*NEW* AKG K702 has been measured by Oratory!

[Robbo99999]

Fairly typical needing bass boost and various random peaks in the high end.

Yes, indeed, although there's not really any nasty peaks or dips that are difficult to correct with EQ, so it's a good one to EQ I think. I purposefully asked Oratory for the extra graphs/info I showed in the first post of this thread, to try and make it a little bit like a review, seeing as Amir hasn't measured this headphone yet. I'd still quite like to see Amir measure this headphone....I don't think he'd like the distortion peaks at 1250 and 2000Hz given the high SPL he does distortion measurement 94dB/104dB/114dB....but that may not sully his listening impressions, but we'd have to see. My little experimentations to determine my max theoretical listening levels showed I listen to a 0dBFS signal at about anything from 80-86dB depending on headphone or inaccuracy of my experiment, so really only the 94dB level he tests has any relevance to me, and even that is extreme given my listening levels. But yeah, I'd like to see Amir review the headphone, out of curiosity and indeed another data point.

 

[Robbo99999]

Channel matching really has a bit of a catch, but it's pretty good, less than 1db of difference.
My intention is to fine tune the equalizations, since I have been able to verify that not all headphones of the same model measure the same.
The culprit is an LCD2 that I have and it doesn't work well with any EQ I've found, they sound horrible with them.
Now I have to learn to import the Harman curve and test equalizations, although it works quite well by eye.
I also need to visualize the curve as it appears in the reviews, as sloping upwards, but I have not been able to do it.

I think your measurements are good at showing the channel matching, but unfortunately it's not that valid for you to use your measurements to EQ to the Harman Curve. The Harman Curve is only compatible with the GRAS measurement devices, as they are most similar to the kit used in the original Harman research.....so unfortunately you can't really use the Harman Curve on your home made measurement rig. You may be able to use your measurements in other ways to give you some guideance to EQ your headphone, but you won't be able to use the Harman Curve.

 

[Fernando]

I think your measurements are good at showing the channel matching, but unfortunately it's not that valid for you to use your measurements to EQ to the Harman Curve. The Harman Curve is only compatible with the GRAS measurement devices, as they are most similar to the kit used in the original Harman research.....so unfortunately you can't really use the Harman Curve on your home made measurement rig. You may be able to use your measurements in other ways to give you some guideance to EQ your headphone, but you won't be able to use the Harman Curve.

I still do not have enough information to refute this claim, but I think it is not entirely true.
We will continue to investigate and compare...

 

[Robbo99999]

I still do not have enough information to refute this claim, but I think it is not entirely true.
We will continue to investigate and compare...

The Harman Curve for headphones was created by placing a dummy head with specific design of ears/pinna in the Harman listening room at the listening point with 2 very high quality & high preference rated speakers as playback devices in the room. They then did frequency sweeps through the speakers and recorded the response of those sweeps with microphones in the ears of the dummy head....this created the basis of the Harman Curve. They then EQ'd a K712 headphone to this curve that they had measured, when placed on the same dummy head, thereby trying to replicate the sound of the speakers in the room. Then they gave this headphone to a group of listeners within the research to listen to music, and the participants were able to tweak tone controls to their liking for bass (& I think treble)....they then collated the patterns and trends of the preferred tweakings of the participants in how that related to the modification of the initial curve they had created, thereby creating the Headphone Harman Curve as we know it. So the Headphone Harman Curve is a combination of actual measurements of a dummy head in a listening room (to capture some HRTF effects to make headphone listening a more natural "speaker-like" experience) & also a combination of user preference.

Seeing as the Harman Curve is based on an initial measurement of a specific dummy head in a room with a specific design of ear/pinna, then the curve is specific to equipment that mimics the ear/pinna design of the original research - because different ear/pinna design will influence the frequency response when the same headphone is measured. So if you use the Harman Target Curve on your homemade measurement device which is god knows what outer ear and ear canal design, then your headphone measurements will not reflect the same frequency responses that would have been measured on the original research equipment, therefore EQ'ing your headphone to the Harman Curve would be a nonsense because you're starting off with an erroneous measurement, thereby invalidating the research & invalidating the Harman Curve in your proposed usage case.

