AKG Acoustics K-240 Semi Open Studio Headphones


New Head-Fier
Really disappointed, I regret buying these
Pros: The 240s heritage from the 70s, the looks
Cons: Non existent bass, muffled overly emphasized mids with not enough detail and extension on the highs, they sound dark and fatiguing in the mids, uncomfortable fit around the ear, mediocre soundstage, imaging and bad separation of instruments, build quality is also really bad
I had listened to the 600ohm model in a studio which I .liked and I decided to get the newer model, but I was really disappointed with the bad sound quality compared to the old model and other studio headphones. They sound lean . very thin and everything you mix with them turns out bass heavy because the have really poor bass response and non existent subbass, opening the cans made of the cheapest quality plastic I was surprised to see very tiny drivers inside the big empty plastic can. They are not flat at all, The hype about their "magical" midrange is just that, a marketing hype, they have no bogy in the mid frequencies, but that are overly emphasized (since there isn't enough bass and high frequency presence) the vocals sound thin compared to other cans and have not good enough detail, hearing classical music you will have a difficult time to hear each instrument clearly, they are also really bad with electronic music and rock. There are a lot of headphones in the same price range that sound way better than these. so take a listen before you buy! Lastly the build quality is awful, they feel really cheap.
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100+ Head-Fier
Pros: Lightweight, very comfortable, superb audio quality, spacious non-fatiguing sound, wide soundstage, great imaging, detachable cable, removable earpads
Cons: Design is not for everyone, too cheap for what they deliver :),
These cans are really, really good. Highly recommended.


100+ Head-Fier
Pros: Warm sound, good mid, cheap price at $70, easy to drive compare to others
Cons: bass is boomy, and slow, but still way better than Dr Dre's headphone.
Warm sound, good mid, great price
Easy to drive compare with other studio headphone, there is shouldn't be too much complaint consider this headphone now only retail about $70 and sound really great.
If you find 240s to be boomy then best of luck with your quest to find a perfect headphone !


