AKG K60 Vintage Headphone Review

[amirm]

This is a review, listening tests and detailed measurements of the AKG K60, circa 1970s, new old stock headphone review. It is on kind loan from a member and costs US $170.

I am stunned how fresh, new and clean this headphone is! It feels like you have gone back in time. Owner sent this to me as AKG Vienna was supposed to have built this based on research:

Sounds kind of like how Harman researched headphone preference. Let's see where they got.

AKG K60 Headphone Measurements
They say a picture is worth a 1000 words:

I guess their research told them the main thing we care about is 100 to 500 Hz which considering that is vocal range, maybe that makes sense.

I am ignoring the bass distortion as that is high due to lack of output:

Take caution in looking at absolute distortion levels when the response is not flat:

Group delay is bizarre:

Impedance is quite high:

Sensitivity is slightly better than average:

AKG K60 Listening Tests
Listening to my first track, produced the muffled, "closed in a box" sound that you would expect. Interestingly, it was not annoying. It was a clean midrange response.

Conclusions
We have come a long way as far as knowing what a good headphone could be. Clearly a lot of bad ideas were going around decades back, even with good intentions in research and design.

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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/

 

[heraldo_jones]

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">via GIPHY</a></p>

 

[GXAlan]

E-library page - AES

AES E-Library ← Back to search

aes2.org

It is this headphone

 

[Doodski]

Well... I never in a million years expected this review. LoL.. Totally blindsided and a very interesting review.

 

[GXAlan]

 

[solderdude]

requires a new category above '1' poor in the poll.
One could call it '0' awful.

That said, most headphones of that era probably did not measure well compared to today's standards.

 

[ObjectiveSubjectivist]

Old headphones, what would you expect.

 

[Saponetto]

Mostly interesting, anyway.
Thanks for this review @amirm

 

[DSJR]

Weren't the extremely heavy but popular Koss Pro 4AA 'phones from this period similar in mid to upper balance (maybe there was more low bass in this latter though)?

 

[Vini darko]

No EQ section with recommendation. Who are you and what have you done with Amir?

 

[Maiky76]

Here are some thoughts about the EQ.
Please report your findings, positive or negative!

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 (and other constrains) with a fixed complexity.
  This will avoid weird results if one only optimizes for the Score, start your journey here or there.
  There is a presentation by S. Olive here.
  It will probably flatten the Error regression doing so, the tonal balance should be therefore more neutral.
• The EQs are starting point and may require tuning (certainly at LF and maybe at HF).
• The range around and 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 (loss of Dynamic range) need to be carefully considered to avoid issues with, amongst other things, too low a Max SPL or damaging your device. You have beed warned.
• Not all units of the same product are made equal. The EQ is based on the measurements of a single unit. YMMV with regard to the very unit you are trying this EQ on.
• I sometimes use variations of the Harman curve for some reasons. See rational here and here
• NOTE: the score then calculated is not comparable to the scores derived from the default Harman target curve if not otherwise noted.

Vintage!
Not great L/R match.

I have generated one EQ, the APO config file is attached.
Score no EQ: -5.2
Score with EQ: 85.5

AKG K60 APO EQ Flat@HF 96000Hz
June072024-170645

Preamp: -10.00 dB

Filter 1: ON PK Fc 47.5 Hz Gain 7.46 dB Q 0.79
Filter 2: ON PK Fc 76.7 Hz Gain 11.42 dB Q 1.12
Filter 3: ON PK Fc 111.7 Hz Gain -15.76 dB Q 1.52
Filter 4: ON PK Fc 287.0 Hz Gain -12.13 dB Q 0.76
Filter 5: ON PK Fc 1142.5 Hz Gain 8.36 dB Q 1.34
Filter 6: ON PK Fc 4160.4 Hz Gain 5.73 dB Q 1.22
Filter 7: ON PK Fc 6192.6 Hz Gain -6.69 dB Q 5.00

 

[InfiniteJester]

No EQ section with recommendation. Who are you and what have you done with Amir?

You cannot fix this with EQ and the recommendation status should be fairly obvious.

This is a historic curiosity, nothing else. Only suitable for collectors.

 

[amirm]

Score no EQ: -5.2

Our first headphone with negative score?

 

[Nopiano]

Weren't the extremely heavy but popular Koss Pro 4AA 'phones from this period similar in mid to upper balance (maybe there was more low bass in this latter though)?

Yes, they were awful, weren’t they? Headcrushers, I used to call them! I’d like to see the brilliant original Sennheiser HD414 alongside the AKG as I’m pretty sure I got mine in about 1971.

 

[Joachim Herbert]

maybe there was more low bass in this latter though

No.

 

[Maiky76]

Massdrop 99 Noir:

 

[LIΟN]

As soon as I saw the graph, the phrase came to mind, “What are you listening to?”

 

[Jimbob54]

View attachment 373632
View attachment 373634
View attachment 373633

Interestingly- the blurb on the middle pic sounds exactly the same as the bullshit most hifi makers (and reviewers) still spew out today:

Like being there.....
Superb transient response.....
Accurate bass (huh?)
Transparent....

 

[solderdude]

Yes, they were awful, weren’t they? Headcrushers, I used to call them! I’d like to see the brilliant original Sennheiser HD414 alongside the AKG as I’m pretty sure I got mine in about 1971.

HD414 from the same time period. These were quite comfortable though. (target = horizontal line)

and a Roelofs from the same time period:

and a 2015 (€ 5.-) headphone below

 

[oratory1990]

Considering how there was not much in terms of measurement equipment available during the development of this headphone, they're actually surprisingly close.

(They're not close *at all*, but imagine having to come up with a speaker design for headphones without being able to use an ear simulator during development..)