[OmniscientNihilist]

I find the sound signature of K361's to be little odd, like it has the clinical sound yet the treble feels little subdued and bass isn't as prevalent, like super dull and thin sound. Came back to them today after many months and didn't like the sound, even prefer my Sony's over them.

thats because there is a huge treble spike at around 8khz

eq that down by about 35%

then it allows the mids and bass to fill in more

 

[ADUHF]

I wonder if there are mods to bring down the upper-mids? I really like the bass on these.

I don't know if you noticed this, but Oratory apparently tried covering the baffle ports on the K371 to see how that might effect the headphone's frequency response. And it appears that doing this lowered the upper mids.

K371 (red) & K371 WITH BAFFLE PORTS CLOSED (blue):

This would probably give the headphones a somewhat warmer tone. But it may also make the peak at around 5-8 kHz stand out a bit more. So it looks like EQ is probably still a better way to go. I guess you could try partially closing the ports though, to see what that does.

THE K371 CURVES ABOVE VS. 3 OTHER NEUTRAL-ISH HEADPHONES:

The regular K371 is in red on this graph, and the K371 with ports closed is in orange. Both of the above plots are compensated with diffuse field compensation btw.

I still think these are probably not constructed well enough to endure the sort regular beating that I put on headphones. So that's why I'm probably leaning a bit more towards the K553 MKII, between the two... if I get another pair of closed AKG's, that is... Which I may or may not.

Both headphones were pretty nicely discounted about a month or so ago. And perhaps I should've snagged a pair of the K553's then. But they are back at around full price again now.

I'm also still waiting to hear more about any new revisions on the K371 (though I've more or less ruled these HPs out for the above reasons).

 

[OmniscientNihilist]

I don't know if you noticed this, but Oratory apparently tried covering the baffle ports on the K371 to see how that might effect the headphone's frequency response. And it appears that doing this lowered the upper mids.

K371 (red) & K371 WITH BAFFLE PORTS CLOSED (blue):



This would probably give the headphones a somewhat warmer tone. But it may also make the peak at around 5-8 kHz stand out a bit more. So it looks like EQ is probably still a better way to go. I guess you could try partially closing the ports though, to see what that does.

THE K371 CURVES ABOVE VS. 3 OTHER NEUTRAL-ISH HEADPHONES:



The regular K371 is in red on this graph, and the K371 with ports closed is in orange. Both of the above plots are compensated with diffuse field compensation btw.

I still think these are probably not constructed well enough to endure the sort regular beating that I put on headphones. So that's why I'm probably leaning a bit more towards the K553 MKII, between the two... if I get another pair of closed AKG's, that is... Which I may or may not.

Both headphones were pretty nicely discounted about a month or so ago. And perhaps I should've snagged a pair of the K553's then. But they are back at around full price again now.

I'm also still waiting to hear more about any new revisions on the K371 (though I've more or less ruled these HPs out for the above reasons).

looks like the 371 have that horrible 8khz peak just like the 361

i had 361 and it has to be lowered by about 35% on the equalizer otherwise the bass and mids sound hollow

 

[ADUHF]

looks like the 371 have that horrible 8khz peak just like the 361

i had 361 and it has to be lowered by about 35% on the equalizer otherwise the bass and mids sound hollow

The peak between 8 and 10 kHz on the K361 was a good find, OmniscientNihilist. Because there really should be more of a notch in that location on Oratory's graphs. If you did not know what to look for there, it's something that could easily be missed.

K371 (red) & K361 (blue) WITH DIFFUSE FIELD COMP:

The design of the K371 and K361 is very similar, which is why their FR plots have alot in common. They use different kinds of drivers and filtering/damping though, so the resonances in the upper mids and treble will be a bit different on the K371 than on the K361.

K371 (red) & K361 (orange) VS. VARIOUS OTHER NEUTRAL-ISH HEADPHONES:

In addition to the bright spot at around 9-10k, it looks like there is also a fairly pronounced bright area between about 700-800 Hz, and 3 kHz on the K361.

 

[markanini]

the K371 to see how that might effect the headphone's frequency response. And it appears that doing this lowered the upper mids.

Wanna hear a 8kHz peak try Beyer DT990. K371 treble is smooth as a baby's bottom by comparison.

 

[ADUHF]

Another plot of the K361 (in orange) that shows the bright spots in the midrange, and treble a little better.