New Head-Fier
Pros: Clear Mids, Tangible Highs and Subtle Bass
Cons: You will start to hear the difference between MP3 and Flac.
Having owned these headphones for roughly 6 months I must have accumulated over 1500 hours with the K240s on my head - that will give a hint of my opinion on them!
- Sound quality is a definite step up from most consumer headphones; after owning these I don't settle for anything less.
- These headphones are completely non-fatiguing wearing these for hours at a time is a breeze.
- Comfort is surprisingly good; the pleather cups can leave a bit to be desired after about 5 hour or so but other than that they are great.
- Overall good build quality, although the headphones are mostly plastic I have dropped them a few times and they didn't suffer any damage. Look after these and they should last years.
- Detachable cable a definite plus. Furthermore, the cable is of a gauge that it wont break if it gets caught in a door or something!
- 196Kbit/s MP3s wont cut anymore with these. A good source also does make a difference (I run mine through a DigiDesign 003 Rack).
- Although these headphones are rated 55Ohm impedance; those with a love of low end bass will definitely appreciate running these through an amp.
- Poor sound insulation/isolation is not great. Obviously with these being 'semi-open' headphones wearing these on the bus is a no-no.
- Something a didn't think of before I bought these is that coming from closed headphones I did not appreciate how wind creates whooshing noises when you listen to them outside.
- The large earcups will turn heads in a public place (not in a good way). These are not beats, wear these for the music not style.
A great headphone for anyone looking to get into the headphone club; I don't feel embarrassed when mentioning I own these to sound engineers or producers. The headphones scale well with better source equipment/amps. I bought mine for £50/$85 and at this price I think they deserve 5*.
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500+ Head-Fier
Pros: Custom-tailored frequency response contasts notes better, meaning, they're easier to play in. Which is why they're often used for playing synths. Also very useful for sniping dirt in samples and fine-tuning mixes.
Cons: Awful stock cable.
AKG K-240 Studio are at least the 4th (really 5th or 6th?) iteration of K-240 design, which started with the K-240 Sextett in the 1970s, themselves a circumaural version of supra K-140. The basic idea behind the "Sextett" design is that the main diaphragm drives six passive radiators, which enhance ambience and spatial imaging. Now, while this is a very good idea for headphones in an era when most headphone amps were powerful enough to drive 1200-ohm and even 2400-ohm headphones, unfortunately modern amps have not been able to keep up and thus the K-240 and K-271 have a reputation of being power hogs. Really modern device (cell phones', pocket players', netbooks'...) headphone outputs are too weak and lame though. They're still efficient enough to be driven fine (thoughly slightly weak) by most Apple players.
Classic K-240 (Sextett, Monitor, DF) are all 600-ohm. The K-240 Studio are the modern 55-ohm version, lower impedance, higher efficiency. While they work with anything, really they have lost some of the smoothness of imaging and stability that 600-ohm offers. Still, they can be driven by pretty much anything nowadays. The only issue is that weaker pocket players and notebook PCs won't be able to drive them to fullness. They work just fine with any professional gear though, which is what they're meant for.
Make no mistake, the K-240 Studio are designed for use by musicians and sound engineers. Which is why they have a frequency response which is not straight by definition: midrange is raised to improve note contrast and show details in recorded takes, mixes and samples. It is not carelessly lifted though, and the K-240 still manage to have a very musical and rather natural sound signature, unlike their sibling the K-271, which has a weird treble/midrange transition and an overall melancholic character. The only advantage the K-271 Studio have over the K-240 is being fully closed; if you're trying to choose between the K-240 and K-271 for listening to music, go for the K-240, they are warmer and more natural.
Sometimes the K-240 are said to have a "sloppy bass", but this might be more an issue with amplification (the K-240 by design are not very efficient, having passive radiators that are driven by the main diaphragm too). The K-240 Studio are not designed as a boombox, but with the right amp they can deliver a lot of low-frequency power and massage ears with just about any kind of music, as long as it has low frequencies.
High frequencies can feel a tad too rolled off, but really this is a design decision as it seems AKG decided to roll some K-240DF properties into the Studio design too, bringing the overall frequency response closer to the DF model, while still keeping some HF response. As a result the K-240 Studio can sound darkish at times, but they're still sparkly and 3D.
Where the K-240 Studio really shine is space definition. As an example, stock-cabled Denon AH-D1000 will play a rock piece with the guitar in the centre, bass right next to it, and drums in the background, the singer floating in mid-air. In K-240 Studio, this same piece plays with the guitar in the centre-sides, bass separated better and tugged to the back, and drums panned all across the soundstage. The soundstage is quite large, and it's defined rather well to any side, even vertically. The K-240 like to separate instruments and pan them properly. This might also be an important quality for any classical music listeners.
The one big flaw of the K-240 Studio is the stock cable. Some say it's made of leftover old scrap copper, and to tell the truth, it sure sounds like that. The stock cable just won't make the K-240 show all they're capable of. Too dirty, too many stuck harmonics, too dark, too slow, bass and high frequencies slightly falling apart in the time domain, and of course, the delicate high frequencies get lost too, simply because the stock cable is not shielded. To make K-240 Studio show what there really is in a record, you need a good headphone amp (or output; a stationary stereo system amp will do, as will a mixer, a good pro sound interface, etc.) and a shielded high-quality cable. Shielded high-purity copper is one option, but they really become accurate with a shielded silver-plated copper cable.
Dynamics are slower than Denon/Foster headphones, but still quite good. K-240 aren't as fast, but they still paint with a good accuracy. They could be a bit sharper in dynamics, but with a silver or silver-plated copper speed/response is improved.
K-240 can be used for mixing, though really they're mostly for "zooming in" on parts of the soundscape and discerning details that are not as clear on speakers. They're very helpful when cleaning up samples and microphone takes. Like a "magnifying glass" for sound. They also work fine for monitoring. Don't let the "semi-open" bit fool you - even a singer in front of an LDC won't let music bleed into the microphone. A producer friend uses the K-240 Studio for singers in front of his C-414. They might bleed something when cranked up way too high (which is difficult), but in practice they're fine for any kind of studio work, though frankly closed headphones are still better for monitoring microphones, as they block more external noise. On the other hand, you can have radio talkers hear each other "live" and their own voice without taking off the headphones, which might be a downside or a plus.
The K-240 are built tough, from a dense plastic that's guaranteed to hold (mine once got bumped by a moving car). The "Studio" name is really appropriate, they're studio gear meant to last.
Overall, highly recommended. This is a must-have for anyone who plays synthesisers, edits sound, composes music, and mixes. Just recable :)
I have the AKG K240 MKII and I agree with you on the cable being junk, I found simply going from the straight to the coiled cable on the MKII changes the sound, it sounds fuller and less harsh on the highs with the coiled cable. Bass and highs seem better and more defined, the bass comes to life and is more present but also it doesn't interfere with lower midrange like it does with the straight cable. I'm curious what a better cable will do. I'm planning on a buying a high quality shielded copper cable. I found this review helpful and I plan to buy a better cable as soon as possible thanks to this review.


