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AKG K240 55 Ohm Review (Headphone)

600_OHM

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What are the differences between the current K240 versus the old Sextett/gold ring vintage K240?
Simply put, if audio quality is concerned, which one performs better?
The original K240 Sextet with 6 passive radiators was designed when the engineers notice a big problem way back then - sources DID have some bass, but most cans were unable to reproduce it or very weakly. What happened more often than not, was that in final mixes, the bass was over emphasized.

From a manufacturing standpoint of time and resources, this was a bit costly and perhaps excessive. The simpler solution was instead of striving for bass fidelity, the mid-bass was hyped (since in the 60/70's, there wasn't much EDM dance music. :) This gave it a bass "punch" instead of true fidelity. Which at the time for most pop/rock was acceptable to many.
 

600_OHM

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Group delay between L and R is quite normal. Frequencies below 14Hz are not present in recordings anyway and the wavelength is incredibly long there anyway.

No group delay issues... only FR.
I'll trust you on that. But they did *something* to protect against things like gunshots in the studio. Which makes these cans the absolute WORST thing to watch an action-movie with! Yawn.

And why many drummers really dislike these - those initial strikes are gone. Watch a well-timed video of a drum-solo, and you'll just about see the effect reducing the impact.

I think that's the missing groove of the K240 as a studio "tool", not a hifi can. - everything was designed like you were listening to an NPR Tiny-Desk-Concert. Aimed primarily at studio workers who have to live in them 8 hours or more every day. It's an ear-fatigue things so you don't blow your live overdub timing, or can handle doing a 3 hour long radio interview session.

When seen in *that* light, its what makes the K240 at first objectionable to us hi-fi'ers, but can be a cool thing to listen to once you know why the characteristics are the way they are. Perhaps not for long, but it's "trippy" to listen to your favorite tracks and pull out some weird stuff once in awhile.
 

600_OHM

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A funny misnomer - critical listening for guitar with K240's?

When I rock out, I like plenty of "crunch" in my electric guitar. That is, I like to hear it when closely mic'ed guitar strings are attacked so hard that you can hear the pluck just before the note. Esecially if one is doing a Townsend kind of thing.

If you listen hard enough with the K240's, you *may* notice that any initial plucks are muted or gone too, leaving just the notes behind.

This is the kind of "trippy" I find fascinating at times when using these. Usually I miss the crunch, and put my more accurate cans on. :)
 

600_OHM

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By what mechanism do you think they do this transient chopping? Or are they just a bit dull in the high end?
To expand on this a little more about reducing fatigue when I mentioned a "dithering" effect.

It's isn't exactly an FR dulling - if you listen to cymbals in real life, some of them have rivets in the edges to give them a "sizzle". Not all cymbals have these rivets obviously when a drummer doesn't exactly want sizzle!

Thing is, the K240 makes all cymbals sound like they have rivets in them. It's that studio-fatigue thing again. Almost purposely distorting this region slightly, cuz' you got 7 more hours of this to go before going home for the day. :)

I'm making too much of them. Just use the right tool for the right job.
 

solderdude

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But they did *something* to protect against things like gunshots in the studio.

step-k240.png


Above you can see the initial 'attack' is not removed nor are there any gunshots in a studio.
An indoor gunshot requires many, many dB's attenuation which the semi-open K240 simply does not have.

What one sees on the picture is an initial pulse is 'under-reported' by just 2 dB.
We also see a large dips following the initial rise (indicative of 'gritty' (not smooth) treble.
Subsequently we see a sharp drop-off after 1.5ms indicating poor bass extension.

Below the DT700 Pro X as a comparison.
step-dt700x.png


So nothing was done to affect a quick response. It just is the wonky frequency response that is responsible.
The dips between 1kHz and 6kHz are responsible for what you hear.
k240-fr.png

A small (not sharp but wide) recession in that area is actually welcome in a studio but this is too much.

Compare the K240 to several other headphones and you will see the frequency deviations are not nearly as severe in other headphones.
Only the really awful (and cheap) K52/K72/K92 are worse.
k240-comparo.gif
 
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600_OHM

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Ah yes, - the gunshots I'm speaking of is having to monitor say the small beach-landing segment of Saving Private Ryan for the 15th time on the actual recording for some feedback before corporate gives the go ahead.

