AKG K371 Review (closed back headphone)

[Frank Dernie]

You can use them powered off, so I expect the electronics are not in use.

Just tried this and with them switched off I get zero sound, so mine certainly don't work when powered off.

 

[rxp]

I get the hype of this but I can't see myself ever buying it. If I want a perfect Harman target without EQ the Galaxy Buds range are way more flexible. Being insert types they also don't have bass frequency response consistency issues - although ear canal length is something that you can tune.

 

[jhaider]

Just tried this and with them switched off I get zero sound, so mine certainly don't work when powered off.

K371BT? I just confirmed - with power off and the headphone cord connected to the Lightning dongle I definitely get sound. It sounds oddly hollow (switch doesn’t change things) but I’ve also never driven them direct from the phone before. Switching on does not change that.

Furthermore, the waterfall priority order seems to be hardwire over BT. Mine are only BT connected to my work laptop and it does not switch input to BT if music is playing over the cable.

 

[Frank Dernie]

K371BT?

No.
All my comments were answering the query about the N90Q, which I own.

 

[brucetwhite]

This is a review and detailed measurements of the AKG K371 closed-back headphone. I purchased this last summer and it currently costs US $149 on Amazon including shipping.

Note: our company, Madrona Digital, carries various Harman brand products although not the AKG products.

The K371 is made out of plastic but has a nice finish which belies its cheap structure:

View attachment 107868

I especially like the feel of the pads. They are not huge but big enough to fit around my ears. Inside height of the pad is 2.51 inches. Inside width is 1.62 inches. With no depression, the pad depth to the driver is 0.8 inches. Outside diameter of the pad is 4 inches by 3 inches.

Three different cords are supplied which terminate into a 3-pin mini-XLR:

View attachment 107869

Let me warn you about something I hate about these headphones: the headband adjustment mechanism. It either gets stuck and doesn't move at all. Or all of a sudden moves a bunch of notches. I also see reports of the mechanism failing which means you have to send them back to Harman/AKG for repair (you pay shipping even under warranty).

Clamp pressure is a bit much especially if you wear glasses at first but gets better with some use. When I take them off, the pads are quite warm so likely in summer, they will not be comfortable if your room is not cool.

Note 1: The measurements you are about to see are preformed using standardized GRAS 45CA headphone measurement fixture. Headphone measurements require more interpretation than speaker tests and have more of a requirement for subjective testing as a result. In addition, comparison of measurements between different people doing it using different configurations requires fair bit of skill. So don't look for matching results. Focus on high level picture.

Getting the K371 seated did not require much work and indeed, measurements track some of the others I have seen using same fixture as I use.

AKG K371 Measurements
As usual we start with frequency response of K371. They are said to follow the Harman target. Let's see if that is the case:

View attachment 107870

This looks to be closest we have gotten to the target. Indeed in sub-bass where vast majority of headphones fall off, the K371 actually overachieves a bit. Then again the Harman fixture is a bit different than what the rest of us use so maybe in their fixture that was right on the money. Either way, during equalization and listening tests we will investigate this further.

Following down the curve, we have a dip around 3.8 to 3.9 kHz. It is a shame as past that the response envelop more or less follows our target.

We can subtract the response from the target and see the deviations:

View attachment 107871

Distortion is better than average:

View attachment 107872

The 94 dB line in blue shows extremely good performance. That keeps up even at 104 dBSPL.

Group delay gives us some clues to things going wrong with manifested in frequency response graph:
View attachment 107873

We get similar clues in impedance versus frequency:
View attachment 107874

This is a very sensitive headphone so don't need much horsepower to drive it:

View attachment 107875

AKG K371 Headphone Listening Tests & EQ
First impression was a very good response albeit, with a tad too much bass and a bit of exaggerated highs and harshness. You really had to listen to find these though. I also found the vocals to be a tiny bit recessed. Overall, you could listen to these headphones and be perfectly fine without any equalization.

