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AKG K240 55 Ohm Review (Headphone)

solderdude

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A: It depends on what is played through the monitor.
B: It depends on how loud it is and what the surrounding noises are.
C: It depends on how familiar one is with the headphone.
D: It depends on how much 'quality' the musicians want (most don't give a crap about sound quality)
E: It depends on whether or not the recording engineers apply some EQ if needed
F: If one wants 'accurate' the K361 is affordable but certainly not a sturdy workhorse.
G: A musician may want to turn up his monitor louder but it is not him that decides how the recording sounds.

In most studios the monitoring headphones are not 'accurate' hifi phones but the usual suspects (Sony, Beyer, AKG, Sennheiser).
And these are the workhorses (the ones you can sit on, throw on the floor etc not hifi phones)
On the mixing consoles some headphones are either EQ'ed or higher quality.
Serious recordings are not mixed on headphones alone.

Music enjoyment and studio work require different headphones for various reasons.
 

markanini

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I wish there was some solid data on what different headphone responses do to performers in a tracking situation. From my own experience volume is the most important feature. Isolation could be a means to a similar end.
 

PuX

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I'd like to point out that K701 and Q701 are very different (drivers and tuning).

K701 and K702 are almost the same except the color and detachable cable, although the anniversary version might be different, same goes for models made in different countries (Austria vs China).

K712 are very different (pads, driver, tuning) and there could be differences between pairs made in Austria vs Slovakia.
also I bought my K712 for ~$210-220, even though the official MSRP is $575, and price does not really translate well into quality of sound anyway.

K240S do sound sort of dull like Amir described (I own a pair of these as well).
 

DarrylG

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I have these in the form of the Massdrop M220 Pro. It's a shame they sound so "blah". A lot of user-replaceable parts are available for it.

 

Maiky76

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This is a review and detailed measurements of the AKG K240 55 ohm Semi-Open, "Professional Studio" Headphones. It is on kind loan from a member and costs US $69 from Amazon including Prime shipping.

Note: our company, Madrona Digital carries Harman products. AKG is owned by Harman so feel free to read as much bias as you feel necessary into this review.

The K240 has a kind of retro "aviator" look to it:

View attachment 135165

The sample I have has thicker velour pads as you see. Owner was kind enough to also supply the original, thin pads but they were severely degraded so I did not use them. There were also a couple of filters included. I am not sure if they were part of the original design and not used when the pads were swapped or what. No, I am not going to measure this headphone twice. Not everything needs to be a science a project. :)

These are very light headphones owing to thin plastics used:

View attachment 135167

During playback I could feel the entire cup resonating with each note.

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

Fitting these headphones on the fixture was a challenge at first as the headband was simply too large. The cups would not remotely seal. After squeezing every bit of adjustment it allowed, I managed to get 90% or better seal. Looking at other measurements, seems like correlation is high so I went with it.

AKG K240 55 Ohm Measurements
As usual we start with our frequency response:

View attachment 135168

Every time I measure a headphone I hope to see something close to target, I get disappointed most of the time and this is no exception. Besides the bass roll off we also have shortfall in the critical region of 1 to 2 kHz which establishes how "open" a headphone sounds. There is also some lack of treble energy around 4 to 5 kHz with a bit of peaking around 8 kHz. Overall I expect this headphone to sound quite "unexciting." But we shall see. Here is the deviation from our target:

View attachment 135169

Deviation from target response is one thing but what's up with this?

View attachment 135170

View attachment 135171

Group delay indicates some interference pattern but that is common:
View attachment 135172

Sensitivity is a bit below average:

View attachment 135173


Impedance is stated at 55 ohm but it rises to three times as much in lower frequencies, and double that at highest:

View attachment 135174

AKG K240 Listening Tests and Equalization
I could not listen to the stock sound of this headphone for more than a few seconds. It is deeply compressed and dull sounding with a bit of ting once in a one. Equalization is absolutely mandatory for good sound. I developed one quickly by eye. A more proper one requires some automation or more work:

View attachment 135175

This gave the headphone much more life with better bass, mid-range and treble response.