The K371 is also probably a little bright in that same area of the midrange, around roughly 2k. But not to the same extent as the K361. The K361 also appears to have about the same notch or depression at around 4 kHz as the K371.

 

[ADUHF]

Wanna hear a 8kHz peak try Beyer DT990. K371 treble is smooth as a baby's bottom by comparison.

Yes, most of the Beyers are considerably brighter than the K371 in the treble. Sonically, there is really no comparison between the two. The closed-back Beyer DT-770 (250-ohm), and AKG K371 are both fairly well-extended in the bass, and a little too brightly tilted in some places in the upper mids. But that's where most of the similarities end.

 

[Skrilla 009]

Another plot of the K361 (in orange) that shows the bright spots in the midrange, and treble a little better.



The K371 is also probably a little bright in that same area of the midrange, around roughly 2k. But not to the same extent as the K361. The K361 also appears to have about the same notch or depression at around 4 kHz as the K371.

Having owned both k361 and 371, I find myself liking the 371 significantly more despite the supposed slight differences in sound signature. On k361, the combination of treble spike along with subdued lower mids and bass gives it the "hollow" bright sound, even recently listening to them I ended up getting some ear fatigue from high bright it was. 371 does much better with bringing the bass and soundstage, I realized how minor spikes and recession can make a big difference in listening experience imo.

This made me realize I should've went with k371 in the first place, won't be getting my pair back from Warranty until early August anyway

 

[ADUHF]

Having owned both k361 and 371, I find myself liking the 371 significantly more despite the supposed slight differences in sound signature. On k361, the combination of treble spike along with subdued lower mids and bass gives it the "hollow" bright sound, even recently listening to them I ended up getting some ear fatigue from high bright it was. 371 does much better with bringing the bass and soundstage, I realized how minor spikes and recession can make a big difference in listening experience imo.

This made me realize I should've went with k371 in the first place, won't be getting my pair back from Warranty until early August anyway

It's been awhile since I actually listened to these headphones. But to the best of my recollection, the K371 definitely seemed the superior of the two, when played off of Guitar Center's feed. I wasn't totally in love with the K371 though. And still think its response can use some tweaking.

The choice for me probably would've been between the K371 and K553 MkII, which appear to use the same titanium drivers. And I think I would've gone with the latter simply because the design seems a bit more durable. And I already know my way around that headphone well, from using it as my previous daily beater (sans detachable cable).

People's tastes are different though, so I guess I can understand why some might possibly like the K361 better. It just sounded a bit dull and uninteresting to me though by comparison to other two HP's above. (Probably because of that fairly pronounced bump in the upper mids, and the plastic drivers. Though I'm not 100% sure about that.)

The K553 is designed for people with very large heads though. And is rather ugly imo. So I can understand why many might like the K371 better. As long as you are not too rough with them, and they fit well, the K371 might not be such a bad choice. I would use some EQ though with all the above.

Maybe I'd like the K361 with a few tweaks to its frequency response as well. I wish there were more good options though in this price range with decent extension in the bass, and a fairly neutral response across the rest of the frequency range. The open-back Sennheiser HD560s is one HP I've been lookin at a bit lately as a possible alternative. But I haven't had a chance to actually listen to them yet.

 

[Skrilla 009]

It's been awhile since I actually listened to these headphones. But to the best of my recollection, the K371 definitely seemed the superior of the two, when played off of Guitar Center's feed. I wasn't totally in love with the K371 though. And still think its response can use some tweaking.

The choice for me probably would've been between the K371 and K553 MkII, which appear to use the same titanium drivers. And I think I would've gone with the latter simply because the design seems a bit more durable. And I already know my way around that headphone well, from using it as my previous daily beater (sans detachable cable).

People's tastes are different though, so I guess I can understand why some might possibly like the K361 better. It just sounded a bit dull an uninteresting to me though by comparison to other two HP's above. (Probably because of that fairly pronounced bump in the upper mids, and the plastic drivers Though I'm not 100% sure about that.)

The K553 is designed for people with very large heads though. And is rather ugly imo. So I can understand why many might like the K371 better. As long as you are not too rough with them, and they fit well, the K371 might not be such a bad choice. I would use some EQ though with all the above.

Maybe I'd like the K361 with a few tweaks to its frequency response as well. I wish there were more good options though in this price range with decent extension in the bass, and a fairly neutral response across the rest of the frequency range. The open-back Sennheiser HD560s is one HP I've been lookin at a bit lately as a possible alternative. But I haven't had a chance to actually listen to them yet.

