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AKG K240 55 Ohm Review (Headphone)

amirm

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#1
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:

AKG K240 Review Budget Studio Headphone.jpg


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:

lightest over the ear headphone review.png


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:

AKG K240 Frequency Response Measurements Headphone.png


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:

AKG K240 relative Frequency Response Measurements Headphone.png


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

AKG K240 Distortion Percentage Measurements Headphone.png


AKG K240 Distortion Measurements Headphone.png


Group delay indicates some interference pattern but that is common:
AKG K240 Group Delay Measurements Headphone.png


Sensitivity is a bit below average:

most efficient studio headphone review.png



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

AKG K240 Impedance Measurements Headphone.png


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:

AKG K240 Distortion Equalization EQ Headphone.png


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/
 

Attachments

sweetchaos

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#2
To import this PEQ profile into 'Equalizer APO', use:
Preamp: -11.7 dB
Filter 1: ON LS Fc 40 Hz Gain 7.0 dB Q 1.0
Filter 2: ON LS Fc 75 Hz Gain 4.0 dB Q 1.0
Filter 3: ON PK Fc 1700 Hz Gain 8.0 dB Q 2.0
Filter 4: ON PK Fc 4700 Hz Gain 8.0 dB Q 4.0
Filter 5: ON PK Fc 8100 Hz Gain -4.0 dB Q 4.0
To import into your favorite PEQ app, enter it manually.
Otherwise, see my PEQ guide.
..................................................................................................................
For those who don't have PEQ-capable app, and want to use GEQs instead.
Preamp: -7.8db
32 7.3
64 1.1
125 -1.3
250 -1.2
500 -1.7
1000 -0.0
2000 3.9
4000 2.1
8000 -4.0
16000 -2.2
Preamp: -6.8db
20 4.5
25 5.1
32 4.8
40 4.0
50 2.6
63 1.6
80 0.4
100 -0.3
125 -0.9
160 -1.0
200 -1.0
250 -1.1
315 -1.2
400 -1.1
500 -1.1
630 -1.0
800 -0.9
1000 -0.5
1250 0.6
1600 5.9
2000 3.5
2500 -0.1
3150 -0.8
4000 1.6
5000 4.9
6300 -1.4
8000 -5.5
10000 -2.2
12500 -2.1
16000 -2.7
20000 -0.4
If you want to import into "Wavelet" (Android App):
GraphicEQ: 20 -0.2; 21 -0.2; 22 -0.2; 23 -0.2; 24 -0.2; 26 -0.2; 27 -0.2; 29 -0.2; 30 -0.2; 32 -0.2; 34 -0.2; 36 -0.2; 38 -0.4; 40 -0.8; 43 -1.3; 45 -1.6; 48 -2.1; 50 -2.4; 53 -2.8; 56 -3.2; 59 -3.6; 63 -4.0; 66 -4.4; 70 -4.7; 74 -5.1; 78 -5.4; 83 -5.7; 87 -5.9; 92 -6.2; 97 -6.4; 103 -6.6; 109 -6.8; 115 -6.9; 121 -7.1; 128 -7.2; 136 -7.3; 143 -7.4; 151 -7.4; 160 -7.5; 169 -7.6; 178 -7.6; 188 -7.6; 199 -7.7; 210 -7.7; 222 -7.7; 235 -7.7; 248 -7.7; 262 -7.7; 277 -7.8; 292 -7.8; 309 -7.8; 326 -7.8; 345 -7.7; 364 -7.7; 385 -7.7; 406 -7.7; 429 -7.7; 453 -7.7; 479 -7.7; 506 -7.6; 534 -7.6; 565 -7.6; 596 -7.5; 630 -7.5; 665 -7.4; 703 -7.4; 743 -7.3; 784 -7.2; 829 -7.1; 875 -6.9; 924 -6.8; 977 -6.5; 1032 -6.3; 1090 -6.0; 1151 -5.5; 1216 -5.0; 1284 -4.4; 1357 -3.6; 1433 -2.6; 1514 -1.4; 1599 -0.5; 1689 -0.2; 1784 -0.3; 1885 -1.0; 1991 -2.1; 2103 -3.1; 2221 -4.0; 2347 -4.7; 2479 -5.2; 2618 -5.6; 2766 -5.8; 2921 -6.0; 3086 -6.1; 3260 -6.1; 3443 -6.0; 3637 -5.7; 3842 -5.2; 4058 -4.2; 4287 -2.8; 4528 -1.3; 4783 -1.2; 5052 -2.6; 5337 -4.1; 5637 -5.4; 5955 -6.4; 6290 -7.2; 6644 -7.9; 7018 -8.7; 7414 -9.8; 7831 -11.0; 8272 -11.3; 8738 -10.4; 9230 -9.4; 9749 -8.8; 10298 -8.5; 10878 -8.3; 11490 -8.1; 12137 -8.1; 12821 -8.0; 13543 -8.0; 14305 -8.0; 15110 -7.9; 15961 -7.9; 16860 -7.9; 17809 -7.9; 18812 -7.5; 19871 -6.2
Otherwise, see my GEQ guide.
 