Spatial qualities were non-existent and didn't develop with EQ but the sound was more open.

Conclusions
Please pardon me for being crude but if I had to listen to these headphones without EQ, I would give up on being an audiophile! None of my reference tracks sounded exciting with this headphone and many of these tracks are picked because they tend to sound good on many gear! What business does AKG have to call these "Professional Studio" headphones? What possible asset do they bring to pro world? Technically there is nothing you can hang your hat on here. How it gets more than 7,000 reviews on Amazon averaging 4.5 stars is beyond me. I don't care how cheap a headphone is. It needs to be bring a minimum level of fidelity and this headphone does not.

I can not recommend the AKG K240 55 ohm. If you are stuck with it, be sure to use equalization to breath some much needed life into it.

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

Appreciate any donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

Here are some thoughts about the EQ.

Notes about the EQ design:
  • The average L/R is used to calculate the score.
  • The resolution is 12 points per octave interpolated from the raw data (provided by @amirm)
  • A Genetic Algorithm is used to optimize the EQ.
  • The EQ Score is designed to MAXIMIZE the Score WHILE fitting the Harman target curve with a fixed complexity.
    This will avoid weird results if one only optimizes for the Score.
    It will probably flatten the Error regression doing so, the tonal balance should be more neutral.
  • The EQs are starting point and may require tuning (certainly at LF).
  • The range above 10kHz is usually not EQed unless smooth enough to do so.
  • I am using PEQ (PK) as from my experience the definition is more consistent across different DSP/platform implementations than shelves.
  • With some HP/amp combo the boosts and preamp gain need to be carefully considered to avoid issues
Good L/R match.

I have generated one EQ, the APO config file is attached.

Score no EQ: 73.4
Score Armirm: 92.4
Score with EQ: 94.9


Code:
AKG K240 APO EQ -1.5dB@HF 96000Hz
June152021-095241

Preamp: -9.4 dB

Filter 1: ON PK Fc 29 Hz Gain 9.4 dB Q 0.68
Filter 2: ON PK Fc 216 Hz Gain -2.7 dB Q 0.88
Filter 3: ON PK Fc 1695 Hz Gain 7.2 dB Q 1.96
Filter 4: ON PK Fc 2597 Hz Gain -1.95 dB Q 4.58
Filter 5: ON PK Fc 4704 Hz Gain 8 dB Q 4.35
Filter 6: ON PK Fc 7789 Hz Gain -7 dB Q 4

AKG K240 Dashboard.png
 

Attachments

  • AKG K240 APO EQ -1.5dB@HF 96000Hz.txt
    340 bytes · Views: 117

B4ICU

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I wonder if Amir backs up some of the claims, members posted, regarding non relevant data above 10kHz?
As if so, why would it be published? I would expect to have a plot from 20Hz to 10kHz only. Anything above 10kHz should be irrelevant.
I would like to remind the readers, that the Hi-Fi values to stand in line with a Hi-Fi product definition, it only need to stand in line of no
less than -3dB drop ref. to the 1kHz level, from 20Hz to 20kHz. That is 1/2 amplitude or SPL (50%),
In plain language, a -20dB drop (as on some recent tests on HP) is 1/100! or in other words, it's level is only 1% of what it is at the ref. Fr.
This is not acceptable, even an EQ won't help you out on this.
Something seems to not work properly in the HP kingdome.
 

