This is a review and detailed measurements of the Drop AKG K7XX Limited Edition Red, open back headphone. It is on kind loan from a member. I can't find the price on it. If someone knows, please post and I will udpate the review.
I must say, I like the look of this headphone. It is both serious and playful:
The giant cups are comfortable and the headphone itself is light for its size at 300 grams:
Inside cup dimensions are 66 by 23 mm (diameter x depth).
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 confirm 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!
The large cups made an easy job of mounting them on my fixture and getting good measurements on first try.
Drop AKG K7XX ohm Measurements
Let's start with our usual frequency response measurements:
As we see the only area that more or less hits our target is 100 to 500 Hz and then again above 8 kHz. Everywhere else there is a shortfall. We can see the differential better for the purposes of equalization:
The big news is in distortion:
Ouch, ouch, OUCH! If you are going to have distortion, please don't have it where our hearing is most sensitive in the 2 to 5 kHz. Unfortunately that is the area of frequency response we need to boost as well. Let's pray "measurements don't tell the story" here or we are toast.
Group delay is fuzzy across the full spectrum which I had not seen before:
Impedance is pretty constant and on the low side:
Sensitivity is slightly worse than average:
Drop AKG K7XX Red Edition Listening Tests and Equalization
Instant impression was dull tonality so out came the EQ tools and quick:
Bass boost worked very well. As did the the other two boosts until I listened a bit more to my reference vocal tracks. At times, I started to clearly here a secondary distorted version of the female vocals. Turning off the filter in pink reduced most of it. I originally had it at 1.3 kHz and at higher amplitude. With that setting the headphone sounded great at times, and horrible because of distortion other times. I adjusted the levels of that filter down and shifted it to 1 kHz. Added that other notch. It reduced the magnitude of the distortion some but still very problematic. Once you heard it, you also couldn't "unhear" it.
Shame the distortion is so bad as spatial qualities were pretty good (B+).
Conclusions
The tonality of the AKG K7XX is wrong out of the box. This is the case for many headphones but what was rather unique here was severe distortion in the 1 to 2 kHz. This stops you from correcting the response in that all important region. Even without correction, the sound is not quite right as distortion is high even before you boost it. This is a clear defect in design which should have been caught and fixed. Maybe there was too much cost pressure from Drop and they reached for the cheapest drivers they had; I don't know. What I do know is that they screwed up a headphone that otherwise could have performed very well with equalization. And be comfortable to boot.
I can't recommend the Drop AKG K7XX with or without equalization.
-----------
As always, questions, comments, recommendations, etc. are welcome.
Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
I must say, I like the look of this headphone. It is both serious and playful:
The giant cups are comfortable and the headphone itself is light for its size at 300 grams:
Inside cup dimensions are 66 by 23 mm (diameter x depth).
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 confirm 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!
The large cups made an easy job of mounting them on my fixture and getting good measurements on first try.
Drop AKG K7XX ohm Measurements
Let's start with our usual frequency response measurements:
As we see the only area that more or less hits our target is 100 to 500 Hz and then again above 8 kHz. Everywhere else there is a shortfall. We can see the differential better for the purposes of equalization:
The big news is in distortion:
Ouch, ouch, OUCH! If you are going to have distortion, please don't have it where our hearing is most sensitive in the 2 to 5 kHz. Unfortunately that is the area of frequency response we need to boost as well. Let's pray "measurements don't tell the story" here or we are toast.
Group delay is fuzzy across the full spectrum which I had not seen before:
Impedance is pretty constant and on the low side:
Sensitivity is slightly worse than average:
Drop AKG K7XX Red Edition Listening Tests and Equalization
Instant impression was dull tonality so out came the EQ tools and quick:
Bass boost worked very well. As did the the other two boosts until I listened a bit more to my reference vocal tracks. At times, I started to clearly here a secondary distorted version of the female vocals. Turning off the filter in pink reduced most of it. I originally had it at 1.3 kHz and at higher amplitude. With that setting the headphone sounded great at times, and horrible because of distortion other times. I adjusted the levels of that filter down and shifted it to 1 kHz. Added that other notch. It reduced the magnitude of the distortion some but still very problematic. Once you heard it, you also couldn't "unhear" it.
Shame the distortion is so bad as spatial qualities were pretty good (B+).
Conclusions
The tonality of the AKG K7XX is wrong out of the box. This is the case for many headphones but what was rather unique here was severe distortion in the 1 to 2 kHz. This stops you from correcting the response in that all important region. Even without correction, the sound is not quite right as distortion is high even before you boost it. This is a clear defect in design which should have been caught and fixed. Maybe there was too much cost pressure from Drop and they reached for the cheapest drivers they had; I don't know. What I do know is that they screwed up a headphone that otherwise could have performed very well with equalization. And be comfortable to boot.
I can't recommend the Drop AKG K7XX with or without equalization.
-----------
As always, questions, comments, recommendations, etc. are welcome.
Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