But we, at least I, want perfection so let's apply a bit of touch up as instructed by the frequency response:
View attachment 107876

I first boosted the lower treble and while that opened the sound up and nicely increased detail, the sound became somewhat bright. So I went after one of the peaks at 6800 and pulled that down. That fixed most of that. I initially had the bass pulled down some as you see in Band 1 crossed out above. I turned that off as it nicely countered the slightly sharpness that was left. Once there, this headphone was absolutely delightful to listen to. I could only find the slightest amount of harshness left (which could be magnification of what is in the music).

It was such a pleasure to listen to music with deep bass with and without EQ and hear those notes resonate in my ear even at very modest playback levels. Tracks like
Nachtschwärmen, by Regen:Tropfen were stunning in their impulsive bass notes:

And so was the rest of the spectrum. Notes come from every end of spectrum at no time do you say, "oh, why is that too high or too low." It is all balanced to near perfection.

Spatially without EQ the experience is fine. My boost of the lower treble however helps a lot here to get very good "soundstage" and layering of instruments. Mind you, it is not crazy nice like that if Sennheiser HD800s and such but it is "correct" and satisfying.

Conclusions
Some of you have been asking, even demanding to see a headphone that does the job without EQ. Well, the AKG K371 is it. My equalizations of it are subtle (but worthwhile) so you could indeed live without it. I do however highly recommend that you deploy EQ if you can.

You could say I am rubber stamping the Harman research and approach to headphone tonality. But such was not the case. I went into this review critically and thinking hard about what rating to give the headphone. I almost notched it down one step to avoid accusation of bias. But at the end, the truth is the truth. Years of research by Harman has resulted in creating headphone tonality that matches what I dream about getting out of best speakers in the world. To the extent their research goes after that sound (tonality of a good speaker in the room), it is natural that Harman and I land in the same spot.

Note that my strong positive recommendation for AKG K371 is for sound only. Physically, this headphone may not do it for you. It may get too hot around your ears, and the adjustment mechanism may annoy you or break. I leave that to you to decide.

------------
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/

Thanks so much for your comprehensive reviews. I just started reading this site and am mightily impressed. A question about equalization of headphones. How do you do the equalization, and what kind of gear is required? I'm guessing that this is a PC app so you deal with digital sound files, is that correct?

I would like something that would do that without the PC, maybe a chain that goes like this:

vinyl -- phono preamp -- programmable parametric equalizer -- headphone amp

Do you know of gear like this?


Thanks for tolerating a newbies questions.

Bruce

 

[solderdude]

Consider something like the DEQ2496

vinyl -- phono preamp -- programmable parametric equalizer -- headphone amp

becomes:
vinyl -- phono preamp -- DEQ2496 -- headphone amp

The DEQ2496 surpasses vinyl in specifications.

 

[infinitesymphony]

I would like something that would do that without the PC, maybe a chain that goes like this:

vinyl -- phono preamp -- programmable parametric equalizer -- headphone amp

Consider something like the DEQ2496

Or the miniDSP 2x4HD ($205), though that does require a computer to initially program the parametric EQ (PEQ).

Or this 10-band rack PEQ:

 

[Robbo99999]

Thanks so much for your comprehensive reviews. I just started reading this site and am mightily impressed. A question about equalization of headphones. How do you do the equalization, and what kind of gear is required? I'm guessing that this is a PC app so you deal with digital sound files, is that correct?

I would like something that would do that without the PC, maybe a chain that goes like this:

vinyl -- phono preamp -- programmable parametric equalizer -- headphone amp

Do you know of gear like this?


Thanks for tolerating a newbies questions.

Bruce

I use miniDSP 2x4, costs $95, (cheaper than the HD version that @infinitesymphony linked in the post above) for sound processing from my TV, it just sits inbetween my TV and my active speakers, connected via RCA cables. It's programmable via PC interface to program in your parametric filters (EQ). Here's the miniDSP, it's about the cheapest standalone equalisation solution, and given you'll be processing vinyl you don't need to worry about a high SNR, so this miniDSP 2x4 is probably right on in terms of not going over the top on SNR quality: https://www.minidsp.com/products/minidsp-in-a-box/minidsp-2x4
I think they advertise that at about 90dB SNR, but it's probably a little less than that if Amir were to measure it, I bet. I use it for sound processing of TV & movies in a 2 channel system. You can add a sub to that miniDSP too.