Great explanation and charts - that really funky impulse response explains the grittiness, and combined with FR dips makes sense to me now. Seems like it was designed on purpose to be funky, rather than being a mistake or lack of qc.

I think that group delay chart on the rting site got me making a wrong assumption. Thanks for hanging in there with me to get my head wrapped around it.
 

Robbo99999

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I'll trust you on that. But they did *something* to protect against things like gunshots in the studio. Which makes these cans the absolute WORST thing to watch an action-movie with! Yawn.

And why many drummers really dislike these - those initial strikes are gone. Watch a well-timed video of a drum-solo, and you'll just about see the effect reducing the impact.

I think that's the missing groove of the K240 as a studio "tool", not a hifi can. - everything was designed like you were listening to an NPR Tiny-Desk-Concert. Aimed primarily at studio workers who have to live in them 8 hours or more every day. It's an ear-fatigue things so you don't blow your live overdub timing, or can handle doing a 3 hour long radio interview session.

When seen in *that* light, its what makes the K240 at first objectionable to us hi-fi'ers, but can be a cool thing to listen to once you know why the characteristics are the way they are. Perhaps not for long, but it's "trippy" to listen to your favorite tracks and pull out some weird stuff once in awhile.
I think the argument of ear fatigue is not totally valid, you're more likely to have less ear fatigue with a headphone with a well balanced frequency response that is free of sharp peaks - a headphone that perfectly followed the Harman Curve for example - that & not playing them too loudly if you're gonna be using them for hours at a time. This way you're not making compromises in audio quality and there is no fatigue. I think this K240 is just straight up a poor headphone with inadequate design, I don't really see them being particularly useful for anything.

(All your observations are described by the crappy frequency response, no need to chase after other obscure 'reasons' you mention.)
 

600_OHM

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If it was just a matter of FR alone, then I could see that.

But when you combine this with the impulse response, it seems to have reason. And as an owner, I heard this lack of an initial strike for years, but couldn't put two and two together. But that was part of my $job so I couldn't take them off.

At home a whole different story - I would never use the K240's for critical hifi.

What you are saying makes total sense, and I've even tested it.

I've worn the K240's at home to geek out on strangeness for up to 14 hours straight at normally elevated levels. And no audio hangover to speak of. I could make a phone call within 30 seconds of taking them off.

With other more accurate cans, I simply couldn't do it even at lower levels for more than a few hours. Not that they were bad, my Sennheiser 650's as much as I love them, just aren't the right tool for a 14 hour run! :) Sony 7506? Egads, not very long for sure, the sibilance which I'm sensitive to was killing me.

(note - sibilance and dithering/grittiness are two different things, but you know that. No sibilance in the K240's)

But yeah, I get why arminm barfed the first time he put them on. And maybe why you think they are inadequate based on specs alone. Not sure if you are an actual owner.

Many years ago when I bought my first pair (my boss wanted me to use some greasy worn out ones, so I went out to buy my own), I encountered a totally honest salesman and I asked him if he had some. He asked me if I was going to use them for home, or if I actually worked in some part of studio work. He was shocked to find out that I did, because most consumers just looked at "studio" and thought they were somehow better and reluctantly sold them when better choices for accurate hifi were around.

Trust me, they are purpose built and I'm not trying to justifiy them on something obscure. They are definitely old-school, back when "needs more cowbell!" was a thing. But I understand, to our hifi application, it can be kind of a shock.

But now that you know, get a pair and geek out on the strangeness once in awhile! :)

P.S. - don't buy counterfeits.
 
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solderdude

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most consumers just looked at "studio" and thought they were somehow better

Very common 'problem' indeed.
Some studio headphones can be used for music enjoyment though, most do not.
Some even love them to death and claim superior sound. The DT48 is such an example.
 

600_OHM

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Heh, for sure. Studio is so abused. Heck, when these were first introduced, what was their main competition? KOSS Pro 4-AA ?

But yeah, solderdude you are so right. I think Robbo's concern might be that I'll go out on a marketing limb like "If you're going to study the works of Segovia, then the K240 is it, because you won't hear the pluck, but just the notes!"