From my experience I personally love the K371 (Haven't heard k553 yet), from the charts it seems to be exhibiting the same treble spike but given the bass presence and better mids I guess that distracted me away from the spike, unlike with k361 from the hollowed sound. From now I just hope my 2nd pair of k371 lasts me, seems like the design feels flimsy and sensitive, which I might have to invest in a headphone stand.

 

[klogg4]

You know what? Screw all the equalization, K371 is the best closed-back headphone that I had ever heard. Absolutely epic cans.

The only thing I dislike is upper mids (don't think it's FR related, more like distortion). Maybe midbass is a little like not enough. But other closed backs have much more drawbacks than these.

 

[Kammerat Rebekka]

I’ve been watching this thread now and again and see this ‘upper-mids’ issue pop up from time to time…and it doesn’t really make sense…especially when you see that some of these comments come from peeps that both own and adore a Sennheiser HD600/650..which is even more forward in the presence region.
The K371 is about the most linear closedback headphone you can find on the market these days, regardless of pricetag. What it does have is a slight edge in the treble..but slight being the keyword there. It’s not a DT770 that will take your head off with cymbal crashes from hell.
Also…AKG has managed to overcome most of the common downsides to closedback headphones. All closedbacks surfer from a lack of realism to my ears. There’s a ‘cuppiness’ and unnatural vacuum-like feeling to the presentation that most often make me reach for an openback…but over the K371 it’s not as bad. The presentation still sounds about as right as I’ve tried over a closedback..AND the midrange doesn’t fall off a cliff.

I gather the squiggles are due to the pads that used to come crinkled from the factory. With the new ones that is not the case.
But yeah…the above is worldclass..regardless of design..but when you add on the fact that it’s a closed coconut…well it sorta puts things into perspective.
Price tag and sound quality does not pertain to one another…even if most of this site hawks that view. It’s nonsense, pure and simple.

 

[MayaTlab]

I’ve been watching this thread now and again and see this ‘upper-mids’ issue pop up from time to time…and it doesn’t really make sense…especially when you see that some of these comments come from peeps that both own and adore a Sennheiser HD600/650..which is even more forward in the presence region.
The K371 is about the most linear closedback headphone you can find on the market these days, regardless of pricetag. What it does have is a slight edge in treble..but slight being the keyword there. It’s not a DT770 that will take your head off with cymbal crashes from hell.
Also…AKG has managed to overcome most of the common downsides to closedback headphones. All closedbacks surfer from a lack of realism to my ears. There’s a ‘cuppiness’ and unnatural vacuum-like feeling to the presentation that most often make me reach for an openback…but over the K371 it’s not as bad. The presentation still sounds about as right as I’ve tried over a closedback..AND the midrange doesn’t fall off a cliff.

I gather the squiggles are due to the pads that used to come crinkled from the factory. With the new ones that is not the case.

Responding to the bolded sections above.

I've had two pairs of the "properly packaged" version (as the first's right earcup stopped working) and both continue to show a fairly wiggly response at lower frequencies with not superb L/R matching. The main difference for me is while the "crumpled pads" samples would fail to effectively seal in all situations, the "not crumpled pads" versions manage to provide a decent seal on my head... as long as I look forward and don't lean my head in any direction whatsoever.

Below is a measurements of the K371's L (teal) and R (blue) channels on my own head (so use only the examples below as an illustration of what COULD happen on a real human's head - the same methodology and tools may give different results on your own head) with these mics : https://www.soundprofessionals.com/cgi-bin/gold/item/MS-TFB-2
I can calibrate them with my speakers against a UMIK-1 but they're already pretty well matched with it in the range of interest I can assess (I have no way of knowing whether or not they match below 50-60Hz as my speakers don't go any lower).
The dotted blue line represents the K371's right channel when I slightly lean forward (by slightly I mean "look at my computer on the table", not 90°).
The two traces above are the AirPods Max' L and R channels. Because of the APM's ANC circuit it can deliver an exact FR below a few hundred hertz regardless of pad compression / seal quality / etc. (well, as long as we don't look at edge cases - the APM's compromised headband to cup attachment makes it break seal on my head when I significantly rotate it left / right, but for every day life it's not too bad), and so far the several APMs I've measured on my own head show very little sample variation and good channel matching (very much unlike the K371).