 

[Fernando]

The Harman Curve for headphones was created by placing a dummy head with specific design of ears/pinna in the Harman listening room at the listening point with 2 very high quality & high preference rated speakers as playback devices in the room. They then did frequency sweeps through the speakers and recorded the response of those sweeps with microphones in the ears of the dummy head....this created the basis of the Harman Curve. They then EQ'd a K712 headphone to this curve that they had measured, when placed on the same dummy head, thereby trying to replicate the sound of the speakers in the room. Then they gave this headphone to a group of listeners within the research to listen to music, and the participants were able to tweak tone controls to their liking for bass (& I think treble)....they then collated the patterns and trends of the preferred tweakings of the participants in how that related to the modification of the initial curve they had created, thereby creating the Headphone Harman Curve as we know it. So the Headphone Harman Curve is a combination of actual measurements of a dummy head in a listening room (to capture some HRTF effects to make headphone listening a more natural "speaker-like" experience) & also a combination of user preference.

Seeing as the Harman Curve is based on an initial measurement of a specific dummy head in a room with a specific design of ear/pinna, then the curve is specific to equipment that mimics the ear/pinna design of the original research - because different ear/pinna design will influence the frequency response when the same headphone is measured. So if you use the Harman Target Curve on your homemade measurement device which is god knows what outer ear and ear canal design, then your headphone measurements will not reflect the same frequency responses that would have been measured on the original research equipment, therefore EQ'ing your headphone to the Harman Curve would be a nonsense because you're starting off with an erroneous measurement, thereby invalidating the research & invalidating the Harman Curve in your proposed usage case.

I understand, but for that reason it would only work with an inner ear the same as the one used and with akg712. (muddy in its mid / low zone). I gather it's just for guidance then.

You could try to measure your akg702 and compare with oratory, just out of curiosity.

Thx for the info!!!

 

[Robbo99999]

I understand, but for that reason it would only work with an inner ear the same as the one used and with akg712. (muddy in its mid / low zone). I gather it's just for guidance then.

You could try to measure your akg702 and compare with oratory, just out of curiosity.

Thx for the info!!!

The Headphone Harman Curve is supposed to work with any headphone that's measured on a GRAS device, because they're the only measurement kits that are compatible with the Harman Curve. It's true that people's anatomy of outer ear & inner ear will vary to some degree or a lot from the equipment used in the Harman Research, as well as their overall head shape (which would effect the HRTF that's built into the Harman Curve)....so those are often the reasons for people not liking the Harman Curve, but by definition of the research most people prefer the Harman Curve.

I'm not interested in measuring my K702 on any home rig, as mine has already been measured by Oratory (the reason why this thread is happening)....and I also know enough to know that any home rig work is less valid than the Oratory measurement and any measurement I do on my own improvised rig would not be compatible with the Harman Curve. Additionally I like the Harman Curve, so no need for me to mess around trying to cobble together a home made measurement rig.

 

[Fernando]

The Headphone Harman Curve is supposed to work with any headphone that's measured on a GRAS device, because they're the only measurement kits that are compatible with the Harman Curve. It's true that people's anatomy of outer ear & inner ear will vary to some degree or a lot from the equipment used in the Harman Research, as well as their overall head shape (which would effect the HRTF that's built into the Harman Curve)....so those are often the reasons for people not liking the Harman Curve, but by definition of the research most people prefer the Harman Curve.

I'm not interested in measuring my K702 on any home rig, as mine has already been measured by Oratory (the reason why this thread is happening)....and I also know enough to know that any home rig work is less valid than the Oratory measurement and any measurement I do on my own improvised rig would not be compatible with the Harman Curve. Additionally I like the Harman Curve, so no need for me to mess around trying to cobble together a home made measurement rig.

I have done it and it's fun.
Another point of view is always welcome, even if it is wrong.
And sometimes there are surprises !!

 

[Robbo99999]

What you were hoping for ? Any surprises? Is the fresh pad measure similar to Crinacle's ?