Bruce Morgen

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Thanks for this, Amir -- I almost bought a pair based on long positive experience with AKG products. No chance of that now. :(
 

solderdude

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I wonder if Amir backs up some of the claims, members posted, regarding non relevant data above 10kHz?
As if so, why would it be published? I would expect to have a plot from 20Hz to 10kHz only. Anything above 10kHz should be irrelevant.
I would like to remind the readers, that the Hi-Fi values to stand in line with a Hi-Fi product definition, it only need to stand in line of no
less than -3dB drop ref. to the 1kHz level, from 20Hz to 20kHz. That is 1/2 amplitude or SPL (50%),
In plain language, a -20dB drop (as on some recent tests on HP) is 1/100! or in other words, it's level is only 1% of what it is at the ref. Fr.
This is not acceptable, even an EQ won't help you out on this.
Something seems to not work properly in the HP kingdome.

Why do you refuse to use the thread purposely created for complaints about the measurement methods ?
 

bennybbbx

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thats the typical AKG sound. few bass and much 8 khz. around 9-10 years ago i have a akg 514 2 buy. very simular FR . for short hearing time sound good but when longer hear the 8 khz boost give pain on ears.
.
 

Robbo99999

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Here are some thoughts about the EQ.

Notes about the EQ design:
  • The average L/R is used to calculate the score.
  • The resolution is 12 points per octave interpolated from the raw data (provided by @amirm)
  • A Genetic Algorithm is used to optimize the EQ.
  • The EQ Score is designed to MAXIMIZE the Score WHILE fitting the Harman target curve with a fixed complexity.
    This will avoid weird results if one only optimizes for the Score.
    It will probably flatten the Error regression doing so, the tonal balance should be more neutral.
  • The EQs are starting point and may require tuning (certainly at LF).
  • The range above 10kHz is usually not EQed unless smooth enough to do so.
  • I am using PEQ (PK) as from my experience the definition is more consistent across different DSP/platform implementations than shelves.
  • With some HP/amp combo the boosts and preamp gain need to be carefully considered to avoid issues
Good L/R match.

I have generated one EQ, the APO config file is attached.

Score no EQ: 73.4
Score Armirm: 92.4
Score with EQ: 94.9


Code:
AKG K240 APO EQ -1.5dB@HF 96000Hz
June152021-095241

Preamp: -9.4 dB

Filter 1: ON PK Fc 29 Hz Gain 9.4 dB Q 0.68
Filter 2: ON PK Fc 216 Hz Gain -2.7 dB Q 0.88
Filter 3: ON PK Fc 1695 Hz Gain 7.2 dB Q 1.96
Filter 4: ON PK Fc 2597 Hz Gain -1.95 dB Q 4.58
Filter 5: ON PK Fc 4704 Hz Gain 8 dB Q 4.35
Filter 6: ON PK Fc 7789 Hz Gain -7 dB Q 4

View attachment 135640
What Target Curve are you using there? I was gonna say you're using your own Target Curve that you created....the one you derived as Amir's preffered target based on you analysing the general trend of Amir's headphone EQ's.....but now I look more closely I think you're using the Harman Curve (just because the y-axis is zoomed out it looks different)?
 

Thalis

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Here are some thoughts about the EQ.

Notes about the EQ design:
  • The average L/R is used to calculate the score.
  • The resolution is 12 points per octave interpolated from the raw data (provided by @amirm)
  • A Genetic Algorithm is used to optimize the EQ.
  • The EQ Score is designed to MAXIMIZE the Score WHILE fitting the Harman target curve with a fixed complexity.
    This will avoid weird results if one only optimizes for the Score.
    It will probably flatten the Error regression doing so, the tonal balance should be more neutral.
  • The EQs are starting point and may require tuning (certainly at LF).
  • The range above 10kHz is usually not EQed unless smooth enough to do so.
  • I am using PEQ (PK) as from my experience the definition is more consistent across different DSP/platform implementations than shelves.
  • With some HP/amp combo the boosts and preamp gain need to be carefully considered to avoid issues
Good L/R match.

I have generated one EQ, the APO config file is attached.

