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Does this graph look correct for a AKG K240 DF? Only my 2nd attempt!

Gadget Goober

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Howdy folks! I'm so glad I found this forum, holy heck. This is my first post and I'm stoked to "feel" that this forum is finally a judgement-free area. I was sort of hesitant to join other forums, and ended up not doing so because I'm relatively new to this world, as compared with the seasoned pros (or those that pass themselves on as season pros, anyway!). However, when it comes to electronics, etc, I'm experienced, as needed for my line of work, so.... I can learn!

Anyway, I've been messing around with my new ears on a stand from MiniDSP, and trying to take some measurements on REW -

My 2nd attempt so far - am I doing this right?

I've attempted to graph my new-to-me AKG K240df cans, as I bought them used and wanted to ensure the drivers were original. I always hear that the K240df was "flat", so I figured it would be a good set of cans to measure on REW, because I could expect a certain result, if that makes sense.

Could someone please kindly take a peek at these graphs and tell me if I'm on the right track? I sort of expected a flatter response - am I mistaken?
(There's two, one for each calibration file for headphones that came with the ears - I haven't tried RAW yet)

Cheers and thanks!
 

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solderdude

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I would try to measure some well documented headphones instead of a not well documented headphone where there are little reliable plots from.

Also do you use the compensation from miniDSP (which is incorrect) or the one from SBAF ?
 
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Gadget Goober

Gadget Goober

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That sounds like great advice - I have a collection of over 50 cans so that shouldn't be an issue. Perhaps the portapros would suffice.
Also, I'm using miniDSP's compensation - the super best audio friends one, I don't have. I'll go search for it, though!
 

solderdude

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The Portapro's are very ear shape dependent as they are on-ears. Also the foam on these headphones decays quickly changing the sound as well.
Perhaps a well known over-ear would be best to get a baseline.
All test rigs measure similar headphones differently. Not one of them is correct. Some are closer to reality than others though.
Also take seal into account as well as pad-wear and unit to unit variance.
 
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Gadget Goober

Gadget Goober

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Thanks for the advice. I went to pop them on, and realized exactly what you described - I'll just use my HD6xx's, that seems like the best bet.

I found the SBAF compensation list - boy, that's gonna be an easy but tedious task, adding all those values, but I'll work on it over time - I'm sure it'll be worth it.

Maybe I should come up with a spreadsheet that can convert the values automatically and share it...
 

3125b

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Even for a flat plate measurement, that doesn't look right. The K240 DF supposedly has a diffuse field tuning (hence the name), though the only other measurement (innerfidelity: AutoEq/results/innerfidelity/innerfidelity_harman_over-ear_2018/AKG K240DF at master · jaakkopasanen/AutoEq · GitHub) I've seen shows it to have almost exactly a free field tuning.
Whatever the case, as solderdude said, it's an obscure headphone from a long time ago in Germany, let alone in the US.

I'll just use my HD6xx's, that seems like the best bet.
It's a safe choice.
Overear with large cups and non-angled drivers seem easiest to set up. Always check for seal of course, though open back headphones with velours pads are generally less susceptible to FR changes with a broken seal. And be careful about pads, different pads, even if they generally look and feel similar to the originals, can have a very profound impact.
 
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Gadget Goober

Gadget Goober

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Even for a flat plate measurement, that doesn't look right. The K240 DF supposedly has a diffuse field tuning (hence the name), though the only other measurement (innerfidelity: AutoEq/results/innerfidelity/innerfidelity_harman_over-ear_2018/AKG K240DF at master · jaakkopasanen/AutoEq · GitHub) I've seen shows it to have almost exactly a free field tuning.
Whatever the case, as solderdude said, it's an obscure headphone from a long time ago in Germany, let alone in the US.


It's a safe choice.
Overear with large cups and non-angled drivers seem easiest to set up. Always check for seal of course, though open back headphones with velours pads are generally less susceptible to FR changes with a broken seal. And be careful about pads, different pads, even if they generally look and feel similar to the originals, can have a very profound impact.