Ok folks, as you probably know both Crinacle's & Oratory's measurement kit are GRAS devices that are compatible with the Harman Curve, and both guys have measured the K702, so what I've done here is overlayed the results of their two measurements:

As you can see they are strikingly similar with one exception, and that is the 5500Hz peak which is present in Oratory's but not in Crinacles. Oratory measured my K702 and his channel matching graph shows that one of the drivers in my K702 has some characteristics of the Crinacle measurement, as in less of a steep dip after the 2500Hz peak (the right driver, the red line):

So given that both Oratory's & Crinacle's measurements are almost spot on with each other apart from the 5500Hz peak and given that one of my drivers that Oratory measured follows some characteristics closer to Crinacle's measurement, then I figured it would be valid to take an average of both Oratory's & Crinacle's measurement, for EQ purposes, as it's like having 2 headphones measured rather than one, therefore taking into account some unit to unit variation:

You can see the average line being the highlighted green line in the above screenshot. So I did an EQ based on this average of Oratory's & Crinacle's measurement (and also see the attached EqualiserAPO config file at the end of the post, if you want to try this EQ):

I think I do prefer this EQ which is an amalgamation of both Oratory's & Crinacle's measurement....(note I'm testing this on my 2nd pair of K702 that Oratory hasn't measured, he still has my first pair....and when I get back that first pair from him then it'll be better for me to use his EQ rather than this amalgamation on that particular headphone). I think this takes a bit of harshness away from an EQ based on the Crinacle measurement, yet gives a bit more sparkle and spatial qualities to the Oratory EQ. Note that I also put in a High Pass Filter to remove the EQ boost below 30Hz which I find further enhances spatial qualities and general clarity. That's a High Pass Filter at 25Hz with Q0.84. I've found that adding the same High Pass Filter to Oratory's EQ is also a preference for me, so you could try just adding that filter to his EQ rather than trying my EQ above (the amalgamation of Oratory's & Crinacle's measurement) if you so desire.

Yes, so there you have it, a comparison between Oratory's & Crinacle's measurement of the K702 and additionally my EQ which is a combination of them both, thereby taking into account some unit to unit variation.

 

[paolomo]

Ok, let me first say that I admire your commitment and your work on this, so please don't take my reply as "internet hate" I just want to warn you about the risks of taking the average of only two data sets. Averages have a statistical meaning only when you take them across a population of many, not 2, 3, or even 10. With such small numbers your result may be severely biased by outliers. So maybe sample A is the more common one and sample B is an outlier, and taking the average you end up with a result that suggests that the more common occurrence is in the middle, while in fact it's simply A.

I think the discrepancy you found is very interesting and definitely deserves further investigation. Maybe tester B does something wrong (I'm talking about a generic tester). Maybe there are two batches of the same product. Imagine that: those that have batch A have a pair of headphones that is perfectly served by curve A, and an average of A and B would just be suboptimal.

So by all means, keep experimenting and asking questions to the people involved in this. Mine is just a (hopefully constructive) remark on the method.

 

[Robbo99999]

Ok, let me first say that I admire your commitment and your work on this, so please don't take my reply as "internet hate" I just want to warn you about the risks of taking the average of only two data sets. Averages have a statistical meaning only when you take them across a population of many, not 2, 3, or even 10. With such small numbers your result may be severely biased by outliers. So maybe sample A is the more common one and sample B is an outlier, and taking the average you end up with a result that suggests that the more common occurrence is in the middle, while in fact it's simply A.

I think the discrepancy you found is very interesting and definitely deserves further investigation. Maybe tester B does something wrong (I'm talking about a generic tester). Maybe there are two batches of the same product. Imagine that: those that have batch A have a pair of headphones that is perfectly served by curve A, and an average of A and B would just be suboptimal.

So by all means, keep experimenting and asking questions to the people involved in this. Mine is just a (hopefully constructive) remark on the method.

Yeah, that's cool, you don't have to preach to me on subjects of statistics or the scientific method, I'm familiar with both according to schooling & prior work. If you use your logic then you can't base an EQ on one headphone only, which is Oratory's EQ, that's my headphone being measured, one headphone. Crinacle also measured one headphone. I've taken the average of the two given that there were a lot of similarities to try to account for unit to unit variation. Amir measures one headphone, are you not gonna use his EQ's or pay heed to his measurements?? Do you think it's more valid to use an EQ based off measurement of one headphone or two?? You don't know if one is an outlier or not until you've measured loads of headphones of the same model....Oratory has done this with some headphones, eg the Hifiman HE4XX and he said variation of that headphone was very low. I've already asked Oratory what he thinks to the differences between Crinacle's & his own measurements, linking him my prior post (not heard back yet). The point is, you work with what you've got & make the best of it....that's what I'm doing.

As far as is known in "internet lore", there is only one version of the K702, in terms of how they measure. Yes, there's the original Austrian version & then the later Chinese version, but they're supposed to be the same, just the manufacturing location was changed for economical reasons.