Don't look at the wiggles below 60Hz, it's just that I didn't run sweeps at a loud enough volume and long enough duration. Above that they're valid.
Also, don't look at the absolute values below 50-70Hz, as I wrote I have no way of checking whether they're somewhat correct or not, only look at relative comparisons in that range.

So the TLDR is that while the K371's FR at lower frequencies is quite an achievement in terms of linearity compared to most other closed backs, particularly at its price point, it's still not quite excellent, and at least as far as I'm concerned (as it depends a lot on the listener's anatomy), it's quite inconsistent in terms of seal quality (and I'd like to add that it's also highly inconsistent from seatings to seatings to the point where even several averages of five measurements will still exhibit differences).

I would not be surprised that the instability at lower frequencies is something that most people would actually experience with most closed backs, at least to some degree.

In regards to what happens above 1kHz on my own head still, it's quite a bit more difficult to assess and I'm not quite as confident about the way I can measure them.

I can use this amateurish experimental DIY protraction : https://www.head-fi.org/threads/how...guarantee-a-better-sound.958201/post-16405751.
I'm actually underselling it as for headphones with low seatings variations I have the feeling that it's pretty darned precise for relative comparisons up to around 10kHz or so (something I'm in the process of trying to confirm at least up to 7kHz or so with measurements at the canal's entry with regular electret mics).
The main problem being that the K371 is not one of these headphones with low seatings variations. In fact for me it's the one that gives me by far the most inconsistent results from seatings to seatings, not just below 1kHz, but across the entire range I can assess to some degree.

So, while I have quite a few concerns that my measurements of the K371 (and to a lesser degree my APMs) are not quite as reliable as, let's say, the measurements I've made so far with this process with my HD650, HD560S, Hi-X65, Sundara or HE-400SE, here they are :

In solid red the APM's right channel, in solid blue the K371's right channel, in solid green as a reference the HD650 with somewhat fresh, but broken in pads.
These were made during the same measurement session, ie the probe wasn't moved (something I can easily check by peppering the session with regular measurements of a pair of headphones with low seatings variation). Cf. link above to see the typical variation across different sessions and why that isn't so much of a concern for relative comparisons.
Important note that's worth repeating : these results are not valid for you, they just illustrate my own experience of my own samples on my own head. Also, don't look at the absolute values, they're necessarily incorrect to some degree, only look at the relative values between headphones.
And don't take it quite literally. I can't use these measurements to assert that at 8769Hz headphones A is 3,76dB higher than headphones B. More like "at around 6200Hz, headphones A tends to be 3-4 dB higher than headphones B". Particularly for the K371 for which I feel that I'm living in a 2-3dB tolerance land above 5-6kHz or so, and to a lesser extent the APM.
Finally, mind the scale on the left hand side. Each line is 0.5dB appart.

So with my own samples, on my head, the HD650 isn't wholly more forward than the K371, and - surprisingly given the measurements of it I've seen online, but not so surprising given my own listening tests - the APM is not quite so far appart from both (albeit a small dB difference across a wide bandwidth is noticeable, so it's still overall quite a bit depressed relative to the HD650 in the ear canal gain region).
The K371 exhibits somewhat of a null at around 3800-4000Hz (this one actually shifts across seatings), consistent with some measurements I've seen online.
Above 4kHz it's a bit of a peaky mess (confirmed with listening tests) and I personally find it a bit fatiguing. But again it's quite inconsistent.

I added two dotted traces in blue and and red which represent the K371's and APM's response respectively when the cups are slightly compressed against my head to re-balance the pressure around my ear (both headphones suffer from a poor headband to cup attachment design that makes them press unevenly around my ears). In both cases this results in a fairly significant difference, particularly in the ear canal gain region, at least below 3kHz or so. In the case of the APM it also solves a null at around 5800Hz. While this is not something I can be certain of, I'd draw the hypothesis that the APM's generally depressed ear canal gain region on test rigs measurements - particularly the ones that don't replicate a full human head -, and the K371's inconsistent results in the same area on said test rigs, may partially come from the rigs' design around the artificial pinna not interacting with the headphones' mechanical design in a realistic way (https://crinacle.com/2020/12/19/apple-airpods-max-review-the-audiophiles-perspective/).

