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Drop AKG K7XX Review (Headphone)

amirm

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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:

Drop AKG K7XX Review open back Headphone.jpg


The giant cups are comfortable and the headphone itself is light for its size at 300 grams:

lightest headphone open back reviewed.png


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:

Drop AKG K7XX Measurements Headphone.png


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:

Drop AKG K7XX Relative Frequency Response Measurements Headphone.png


The big news is in distortion:

Drop AKG K7XX Distortion vs Frequency Response Measurements Headphone.png


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.

Drop AKG K7XX THD Distortion vs Frequency Response Measurements Headphone.png


Group delay is fuzzy across the full spectrum which I had not seen before:

Drop AKG K7XX Group Delay Measurements Headphone.png


Impedance is pretty constant and on the low side:

Drop AKG K7XX impedance Measurements Headphone.png


Sensitivity is slightly worse than average:

Most efficient headphone reviewed.png


Drop AKG K7XX Red Edition Listening Tests and Equalization
Instant impression was dull tonality so out came the EQ tools and quick:

Drop AKG K7XX Equalization EQ Headphone.png


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.

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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/
 

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NoteMakoti

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I wish the HD600/650 fanboys from a decade+ ago were alive to see this.

I still want to hunt down an old K701, just for nostalgia's sake. I always loved how they looked.
 

solderdude

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Note: a horizontal line is 'audible flat' acc. to me. The dip around 4kHz isn't as deep in reality and the resonances above 10kHz will be smaller in reality due to a pinna-less measurement.

K702 fitted with K7XX pads vs K7XX

k7xx-pu-vs-k702-with-k7xx-pads.png


K702 is slightly more damped.

For completeness K712 vs K7XX
k712-bn-vs-k7xx-gn.png


my conclusion:

The K7XX has a a good bass response that doesn’t sound rolled-off like many other K7** models. (excluding the K712 I reckon). Not suited for bass-heads.
Treble and upper mids are much better in balance than most other K7** models.
The sound is warm and full with tight and not emphasized nor colored bass.
Mids are a tad on the ‘laid back’ side of things but not as much as the K712.
Treble quality is not on par with that of the bass and mids, the K712 is slightly better in this department and sounds a bit ‘smoother’.
The K7XX is a bit coarse/grainy as in not ‘smooth, silky’ like TOTL headphones often show.
Those that find the HD58X, HD650 etc. too ‘forward’ may find the K7XX a nicer sounding option… but with less refined treble.
The treble amount is good though so no harsh or shrill mids anywhere.
Not suited to be driven directly from phones, tablets. It may not play impressively/loud enough.
Higher end DAPs (with a higher output voltage) and desktop gear is what’s required for this headphone.
 
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Presently42

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I had the K701 for years, before I gave them to a friend after I'd bought the HD800. I loved everything about them: the looks, the comfort, the sound. Everything sounded right on them. When I got the HD800, supposedly a K701 with more bass, everything sounded wrong. Having listened to music on the K701 for so long, that sound was correct, and all else was wrong. The HD800's sound made me depressed, and I nearly asked my friend for the K701 back - and nearly bought the Clear! Then I discovered eq, played around with it and eventually settled on the HD800 eq'd to the Harman curve. My life has been better ever since - a rather extreme statement; but it nicely encapsulates just how important music is to me.

The K701 were measured by @Sean Olive when he was doing his research - perhaps he'd be willing to share the data if we ask nicely.

P. S.: That's the first time I see headless panther's head - he's a beefeater! Perhaps he's had too much to drink, and rather lost his head....
 

respice finem

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The headphone test curse stikes again (the pricier, the worse)... IDK the price, but any "limited edition" is not meant to be cheap.
 

sweetchaos

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To import this PEQ profile into 'Equalizer APO', use:
Preamp: -5.7 dB
Filter 1: ON LS Fc 55 Hz Gain 5.3 dB Q 1.0
Filter 2: ON PK Fc 230 Hz Gain -1.5 dB Q 1.0
Filter 3: ON PK Fc 1000 Hz Gain 4.0 dB Q 1.0
Filter 4: ON PK Fc 1700 Hz Gain -4.0 dB Q 3.0
Filter 5: ON PK Fc 3100 Hz Gain 4.0 dB Q 3.0
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:
See my GEQ guide for 10-band, 31-band, and 127-band GEQ profiles.
 
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solderdude

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The headphone test curse stikes again (the pricier, the worse)... IDK the price, but any "limited edition" is not meant to be cheap.

The K7XX is actually a cheaper model ($ 200) compared to the K712.
About the same price as a K702 + loose K712 pads.
 

