio fidelity.

 

[192kbps]

https://twitter.com/i/web/status/1545496304456912896

 

[stevenswall]

Wasn't this used by Quincy Jones during the creation of Michael Jackson's "Thriller" album? Crazy that it's not that great. I wonder if the Q701 is any better.