Last edited:

solderdude

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#3
Something that may be important to take into consideration for studio monitoring (not mixing) headphones in general.
Having flat or Harman FR is not paramount, they may well be colored in a certain way, roll-off in the extremes and have an emphasis or dip in certain parts of the FR.

The K240 are not meant to be used as a headphone to enjoy music but rather in a studio to monitor recordings.
In such case it is not about accuracy at all but hearing instruments and voices usually at higher SPL than average and comfort, easy to change pads and occasionally sitting on one or have it drop or janked of your head. You don't want high amounts of lows muddying up the sound nor excessive 2-4kHz range (shout).
Tonal accuracy in the final mix is done afterwards with EQ/effects to get the desired sound. It is not determined by the musician based on what he hears.

It is a studio monitor and sold as such. Some folks assume because they are used in studios (just like many Beyers) they can thus be used for enjoying music as well. A very common 'mistake'. It's akin to folks claiming the DT48 is such a great headphone because it was used for testing hearing.

The elastic bands regulating the headband height loose tension pretty quickly. A horrible construction that AKG should have changed by now.
There are many different K240 iterations by the way. As well as DT770/DT880/DT990's. These are cheap 'throw away' consumables to studios.

Thanks for measuring them. I haven't had the pleasure yet and won't buy them because I am sure I won't be using them to enjoy music.
 
Last edited:

markanini

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#5
. I haven't had the pleasure yet and won't buy them because I am sure I won't be using them to enjoy music.
No big loss, this set is all lower mids, and not in the endearing way some classic open backs emphasize the range. I've tried to consider if it's peculiar tuning has any specific utility for it's intended purpose. I suspect the sound simply was a secondary aspect of it's design, because you can find headphones that are crankable without sounding outright dull and boring like these do.
 

Jimbob54

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#6
Yoiks! Let's hope their hifi offerings fare better. I know of at least one member who would be very keen to see the k702 reviewed. The k371 shows they certainly can make decent sounding cans.
 

Blumlein 88

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K240s once were not from China. They cost lots more. My description of the sound would be about 180 degrees off from Amirs. I've not listened to the current versions. Would be interesting if someone could send you some of the older ones.
 
Last edited:

dmac6419

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#9
K240s once were not from China. They cost lots more. My description of the sound would be about 180 degrees off from yours. I've not listened to the current versions. Would be interesting if someone could send you some of the older ones.
Whats wrong with stuff made in China, the k car wasn't made in China.
 

restorer-john

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#10
Whats wrong with stuff made in China, the k car wasn't made in China either.
AKG headphones took a significant dive in quality. I own/ed several pairs of both Austrian and Chinese AKGs.
 

Blumlein 88

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#11
Whats wrong with stuff made in China, the k car wasn't made in China.
What's wrong is in this particular instance the move from Europe to China apprently wasn't good for the product. Could the people in China have made phones equal to the Austrian models? My guess is they could, but that it wouldn't be as cheap. I'd actually hold AKG accountable for trying to pull a fast one. Keep the product name and basic appearance the same, but make an inferior product for less money. Of course we really need a test of the Austrian version to confirm they aren't more similar than different.
 