 

[Grotti]

Thanks so much for your comprehensive reviews. I just started reading this site and am mightily impressed. A question about equalization of headphones. How do you do the equalization, and what kind of gear is required? I'm guessing that this is a PC app so you deal with digital sound files, is that correct?

I would like something that would do that without the PC, maybe a chain that goes like this:

vinyl -- phono preamp -- programmable parametric equalizer -- headphone amp

Do you know of gear like this?


Thanks for tolerating a newbies questions.

Bruce

Not as cheap as the other suggestions, but it has to be mentioned as well: RME ADI-2 pro fs R BE. Just take a look arround: you will find it in many threads.

 

[Pdxwayne]

Hmm, I do have Minidsp 2x4 HD sat unused.....Maybe I can do this to add eq:

Laptop -> KTB -> minidsp -> headphones amp

 

[Robbo99999]

Hmm, I do have Minidsp 2x4 HD sat unused.....Maybe I can do this to add eq:

Laptop -> KTB -> minidsp -> headphones amp

If you've got a laptop just use a software solution for equalisation, eg EqualiserAPO is totally flexible/accurate/legit and is completely free, no reason to use hardware like miniDSP for EQ when you've got the power of a laptop at your fingertips in your audio chain. EqualiserAPO is a lot more powerful than miniDSP in some of it's flexibility and number of filters allowed.

 

[Jimbob54]

If you've got a laptop just use a software solution for equalisation, eg EqualiserAPO is totally flexible/accurate/legit and is completely free, no reason to use hardware like miniDSP for EQ when you've got the power of a laptop at your fingertips in your audio chain.

Beat me to it!

 

[Pdxwayne]

If you've got a laptop just use a software solution for equalisation, eg EqualiserAPO is totally flexible/accurate/legit and is completely free, no reason to use hardware like miniDSP for EQ when you've got the power of a laptop at your fingertips in your audio chain. EqualiserAPO is a lot more powerful than miniDSP in some of it's flexibility and number of filters allowed.

Thanks for the suggestion. I did some search about it and I still don't feel safe using it. Sorry, too paranoid about safety.

 

[weasels]

Beat me to it!

yup - i have an old (10+ year) laptop that I use expressly for this purpose.

 

[Feelas]

Thanks for the suggestion. I did some search about it and I still don't feel safe using it. Sorry, too paranoid about safety.

What are you worried about, exactly?

 

[Transmaniacon]

I picked up a pair of these last year, the sound is fantastic and I find them comfortable and easy to wear for long periods.

 

[Pdxwayne]

What are you worried about, exactly?

Issues mentioned during online search were associated trojan like app could be installed, app hard to uninstall, doesn't work, etc.

I will go with something I know first before venture out.....

 

[Feelas]

Issues mentioned during online search were associated trojan like app could be installed, app hard to uninstall, doesn't work, etc.

I will go with something I know first before venture out.....

Sometimes better safe then sorry, if you're gonna be bothered about it. Especially since you've got the gear already

 

[Robbo99999]

Issues mentioned during online search were associated trojan like app could be installed, app hard to uninstall, doesn't work, etc.

I will go with something I know first before venture out.....

EqualiserAPO, I haven't heard of any security issues with it. Also nothing picked up by my different malware scanners. I don't think this concern has much basis in reality. It's also quite easy to use, and if it's too difficult to use then you can use it with the PEACE extension that turns it into a supposedly more user friendly screen, but EqualiserAPO itself is useable & powerful if you spend a bit of time with it.

 

[sweetchaos]

doesn't work, etc.

If people say 'Equalizer APO' doesnt work, then they have it misconfigured.

You can follow my guide on how to use 'Equalizer APO' or 'Peace' here.