I think taking an average of the 2 headphones being measured, as I have done, is a valid approach, you've not dissuade me on that.....I'm well aware of the scientific method and elements of statistics, so you don't have to point that out.

 

[paolomo]

Yeah, that's cool, you don't have to preach to me on subjects of statistics or the scientific method, I'm familiar with both according to schooling & prior work. If you use your logic then you can't base an EQ on one headphone only, which is Oratory's EQ, that's my headphone being measured, one headphone. Crinacle also measured one headphone. I've taken the average of the two given that there were a lot of similarities to try to account for unit to unit variation. Amir measures one headphone, are you not gonna use his EQ's or pay heed to his measurements?? Do you think it's more valid to use an EQ based off measurement of one headphone or two?? You don't know if one is an outlier or not until you've measured loads of headphones of the same model....Oratory has done this with some headphones, eg the Hifiman HE4XX and he said variation of that headphone was very low. I've already asked Oratory what he thinks to the differences between Crinacle's & his own measurements, linking him my prior post (not heard back yet). The point is, you work with what you've got & make the best of it....that's what I'm doing.

As far as is known in "internet lore", there is only one version of the K702, in terms of how they measure. Yes, there's the original Austrian version & then the later Chinese version, but they're supposed to be the same, just the manufacturing location was changed for economical reasons.

I think taking an average of the 2 headphones being measured, as I have done, is a valid approach, you've not dissuade me on that.....I'm well aware of the scientific method and elements of statistics, so you don't have to point that out.

It was not my intention to preach. Plus, I am sure you have the whole headphone situation covered in your study. You certainly considered all the variables. My comment was on the statistical aspect and the statistical aspect alone. I have no interest in dissuading you from taking the average of 2 points. It just holds no statistical meaning whatsoever - the law of large numbers is called that way for a reason. For small data sets, averages are misleading tools.

As you correctly say, one works with what one has, one can't change that. Here everybody contributes what they can, then you are of course free to do your thing. And yes, a lot of preaching happens in forums, I get it. But I can guarantee you I have no interest in that.

 

[Robbo99999]

It was not my intention to preach. Plus, I am sure you have the whole headphone situation covered in your study. You certainly considered all the variables. My comment was on the statistical aspect and the statistical aspect alone. I have no interest in dissuading you from taking the average of 2 points. It just holds no statistical meaning whatsoever - the law of large numbers is called that way for a reason. For small data sets, averages are misleading tools.

As you correctly say, one works with what one has, one can't change that. Here everybody contributes what they can, then you are of course free to do your thing. And yes, a lot of preaching happens in forums, I get it. But I can guarantee you I have no interest in that.

Therefore in your thinking you can certainly hold no weight in measurement of just one unit of a headphone - that means you yourself cannot use most of Oratory's database, neither can you use any of Amir's measurements, neither can you use most of Crinacle's measurements.....I'm glad I'm not you then. The point you are making is irrelevant in this situation, because it's unreasonable to hold an unrealistic bar of say measuring 5+ units of the same headphone to people like Amir / Oratory / Crinacle, etc. You've said your piece, but in reality of the situation, it's meaningless.

 

[paolomo]

The point you are making is irrelevant in this situation, because it's unreasonable to hold an unrealistic bar of say measuring 5+ units of the same headphone

I never said one should be measuring many headphones. I just said averages are meaningless and a different approach is preferable. You keep misconstruing all I write and putting words in my mouth. I understand being defensive about your work but come on. Anyway, I am out of here, I won't bother you any longer with mathematics.

 

[Robbo99999]

I never said one should be measuring many headphones. I just said averages are meaningless and a different approach is preferable. You keep misconstruing all I write and putting words in my mouth. I understand being defensive about your work but come on. Anyway, I am out of here, I won't bother you any longer with mathematics.

If you don't understand my last post as being a logical extension of the point that you are making then you need to "go back to school" / enhance your logical creative thought processes.

EDIT: sorry for the cutting remarks, but I fail to see how you wouldn't see it as a logical extension, I think it's disingenuous that you in fact don't...hence the remarks.

 

[markanini]

I would take the oratory1990 as a base and nudge some octave bands up and down by a 1-2dB until it sounds right. I know oratory is picky about making multiple reseats to capture the true response. The positioning and pressure of the set might differ between you and the artificial ear so don't expect a perfect response just because its an individual measurement.