3125b, I highly appreciate the feedback! I just got done with the SBAF compensation, I added the values to my miniDSP provided values and I'm going to take a look at what the 6xx's look like in just a few. I took a look at the graphs you provided, they don't look anything like what I expected... I expected a very flat graph, but... after research - I think I now understand better what is meant by diffuse field...

Please correct me if I'm wrong - in a nutshell, the aim of the diffuse field target, in an over-ear headphone or IEM, is to reproduce a flat response (dB SPL vs Freq) at the "eardrum", let's say, AFTER it is "compensated" by the pinnae and canal, etc. - Am I on the right track in learning here? In other words, if the dB SPL vs frequency was flat coming out of the cans, by the time it would reach your eardrum, it wouldn't be flat any longer. Seems so obvious, and if I'm right, I can't believe I didn't realize this going in. Shame on me!

Can't thank y'all enough! Loving this forum so far, can't wait to dive in further.
 

solderdude

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Please correct me if I'm wrong - in a nutshell, the aim of the diffuse field target, in an over-ear headphone or IEM, is to reproduce a flat response (dB SPL vs Freq) at the "eardrum", let's say, AFTER it is "compensated" by the pinnae and canal, etc.

Diffuse field 'target' is a measurement method for calibrating a HATS where several speaker sources are used all around the HATS.
What is measured is the frequency response at the mic (somewhat close to an eardrum) under these conditions.

These conditions vary a lot from IEM's and headphones. By lack of anything better most measuring folks used DF or even worse compensations.

Currently there is more attention for test fixtures for headphones. In all cases they are not 'correct' but some do better in certain areas than others.
 

dougi

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Even for a flat plate measurement, that doesn't look right. The K240 DF supposedly has a diffuse field tuning (hence the name), though the only other measurement (innerfidelity: AutoEq/results/innerfidelity/innerfidelity_harman_over-ear_2018/AKG K240DF at master · jaakkopasanen/AutoEq · GitHub) I've seen shows it to have almost exactly a free field tuning.
Whatever the case, as solderdude said, it's an obscure headphone from a long time ago in Germany, let alone in the US.


It's a safe choice.
Overear with large cups and non-angled drivers seem easiest to set up. Always check for seal of course, though open back headphones with velours pads are generally less susceptible to FR changes with a broken seal. And be careful about pads, different pads, even if they generally look and feel similar to the originals, can have a very profound impact.
Obscure? I have a pair from new, early 1990s. Bought from local hifi store. New dekoni pads last year and they have never sounded better. Certainly seal better now. Certainly different than before. More bass.
 
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Gadget Goober

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I have to admit, they do sound freaking amazing. It's honestly giving my 6XX's a run for their money. I find myself reaching for them lately. A surprising set of on-ears that sound surprisingly fantastic to me are my Sonic Pro 26's. Those were a huge shock. I never expected for them to end up being one of my favorites out my 100+ collection, and to me they sound leagues better than the Pioneer SE-40L's they're "emulating". I'm pretty good in the history and enthusiast knowledge on cans and IEMs, but when it comes to graphs and analysis, I'm sorely lacking. I knew the history on the k240DFs, but the diffuse field concept is new to me - this is a big reason why I bought it, to become acquainted first hand.

To be frank, I'd like to review my collection one by one online someday soon (for fun, here and elsewhere) and do maybe a subjective (of course) tournament style showdown over the course of a few months and end up with the one I think sounds best to me, with a teardown for each, and possible conversion to balanced for each one that could benefit from it (almost exclusively for a higher potential volume level on portable devices like my Fiio M11), for the amateurs and enthusiasts like me. I found it tricky to break into the analytical side of this hobby somewhat, for the feel that there's a lot of holier-than-thou mediums that don't lend well to entry-level analytical endeavors like mine. That's a euphemism. Would like to share my journey, little by little with others like me. But, I'd also like to introduce a tiny few objective factors too. And for this, I need to study and be sure I know what I'm presenting, open to criticism and input from audience, which will be enthusiast level at best... admittedly.