I find these results quite interesting in light of that post from Jude : https://www.head-fi.org/threads/sen...ments-harman-target-talk.957709/post-16346549
Quoting : "Compared to the AKG K371 (which is one of the closest matches to the Harman AE/OE Target), I find the AirPods Max to have more neutral sounding midband and treble. I understand some will agree and some will disagree, but that's part of the point I was making in the video."
I share Jude's assessment and also prefer the APM, but maybe - just maybe - it's because, at least in my own case, on my own head, it's the one that actually tracks Harman's target better (or at least its intent) ? It's not something that I can actually know. Which one of the three above is the most representative of the target ? Impossible to assess without going to Harman's own listening room and measuring their speakers on my own head with the contraption above I suppose ?

Anyway, TLDR : dummy head / test rigs measurements are a great way to start to characterise headphones, and in these tests the K371 is a great achievement among closed backs, but some deviation from third party measurements will happen on your own head and the K371 may not shine quite as well in these conditions than other closed backs, and the results may not wholly conform to what you'd expect looking at these measurements.
TLDR 2 : while I can't speak about what others would experience, for me there is at least another pair of closed backs that's more linear than the K371, with the added benefit of being way more consistent, particularly below 800Hz or so. While I don't particularly love the way both the K371 and APM sound, the latter is IMO, for me, a much better basis for PEQ than the former (or any other closed back I've ever tried for that matter).

 

[markanini]

You know what? Screw all the equalization, K371 is the best closed-back headphone that I had ever heard. Absolutely epic cans.

The only thing I dislike is upper mids (don't think it's FR related, more like distortion). Maybe midbass is a little like not enough. But other closed backs have much more drawbacks than these.

My theory is that it's not that the upper mids are too hot, its that the mid-bass is recessed. Try cutting 250Hz on the HD6XX and you will hear something similar.

 

[Kammerat Rebekka]

Responding to the bolded sections above.

I've had two pairs of the "properly packaged" version (as the first's right earcup stopped working) and both continue to show a fairly wiggly response at lower frequencies with not superb L/R matching. The main difference for me is while the "crumpled pads" samples would fail to effectively seal in all situations, the "not crumpled pads" versions manage to provide a decent seal on my head... as long as I look forward and don't lean my head in any direction whatsoever.

Below is a measurements of the K371's L (teal) and R (blue) channels on my own head (so use only the examples below as an illustration of what COULD happen on a real human's head - the same methodology and tools may give different results on your own head) with these mics : https://www.soundprofessionals.com/cgi-bin/gold/item/MS-TFB-2
I can calibrate them with my speakers against a UMIK-1 but they're already pretty well matched with it in the range of interest I can assess (I have no way of knowing whether or not they match below 50-60Hz as my speakers don't go any lower).
The dotted blue line represents the K371's right channel when I slightly lean forward (by slightly I mean "look at my computer on the table", not 90°).
The two traces above are the AirPods Max' L and R channels. Because of the APM's ANC circuit it can deliver an exact FR below a few hundred hertz regardless of pad compression / seal quality / etc. (well, as long as we don't look at edge cases - the APM's compromised headband to cup attachment makes it break seal on my head when I significantly rotate it left / right, but for every day life it's not too bad), and so far the several APMs I've measured on my own head show very little sample variation and good channel matching (very much unlike the K371).

Don't look at the wiggles below 60Hz, it's just that I didn't run sweeps at a loud enough volume and long enough duration. Above that they're valid.
Also, don't look at the absolute values below 50-70Hz, as I wrote I have no way of checking whether they're somewhat correct or not, only look at relative comparisons in that range.

So the TLDR is that while the K371's FR at lower frequencies is quite an achievement in terms of linearity compared to most other closed backs, particularly at its price point, it's still not quite excellent, and at least as far as I'm concerned (as it depends a lot on the listener's anatomy), it's quite inconsistent in terms of seal quality (and I'd like to add that it's also highly inconsistent from seatings to seatings to the point where even several averages of five measurements will still exhibit differences).

I would not be surprised that the instability at lower frequencies is something that most people would actually experience with most closed backs, at least to some degree.

In regards to what happens above 1kHz on my own head still, it's quite a bit more difficult to assess and I'm not quite as confident about the way I can measure them.

I can use this amateurish experimental DIY protraction : https://www.head-fi.org/threads/how...guarantee-a-better-sound.958201/post-16405751.
I'm actually underselling it as for headphones with low seatings variations I have the feeling that it's pretty darned precise for relative comparisons up to around 10kHz or so (something I'm in the process of trying to confirm at least up to 7kHz or so with measurements at the canal's entry with regular electret mics).
The main problem being that the K371 is not one of these headphones with low seatings variations. In fact for me it's the one that gives me by far the most inconsistent results from seatings to seatings, not just below 1kHz, but across the entire range I can assess to some degree.