YSC

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#12
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/
With headphone dependency on pads and seal for bass or pad bounce, I kind of wonders if the dip is the bounce recreated by the new pads and the bass say can be degraded by the more bass absorbing valour?
 

Anmol

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#13
AKG headphones took a significant dive in quality. I own/ed several pairs of both Austrian and Chinese AKGs.
Any widely available data you can share with us beyond your personal view on quality of akg professional headphones made in China vs Austria?
I have owned 7xx both made in china and old Austrian made 701 , can't tell the difference. While this a single set of cans, akg professional headphones made in China appear ok. How they sound is related to a number of things and made in china is a small part of it.
 

restorer-john

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#14
Any widely available data you can share with us beyond your personal view on quality of akg professional headphones made in China vs Austria?
I have owned 7xx both made in china and old Austrian made 701 , can't tell the difference. While this a single set of cans, akg professional headphones made in China appear ok. How they sound is related to a number of things and made in china is a small part of it.
I'm just a consumer of AKG gear like yourself. However, I've had AKGs forever, several models and everything from the plastic, the leather stitching, embossing and shaping, the cables, the plugs, the fit and finish, and the sound of the 5xx, 6xx and 7xx was worse on the second gen Chinese models. I gave up after Chinese 702s as the Austrian 701s and 702s were/are clearly better.

It was clear to me, Harman just didn't care anymore about what AKG stood for. And then they sold to Samsung. Poor AKG was dragged along in the wake.
 

Helicopter

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#17
Thanks Amir. Perhaps this will work for a cash strapped studio to hear certain details. Obviously a poor choice for enjoying music. I am a little surprised performance is so poor coming from the Harman group.
 
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#18
@Amir - Thanks for the review! I really appreciate you measuring headphones now.

Having said that:

Frequency response measurements with third-party earpads, especially ones like these which are from a different material and have a different "geometry" (they are deeper than the originals) are of limited value. Both from personal experience and from the measurements out there the difference can be huge.
 

Robbo99999

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#19
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/
I'm a bit dubious about the validity of measuring a headphone for a review when it doesn't have the stock pads fitted, as this would certainly influence frequency response as a minimum....I'm not sure if it could have any other positive or negative effects on distortion, and if the original pads were angled (don't know if they are) then any non-stock pads used that are not angled could potentially damage the soundstage aspect too. I'd imagine stock or non-stock pads wouldn't influence the negative aspect you noticed when you say "During playback I could feel the entire cup resonating with each note.", then I think that's a bit of a red flag for this headphone regardless. Given the non-stock pads perhaps we can't place much faith in the measured frequency response though, in terms of it representing a stock K240. Having said this though, the frequency response is quite similar to the frequency response that Oratory published for this headphone, so it looks like in this particular instance that non-stock pads are not that far off from the stock pads in this particular case - so I think we got lucky with this one so-to-speak.

Bass distortion on this headphone is crazy, even at 94dB, so best avoid this headphone.
 

Robbo99999

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#20
I'm just a consumer of AKG gear like yourself. However, I've had AKGs forever, several models and everything from the plastic, the leather stitching, embossing and shaping, the cables, the plugs, the fit and finish, and the sound of the 5xx, 6xx and 7xx was worse on the second gen Chinese models. I gave up after Chinese 702s as the Austrian 701s and 702s were/are clearly better.

It was clear to me, Harman just didn't care anymore about what AKG stood for. And then they sold to Samsung. Poor AKG was dragged along in the wake.
I'm not sold on their being a difference in sound quality between Austrian vs Chinese made AKG's for the same model. I've never seen any measurements backing up the differences, and my understanding is that they are the same. I'm not sold on your conclusion.

EDIT: it's possible stuff like solder quality could be different, as my K702 had the solder fail on it, so I soldered the wires back on myself & it's not failed in the years since.....but as to there being sound quality differences between Chinese & Austrian AKG I'm not sold on.
 
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