Score no EQ: 73.4
Score Armirm: 92.4
Score with EQ: 94.9


Code:
AKG K240 APO EQ -1.5dB@HF 96000Hz
June152021-095241

Preamp: -9.4 dB

Filter 1: ON PK Fc 29 Hz Gain 9.4 dB Q 0.68
Filter 2: ON PK Fc 216 Hz Gain -2.7 dB Q 0.88
Filter 3: ON PK Fc 1695 Hz Gain 7.2 dB Q 1.96
Filter 4: ON PK Fc 2597 Hz Gain -1.95 dB Q 4.58
Filter 5: ON PK Fc 4704 Hz Gain 8 dB Q 4.35
Filter 6: ON PK Fc 7789 Hz Gain -7 dB Q 4

View attachment 135640


Trying out your EQ on the Mk II. Quite similar to the EQ from AutoEQ (RTINGS) for the Mk II but with a bit more sub bass emphasised. Mids are the same and perhaps the highs are not as hot. Overall not bad at all. Can't hear any distortion with low deep bassy tracks. Been listening to lots of Ozric Tentacles recently.

Amir's EQ just did not remove the mid bass that was a bit emphasised and bleeding into the mids (unless I am doing it wrong). For comparison I have the SHP9500 (Oratory) and the Senn HD280 Pro (Innerfidelity/Oratory). Overall I think your EQ is closer to Oratory's for the SHP9500 (in terms of sound reproduction).

I am sure my sample of the Mk II has the same drivers as the Studios. As for the pads I have "generic" velours that seem to have the same material as the Beyers'. They might make the Mk II a wee bass shy but the overall sound and soundstage are actually quite impressive. Almost as good as the SHP9500 (they do go much deeper though).
 

Thalis

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@Maiky76

After going back and forth using your PEQ and the one from AutoEQ, to my ears yours do end up "collapsing" the spatial qualities somewhat. The top end sounds a bit muffled and the bottom end sounds that bit more muddled compared to the one from AutoEQ. The curve from AutoEQ removes a lot of the mid bass so maybe that's why the bottom end is cleaner?

Now I am wondering if there are differences between the Studios and the Mk II since I do not have the Studios to compare. Also I noticed the pads in Amir's sample looks very oddly attached... like they are not fully snug to the cups.

Here is my Mk II... please disregard the "chopstick" mod I did to it that defeats the spring loaded headband (so it fits my head perfectly without having the headband to self adjust for the extra comfort). It just show that i always try to get pads to fit as snug as possible.

AKG K240 MkII 01.jpg
 

Thalis

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Hello All,

Yesterday I received a pair of these headphones from Amazon. Tomorrow, Friday I will put them on the hammer and give them a test.

Thanks DT


You got the Studios or the Mk II?
 

Blank Verse

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Proper K240s are K240DF, K240M, K240 Sextet.
When 240M were discontinued, noone in studios liked replacement 240M mk2 which are these.
The K240M (Austrian made, 600 ohms) is a great headphone, and although I haven't listened to the new version Amir reviewed here, I don't see how they could sound anything alike, based on his impressions of the new ones.

The absolute best, most neutral and accurate, and with better soundstage, is supposed to be the K240DF, which is a version of the K240M with tuned drivers and housing to match the Diffuse Field curve, and needed to pass some stringent requirements from a German Broadcasting Institute, to make these headphones a suitable replacement for mixing with monitors in a specific configuration in a room with certain qualities.

In my experience the K240M is fairly neutral itself. I don't find the bass lacking at all like some people claim, but I removed the cup enclosure foam backing in mine, and this might have changed their signature slightly (though probably not dramatically, going by other people's comments who listened to them both with and without foam). They are very polite and pleasant headphones, perhaps not overly quick or detailed, and without as much extension in the treble and bass as more modern headphones, but very good headphones nonetheless. The mids are excellent in particular, and even the treble and bass lack any obvious faults except if you nitpick. For example, the treble is without sibilance, though it is not as airy as it could be either, but violin sections, for example, sound realistic. I notice they are not as nimble as others (probably due to the driver technology used).
 
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