Yeah, right.

It's more like this for some period correctness:

If you want to get your groove on by listening to "Marshall Tucker Band - Everyday I have the blues" (on the 'tube, but be sure to listen to the vinyl submission)

You can do so ten times in a row with the K240's. Might miss a little crunch.

More accurate cans? Maybe one time will be good enough. I'm going to pull out the 240's, as innacurate as they are, and do that right now! :)
 

Robbo99999

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I personally think this is all a discussion about nothing in this thread over the last couple of days - it's all in the frequency response. I'm also not sold on such a frequency response being useful for anything, not that I work in the audio industry in any shape or form, and I don't see the argument of the frequency response of these headphones being "kind" to your ears. In my experience you want to minimise the sharp peaks to make them "kind" over long usage periods (which the K240 doesn't achieve) - instead I can wear my headphones for hours at a time without having any negative effects to my hearing (accurately Harman Curve EQ'd headphones) as long as I don't listen at my maximum listening volume.
 
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600_OHM

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That's a perfectly reasonable argument and I can't argue with your opinion. Ultimately, whatever turns you on. (revealing my age/era)

Studio - back when these were designed, meant for those in the know that not all studio work involves music. You could be blasted by a co-worker collaborating on cutting your 15th take of a war movie with 50-cal machine guns going off wondering if you need to punch up the vocals or not.

The problem arises that after the 5th take, your ears, even at reasonably low levels become de-sensitized, and now make a mistake by under/overcompensating the vocals. Here is where the dithering is a plus - you aren't striving so much for audio fidelity, but just getting the levels right.

I'm going to go out way on a limb here since this probably belongs in a different sub-forum here about science of hearing. Desensitization can occur if you hear things even at the right level with pure fidelity over and over long periods of time.

And here comes *my* personal opinion about AKG. The 240's are an extreme case, but I'll switch to the 712's and a kind of "house sound". To me, the AKG's house-sound seems more crafted for "long term" use, and not just the immediate measurements you take on a dummy head. There are exceptions and noted flaws of course. I could be totally wrong (probably), but my gut feeling is that *some* of their products FR are designed for long-term. Just a guess.
 

600_OHM

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Does it matter? As I'm writing I got the K240's on. I'm listening to my favorite stream / LPFM'er (KHUG rocks - classic rock by day, r&b/blues at night).

I'm up and dancing to George Thorogood to my best air-guitar. I should switch to my 712's, but there's no need - my invisible audience loves my peformance. :)

Boogie Children!
 

600_OHM

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OMG - I just realized that this test wasn't conducted with the AKG pads, but different brand velour. That DOES make a difference!

It's the first thing a "modder" does to tweak things - mess with the pads, and/or or the inner lining with different thicknesses of circular felt. Are those the "filters" you speak of in the 1st post? Heck, for filters, temporarily using toilet paper folded to desired thickness works too. But it's not what AKG wants. :)

Example: I have TWO of the AKG K240's - one at work, and one at home (the mkii's which came with oem velour). I wanted the velours for work, but decided to shoehorn some nicer appearing Beyers on them. DIFFERENT sound - actually worse than the oem AKG velour. So I bit the bullet and got the $$ AKG velours for this pair separately. Now the same sound signature from each.

I was bummed out because the Beyer pads were so nice! (The gray clashed with the overall akg "look", but I didn't care). But unlistenable. Mismatch of material densities and so forth.

Just so you know, if you take off the oem pleatherette plastic pads and look on the back they are totally solid and sealed. Guess what the AKG velours have? A singular hole in the backside.

The Beyers? If memory serves me right (been awhile) they had a bunch of holes in the back of the pad. Part of the problem is that with most of us balking at the cost of oem pads, we may be tempted to fit nice, but mismatched pads (say from Beyer) coming from the "these fit the following brands xxx -" Fit may be fine, but the material used actualy does matter.

So I appreciate this test - but unless one tests with the OEM product, like one would get if they bought off the shelf from a reputable dealer, some of this could be very misleading.