So, while I have quite a few concerns that my measurements of the K371 (and to a lesser degree my APMs) are not quite as reliable as, let's say, the measurements I've made so far with this process with my HD650, HD560S, Hi-X65, Sundara or HE-400SE, here they are :

In solid red the APM's right channel, in solid blue the K371's right channel, in solid green as a reference the HD650 with somewhat fresh, but broken in pads.
These were made during the same measurement session, ie the probe wasn't moved (something I can easily check by peppering the session with regular measurements of a pair of headphones with low seatings variation). Cf. link above to see the typical variation across different sessions and why that isn't so much of a concern for relative comparisons.
Important note that's worth repeating : these results are not valid for you, they just illustrate my own experience of my own samples on my own head. Also, don't look at the absolute values, they're necessarily incorrect to some degree, only look at the relative values between headphones.
And don't take it quite literally. I can't use these measurements to assert that at 8769Hz headphones A is 3,76dB higher than headphones B. More like "at around 6200Hz, headphones A tends to be 3-4 dB higher than headphones B". Particularly for the K371 for which I feel that I'm living in a 2-3dB tolerance land above 5-6kHz or so, and to a lesser extent the APM.
Finally, mind the scale on the left hand side. Each line is 0.5dB appart.

So with my own samples, on my head, the HD650 isn't wholly more forward than the K371, and - surprisingly given the measurements of it I've seen online, but not so surprising given my own listening tests - the APM is not quite so far appart from both (albeit a small dB difference across a wide bandwidth is noticeable, so it's still overall quite a bit depressed relative to the HD650 in the ear canal gain region).
The K371 exhibits somewhat of a null at around 3800-4000Hz (this one actually shifts across seatings), consistent with some measurements I've seen online.
Above 4kHz it's a bit of a peaky mess (confirmed with listening tests) and I personally find it a bit fatiguing. But again it's quite inconsistent.

I added two dotted traces in blue and and red which represent the K371's and APM's response respectively when the cups are slightly compressed against my head to re-balance the pressure around my ear (both headphones suffer from a poor headband to cup attachment design that makes them press unevenly around my ears). In both cases this results in a fairly significant difference, particularly in the ear canal gain region, at least below 3kHz or so. In the case of the APM it also solves a null at around 5800Hz. While this is not something I can be certain of, I'd draw the hypothesis that the APM's generally depressed ear canal gain region on test rigs measurements - particularly the ones that don't replicate a full human head -, and the K371's inconsistent results in the same area on said test rigs, may partially come from the rigs' design around the artificial pinna not interacting with the headphones' mechanical design in a realistic way (https://crinacle.com/2020/12/19/apple-airpods-max-review-the-audiophiles-perspective/).

I find these results quite interesting in light of that post from Jude : https://www.head-fi.org/threads/sen...ments-harman-target-talk.957709/post-16346549
Quoting : "Compared to the AKG K371 (which is one of the closest matches to the Harman AE/OE Target), I find the AirPods Max to have more neutral sounding midband and treble. I understand some will agree and some will disagree, but that's part of the point I was making in the video."
I share Jude's assessment and also prefer the APM, but maybe - just maybe - it's because, at least in my own case, on my own head, it's the one that actually tracks Harman's target better (or at least its intent) ? It's not something that I can actually know. Which one of the three above is the most representative of the target ? Impossible to assess without going to Harman's own listening room and measuring their speakers on my own head with the contraption above I suppose ?

Anyway, TLDR : dummy head / test rigs measurements are a great way to start to characterise headphones, and in these tests the K371 is a great achievement among closed backs, but some deviation from third party measurements will happen on your own head and the K371 may not shine quite as well in these conditions than other closed backs, and the results may not wholly conform to what you'd expect looking at these measurements.
TLDR 2 : while I can't speak about what others would experience, for me there is at least another pair of closed backs that's more linear than the K371, with the added benefit of being way more consistent, particularly below 800Hz or so. While I don't particularly love the way both the K371 and APM sound, the latter is IMO, for me, a much better basis for PEQ than the former (or any other closed back I've ever tried for that matter).

That’s a whole lot of text to underscore the fact that we all hear differently and that headphone measurements only are half the story
..but I very much agree with you..and I’m glad that you have found a great closedback in the Apple offering. I personally prefer the sound and comfort of the AKG but must admit to being positively surprised by the presentation from the Apple.