 

[Robbo99999]

I would take the oratory1990 as a base and nudge some octave bands up and down by a 1-2dB until it sounds right. I know oratory is picky about making multiple reseats to capture the true response. The positioning and pressure of the set might differ between you and the artificial ear so don't expect a perfect response just because its an individual measurement.

Yes, you can follow the advice in his PDA file where it describes at the bottom which filters can be moved to change the sound, on the right side of the following pic:

I haven't really experimented much with that, I should do. Historically I've not needed to tweak away from the Harman Curve, apart from tweaking bass levels or rolling the bass off earlier.....or finding different measurements that sounded more accurate or better. Band 2 & 5, probably Band 5 mostly are the ones that I can envisage making the differences to me that I've not explored much.

 

[Robbo99999]

I can't recall, has he measured a K701 (I have them)

Crinacle has measured the K701, it's very similar to the K702 according to the measurements. I graphed the K702 average of Crinacle & Oratory (which only influences the size of the 5500Hz peak) against your K701:

It's showing that the K701 is a slightly warmer headphone, but sharing many of the same characteristics. It's not too unreasonable to say that the difference could be unit to unit difference or tester difference (even though both done on GRAS).....could be the same headphone model even. However, bass and mids up to 3kHz did match very closely between Crinacle & Oratory when a K702 was measured between the two testers (as seen in following pic), which gives a bit more weight to the above measurement differences.

 

[Robbo99999]

Yes, you can follow the advice in his PDA file where it describes at the bottom which filters can be moved to change the sound, on the right side of the following pic:
View attachment 128129
I haven't really experimented much with that, I should do. Historically I've not needed to tweak away from the Harman Curve, apart from tweaking bass levels or rolling the bass off earlier.....or finding different measurements that sounded more accurate or better. Band 2 & 5, probably Band 5 mostly are the ones that I can envisage making the differences to me that I've not explored much.

I tested altering Band 5 to preference and found it was already spot on at the Harman Curve levels vs my AnechoicEQ'd JBL 308p speakers, but I found the difference was higher up the frequency range, in silibance frequencies and a little below, so Band 9 & 8 in Oratory's EQ, with a little more energy required for me in that area. Given that this is the area where we see differences between Crinacle's & Oratory's measurements (), and that my own EQ based on the average of these two measurements accounts for that then this explains why I prefer my EQ based on an average of the two measurements (,). One little extra difference is my EQ also boosts slightly more between 3-4kHz than Oratory's, which I think is also beneficial for me.

 

[flipflop]

I'm going to propose a different solution to the 5.5 kHz problem.

First, listen to a chirp, such as this, with your unequalized K702:

If you hear a peak between 5 and 6 kHz, base your EQ on Oratory's measurement, if you don't, base it on Crinacle's.
In either case, you should also hear the 2-3 kHz peak. Turn up your volume if you don't. As unpleasant as chirps can be, 5 minutes of testing isn't going to damage your hearing, even at elevated volumes.

 

[Robbo99999]

I'm going to propose a different solution to the 5.5 kHz problem.

First, listen to a chirp, such as this, with your unequalized K702:

If you hear a peak between 5 and 6 kHz, base your EQ on Oratory's measurement, if you don't, base it on Crinacle's.
In either case, you should also hear the 2-3 kHz peak. Turn up your volume if you don't. As unpleasant as chirps can be, 5 minutes of testing isn't going to damage your hearing, even at elevated volumes.

It's a good idea, but it's not that simple. I've listened to sine tone frequency sweeps through the frequency range before, to see if I could identify peaks and I noticed that all my headphones had an absolutely massive peak (increase in volume) from 8500Hz-12200Hz. I spoke with Oratory about this and he said it's probably your ears, and to try the same frequency sweep on my speakers, and low & behold the same massive peak to my ears between 8500Hz-12200Hz.....so my ears are very efficient in this zone and a large increase in volume in that zone should not be equalised down as that is part of my normal hearing. (My JBL 308p speakers are AnechoicEQ'd so that's an accurate reference).

But having said that, I suppose I could do a sine frequency sweep through that area on my speakers and try to work out if my hearing is flat in that area, and if it is then do the same test on my unequalised headphones. I'll put that in the bank and try it out over the next days probably.