I'm gathering more knowledge on diffuse field concepts now, I think I see now that it still seems rather nebulous in regards to the various setups, etc. LOL :D Continuing my research until I can fully grasp it.

Currently working on a teardown, cleaning and restoration of many pairs of my cans. My aim with the graphs is to see, for fun, how the graph changed after my teardown. Namely, replacing foams, pads, etc.

I have a lot of studying to do! but I've given up the other hobby (vehicle restoration), and have sold a good chunk of all my cars to focus on this. Will sell them all soon.

Again, very glad to be here. Thanks folks.
 
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SpaceMonkey

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Obscure? I have a pair from new, early 1990s. Bought from local hifi store. New dekoni pads last year and they have never sounded better. Certainly seal better now. Certainly different than before. More bass.
Which dekoni did you get? I use my k240s with akg velour pads. Might be less bass but easier fitting on the ear.
 

dougi

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Which dekoni did you get? I use my k240s with akg velour pads. Might be less bass but easier fitting on the ear.
Premium pleather or the like I think. Old foam had stuck to the driver covers, which meant I also had to scrape off the paper stuff. Replaced with medical paper sticky be tape which looked identical
 

Blank Verse

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I have to admit, they do sound freaking amazing. It's honestly giving my 6XX's a run for their money. I find myself reaching for them lately. A surprising set of on-ears that sound surprisingly fantastic to me are my Sonic Pro 26's. Those were a huge shock. I never expected for them to end up being one of my favorites out my 100+ collection, and to me they sound leagues better than the Pioneer SE-40L's they're "emulating". I'm pretty good in the history and enthusiast knowledge on cans and IEMs, but when it comes to graphs and analysis, I'm sorely lacking. I knew the history on the k240DFs, but the diffuse field concept is new to me - this is a big reason why I bought it, to become acquainted first hand.

To be frank, I'd like to review my collection one by one online someday soon (for fun, here and elsewhere) and do maybe a subjective (of course) tournament style showdown over the course of a few months and end up with the one I think sounds best to me, with a teardown for each, and possible conversion to balanced for each one that could benefit from it (almost exclusively for a higher potential volume level on portable devices like my Fiio M11), for the amateurs and enthusiasts like me. I found it tricky to break into the analytical side of this hobby somewhat, for the feel that there's a lot of holier-than-thou mediums that don't lend well to entry-level analytical endeavors like mine. That's a euphemism. Would like to share my journey, little by little with others like me. But, I'd also like to introduce a tiny few objective factors too. And for this, I need to study and be sure I know what I'm presenting, open to criticism and input from audience, which will be enthusiast level at best... admittedly.

I'm gathering more knowledge on diffuse field concepts now, I think I see now that it still seems rather nebulous in regards to the various setups, etc. LOL :D Continuing my research until I can fully grasp it.

Currently working on a teardown, cleaning and restoration of many pairs of my cans. My aim with the graphs is to see, for fun, how the graph changed after my teardown. Namely, replacing foams, pads, etc.

I have a lot of studying to do! but I've given up the other hobby (vehicle restoration), and have sold a good chunk of all my cars to focus on this. Will sell them all soon.

Again, very glad to be here. Thanks folks.
Do you have a set of K240 Monitors (600 ohm, Austrian) to compare your K240DF to? Some people claim the main difference between them is a bass port that is covered in the case of the K240DF, though I think the drivers are also more closely matched.

Even if reviewing your full collection sounds daunting, you might want to start by posting your lineup here: https://www.audiosciencereview.com/forum/index.php?threads/what-headphone-s-do-you-own.4285/
 

SpaceMonkey

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Do you have a set of K240 Monitors (600 ohm, Austrian) to compare your K240DF to? Some people claim the main difference between them is a bass port that is covered in the case of the K240DF, though I think the drivers are also more closely matched.

Even if reviewing your full collection sounds daunting, you might want to start by posting your lineup here: https://www.audiosciencereview.com/forum/index.php?threads/what-headphone-s-do-you-own.4285/
I didnt do measurements but have both 240df and 240m . 240m has a bit more bass and 240df feels a bit more sibilant.
 
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