Robbo99999

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@amirm , thanks for testing this one, it's one of the headphones I've been more interested in. Regarding distortion between 1-2kHz, I have the K702 which is similar to the K7XX in outward design (I'm not sure if internals like drivers are different), and one of my K702 (from yr 2015) has quite high distortion between 1-2kHz similar to this K7XX you measured, whereas my other sample (from yr 2020) doesn't have that distortion...... here's the graphs of my two K702's (from Oratory), the highest red line is around 102-105dB at 1kHz depending on headphone:

K702 from 2015:
K702 Oratory Distortion.png


K702 from 2020:
#2 K702 distortion.png


I currently have both of those two K702's (that have been measured by Oratory) EQ'd to their own individual measurements to the Harman Curve, and I do actually prefer the newer model (which happens to have less distortion between 1-2kHz. That could be down to the pads though, they're thicker on my older K702, as I bought supposedly genuine pads from Thomann, but they are visibly thicker than the stock pads on my new K702 - not by a massive amount, but definitely different, so perhaps that is more a factor of my preference rather than the distortion differences between the two headphones. My newer K702 is clearer in the bass and just throughout the frequency range up to the vocals - I'm unsure if this is due to the slight differences in pads (although both measured with said pads) or whether it's distortion related. Having said that, even my old K702 with the higher distortion between 1-2kHz is a more preferred headphone for me than my other headphone models you see in my sig, which have lower measured distortion......so I'm not totally sold on distortion being the most significant factor. I primarily like my K702 for their clarity/detail combined with good soundstage (best of my headphones).

Amir, I notice that the K7XX doesn't have angled pads whilst the K702 does have angled pads, so perhaps you'd find the K702 has better soundstage than the K7XX.

Ah, one note about the EQ - if you had aligned the measurement on the target at 1kHz then you wouldn't have to EQ up the distortion problem area as much and also the treble above 10kHz would be better aligned to the curve too, also would require massively less Low Shelf Bass boost, and instead you'd be putting a wide peak filter to remove the excess between about 80-800Hz. Would have been an overall easier EQ and better alignment with energy above 10kHz - I know EQ'ing is relative so I'm a bit on the fence re whether it would mean less stress on the delicate 1-2kHz area, but generally I think it would have been a more efficient choice.
 

Presently42

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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.

@amirm, according to this site and sorta drop themselves, these cost 200 USD
 
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amirm

amirm

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Ah, one note about the EQ - if you had aligned the measurement on the target at 1kHz then you wouldn't have to EQ up the distortion problem area as much and also the treble above 10kHz would be better aligned to the curve too,
As I have explained a number of times, this is a zero sum game. To get alignment at 1 kHz, I would have had to turn up the gain on the amp which would in turn increase distortion in that region -- just like EQ does. Alignment is a visual thing for humans on that graph. It has no other meaning.
 

Jimbob54

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Another crash and burn....

Of the teutonic triumvirate (senn hd6zz, beyer 770/880/990 and akg k7zz) only the Senns look to be holding their head above water under scrutiny.
 

Robbo99999

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As I have explained a number of times, this is a zero sum game. To get alignment at 1 kHz, I would have had to turn up the gain on the amp which would in turn increase distortion in that region -- just like EQ does. Alignment is a visual thing for humans on that graph. It has no other meaning.
Although you would have been able to get away with either a very small Low Shelf Bass Boost or in fact no bass boost (allowing the headphone to roll off naturally) if you would have aligned at 1kHz, and I've found with my K702 that the headphone responds better to not having a Low Shelf Boost remain below 30Hz......and as a bonus you would have had better alignment in the 10kHz+ area......so overall in my experience of EQ'ing a headphone that's very similar to your K7XX, you would have had an improved listening experience.

EDIT: it's a shame you didn't bother to comment on my other points/parallels I made re distortion differences between my two K702's and the K7XX you measured, along with other points I made......instead you pick one element of my post & focus on the negative & the attack....praps beneficial to take some deep breaths and gain some general perspective when responding to member's posts. I'm trying to provide some interesting information/parallels and yet you focus on the critique.
 
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restorer-john

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@amirm Thanks for reviewing these.

I have 2 pairs of AKG-702s here, one about 6 years old and one pair about 1 year old. Also a pair of AKG-601 and some old AKG-500s.

The impedance curves on all of them pretty much match the shape of your plot just with higher nominal for the 500 and 601s. Incidentally, my old AKG-500s and the AKG-601s had virtually identical impedance plots to one another.

Considering how much I like the headphones and am very sensitive to distortion in the midband, I'm saved by the fact I just don't play headphones very loud at all.
 

xaviescacs

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Thanks @amirm ! So many great reviews in so little time, wow! What's going on? That's awesome.

Very disappointed with these headphones. I love my K701 bought 16 years ago and I thought those would be similar.

I also love mines, bought 12 years ago, but now I'm little puzzled because I'm not sure if what I love is the distortion. I assume I should learn to hear distortion.

With the excitement of seeing my (almost) headphones reviewed I forgot to thanks @amirm for this review.
 

restorer-john

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I assume I should learn to hear distortion.

I'm going to investigate my pairs here for sure. I am seriously interested to see if all my AKGs have >0.5% THD right in the midband at levels in the mid 90s.
 
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