@amirm Please run this test again with off the shelf compenentry as supplied by the manufacturer. Ok, instead of barfing, you might just gag a little. :)

Otherwise, if we aren't testing with oem supplied pads, all we're doing is testing end-user mods.

[Update] - it's worse than I thought - but the other way around! Look at one 3rd party replacement pad for the Beyers state from the "LTYIVABHTTW" brand - at least they are honest stating that their pads will result in muffled sound due to increased comfort! KIDS - if you replace your Beyer pads, get the Beyers! They were designed for it.

I see what's happening here and why this review was such an outlier for me. Not totally off the mark, but not truly representative.

It's an easy mistake to make. I made the same mistake putting Beyer pads on my AKG 240's, and had the exact same initial response that arminm did with his pair that got submitted. Getting the oem pads, designed for the unit, brought back sanity.
 
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solderdude

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@amirm Please run this test again with off the shelf compenentry as supplied by the manufacturer.

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. :)
bold is my emphasis

Of course you do know I am all for experiments so I already did those tests :)

K240 Studio with stock pleather pads vs. K240 velour pads vs DT990 pads.

pads.png


versus Amir's measurements (Harman Corrected)
index.php


Very similar to my measurements (below) so quite representative despite the not original pads in this case.

K240 ASR style.png
 
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600_OHM

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Yep - my bad for skimming the 1st post, heading straight for charts. And thank you for doing the measurements.

In fact, it *was* the DT990 pads I put on. I could get them easily. AKG's - pita to find and buy. (Unless one did like I did and just get the MKII's)

Superior quality, (compared to some $6 sound-dude comfo-fit things...) But when I took them off, I started to think why let them go to waste - maybe I should pick up the matching Beyer headset!

Looking at the chart, one might think it would be a nice upgrade. But man, not for me. It placed the drivers further from my ears like I had 4 pairs of thick glasses on. :)

Back to the oem velours - I wanted them to tone down that hyped mid-bass as compared to the pleathers, which it surely did. Not so much for ear-sweat. But from looking at the chart say +/- 200 hz, one might not think so. Maybe more resolution to discern an actual 2db in the divisions. Heh, 2db on a chart vs 2db difference in your ears can be a make or break deal.

Testing arena - now this might be interesting - are the inner driver-liners oem or running bare naked or what?

Heh, some of my friends who bought nice Sennheisers started reading blogs and started the usual modder's intro of trying to "remove the veil" by screwing around with the driver covering - running bare naked, toilet paper, kitchen sponges with holes in them etc etc. Told them to take blog posts with a grain of salt. And remove the toilet paper from their Senny's. :)

Lurker reminder - I've never defended the K240 as a true fidelity set of cans. I use them for specific purposes.
 
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600_OHM

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OT: here a thought - reverse engineer a test by putting the AKG velours on the DT990's, and see what happens. Heaven or ouch? :)

Hmm.. speaking of mods - for the sake of science I might pop a hole in the back of the pleathers and have a patch-kit handy (or at least blue painters tape). I suspect that the hole is so that the velours are more easily squished rather than anything sonically tuned. Buuuut ... maybe a singular hole in the pleathers will bring down some of that hyped bass .. where's my bicycle patch kit? :)
 
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600_OHM

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We still have a slight problem. Scientific, not meant to be a controversial troll.

Solderdude - unless you and arminm are neighbors, the sound he is commenting on with end-user pads, and what you are measuring with real pads are different things.

Heh, the subjective (although I trust armin's ear) of end-user pads, vs the objective of your measurements with the real thing from the oem's.

I think some of the comments from non-owners may get this review confused between the two? Ie, worse than it actually is, albeit the 240's were never meant to be the pinnacle of hifi in the first place. It's why corporate put the kibosh on the sextets and their passive radiators back then - the cans were intended primarily for true general purpose studio use and not appeal to the hifi consumer. (often confused and mis-marketed today by everyone.)
 
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600_OHM

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Solderdude - you rock!!

Um, let's just say I found my reference for the drivers being wired "inverse in absolute phase" and some other fine details. Hello. :) Some other og's in the biz told me this was the gunshot protection trick when I brought this up.

Perhaps they were wrong. Either way I was blown away.

Suddenly my level of trust has skyrocketed. You nailed it man.
 
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