New Head-Fier
Pros: Perfect sound, nice fit, comfortable.
Cons: Not really a fashion item.
A complete no brainer: if used at home probably the best headphone you can buy for this money, they fit comfortable and have excellent sound. There are better sounding headphones out there but you have to reach much deeper in your wallet. 
They are not suited for travelers in my opinion.
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These are great headphones that I could easily live with if my budget was tight.


100+ Head-Fier
They didn't cost me an arm and a leg, but they sound great!
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100+ Head-Fier
Pros: Great soundstage, price, and comfort. Rock rocks with these cans.
Cons: Elastic headband adjusters, pleather. Loves burn-in like a fat kid loves cake.
I got a free $75 giftcard for Walmart and decided to use it online to get the best headphones they have since there's nothing else I really want from Wally World.
The best pair happened to be these K240s.
The K240s are the type of headphones that really appreciate a good burn-in. I see it almost as a test of worthiness.
Previously I wasn't the type to do burn-in as my Sennys didn't really benefit from it and it always seemed like superstition anyway. Upon my initial listening tests of the K240s I was rudely introduced to what many term "recessed mids", and underwhelming bass. I immediately felt that I needed to list these on eBay and rinse away the muddy memories the K240s left in my head, but being the hopeless romantic that I am I continued to listen and dream of better sound.
Over the course of 1 week with passive burn-in I've noticed that the K240's sound signature actually warmed up. Did the religion of burn-in have a deity that was kindly looking upon me? Yes, there is a burn-in god. The bass is FANTASTIC. It is responsive, punchy, and most importantly doesn't drown out the mids or treble. Even the mids started to pop up from the recessed hole they decided to hide in. I'm about 20 hours into a passive burn-in (I don't let them burn in over night or while I'm away, it's all done whilst listening) and I can't wait to hear what another 20 hours does.
Sure, you can get more expensive, better sounding headphones, but if you're a broke college schmuck (such as myself) the K240s fit into a tight budget. Also, at 55 ohms they don't require an expensive amp, but don't be mistaken, they do benefit from amping. I'm using a Qinpu Q2 to provide some extra punch and some tube sweetness.
The cons are typical of the materials used. Pleather is almost never a good idea so why would it be good now? As for the elastic headband adjuster... well... I can't wait for that to break/dry rot/stretch out. *sarcasm*. With that said they are still very comfortable and right now as I'm listening to Rage Against the Machine (Rock, in general, sounds amazing!) I can hardly feel that they're on my head. The cans seem very sturdy so I won't can't really complain too much about the materials.
In short, the sound is a happy medium; not too much bass, not too little bass, mids are happily present, and the treble is very respectable. These would fit the preference of Goldilocks, they're just right.
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