AKG Acoustics K240 Monitoring Headphones


New Head-Fier
I'll start off with the cons:
  1. They are large (not suitable for smaller heads)
  2. Hard to drive (600Ohm will do that)
  3. May be uncomfortable for long periods of time due to relatively thin pads
  4. Non-detachable cable
  5. May sound shrill to some because of bass roll-off and bright treble
That's the cons. That's all of the cons.
I've heard headphones above and below these in price, but none have matched the open, precise soundstage, clear definition of sound and sheer amount of detail in these beat up old cans. The cable died a couple of times, the pads had cracked due to age and were replaced. When I replaced them, I tried to find something as close as possible to the originals, to preserve the sound signature. They are still uncomfortable for long usage and I still don't care.
If I would ever consider writing a love letter to a pair of headphones, these are the ones. I probably wouldn't have the heart to tell them they have any cons, and certainly wouldn't start with it.
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500+ Head-Fier
Pros: Wonderful mids, comfortable, realistic sound, pretty good detail
Cons: rolled off bass, small soundstage, can be sibilant sometimes
When I compare these to the newer Studio K240s, these win by a long shot. Not only in neutrality and detail, but in build design too. 
The Studios have a big mid bass hump that makes everything sound boomy. But the Monitor version has a very balanced frequency response that sounds almost perfect. To me, the treble is very good, but I dislike the spike most AKGs have in the 8-9 kHz range, these included. Although not as apparent with classical music (which these are great for btw), rock and pop and singing definitely is sibilant after a while. That being said, the treble adds to the detail retrieval, which may be why these are meant for studio monitoring use. I also LOVE the mids on these, and they are the phones strong point. Mids are better than the HD 600s IMO. That being said, the soundstage is kind of small compared to many headphones, but still ok. 
I also have noticed the bass could be a little more, as it rolls off quite a bit in the sub bass.
EDIT: 6/3/14
I have tested these with both the ODAC+O2 combo and my vintage Nakamichi TA-2A + CDP-2A. Sounds amazing with both of course, but I prefer the Nakamichi as it powers it better and gives a little extra bass boost and it also smooths out the treble a bit. It's also meant to be driven from those kind of sources. With the ODAC+O2, its a little sibilant and bass could be a little more, but this is because of the neutrality the O2 brings. This headphone would do quite well with warm dacs and amps. 


New Head-Fier
Pros: comfort, aesthetically pleasing, non fatiguing sound , cheap , readily available, well built. great value
Cons: shallow earpads, slight lack of sparkle in treble, bass could be tighter, 600 ohms is hard to drive
I was looking for a studio monitor headphone for under a hundred bucks, I was going to buy the AKG K240 Studio at first but saw these "Monitors" on eBay for much cheaper, for 59 bucks I didn't hesitate to buy them although I was nervous about the 600 ohms impedance. They arrived in perfect condition with the elastics still having lots resistance, and the ear pads without any cracks, however the golden labels at the sides had fallen off (common issue). I hooked them up to my HK 3490 receiver which were being fed Apple lossless files from my computer through my uDac 2. After three minutes I was ready to return them, everything was muffled, mids, treble, bass, absolutely terrible. I was curious, and took off the earpads and the filter, what I saw shocked me. Literally half an inch of this strange dusty, black residue gunk was everywhere, it covered the six circles around the driver and was also on top of the actual driver, I think this was the dried up residue of the adhesive they used 20 something years ago to attach the cloth to the plastic. After giving both sides a thorough cleaning and dusting out the filters, they had transformed into something else. 
Bass- It's there, reaches quite low but isn't too emphasized and can be muddy at times, but not terrible at all. I listen to lots of bass driven music (rap, electronic) though I wouldn't call myself a basshead and I'm quite satisfied with the bass these put out.  
Mids- What these headphones excel at, a bit forward but never fatiguing, very clear and detailed, upper mids could be better. 
Treble: The reason why these headphones are never fatiguing is because of the rolled of treble. The lack of sparkle in the treble gives female voices a sometimes "dark" sound, I myself don't like a treble assault on my ears with headphones so I don't really mind this as it lets me listen to them for a long time but for you that want that pronounced treble, nothing a bit of EQ can't fix. 
Soundstage: Excellent, I can distinguish locations of instruments in live performances, and also where people are firing at me from when playing Call of Duty 

Comfort- I love the self adjusting headbands on this, not a lot of clamp, however these won't come off your easily, I have a slightly large head and these fit me well, I often forget I'm wearing these. I just wish the earpads were deeper and had more cushioning, my ears sometimes press against the drivers. 
Build Quality: Excellent, headband is solid, plastic used is sturdy, gold accents give it a sense of quality, leather is also soft on the ear pads, besides if these weren't well built how could they have lasted 20 something years?
Aesthetics: One of the greatest looking headphones ever made. 
Design- Are you kidding me? The K240 series is one of the most famous and successful headphone series' of all time spanning five generations: Sextett, Monitor, DF, Studio and MKII. 
Bang for the buck- $60 bucks for this type of sound quality is unheard of, even if you pay 90 bucks these are still a great deal.
Overall: A solid choice for a used, cheap monitor. After 30+ years, the K240 is still a studio standard.
Bass- 4/5     Mids- 4.5/5      Treble-3.7/5       Soundstage- 4.5/5      Comfort- 5/5       Build Quality-5/5        Aesthetics- 5/5        Design-5/5      Bang for the buck- 5/5    Overall- 4.5/5 
nick n
nick n
that dust used to be the foam layer that was attached to the cloth, go grab some new inserts to get it sounding back to stock. The foam needs to be there and will affect the final sound. Thanks for reviewing these! ( have some also )
Got mine on ebay too. Sounded horrible at first so I took them apart because I was able to get them for $40 and figured if anything I'd just be out $40. Once everything was clean.... damn. I was amazed. I went to ace hardware and bought some window unit ac for $2.50 foam, cut circles out, and stuck them between the pads and the driver after getting all the gunk out. I find the bass a bit lacking for rap and edm, but metal sounds fantastic. Didn't go all Call of Duty, but Battlefield with these is better than my virtual 7.1 G930 Logitech headset.


100+ Head-Fier
Pros: light and comfy, sound nice when amplified well, looks good
Cons: Needs lots of power, thin flimbsy cable, head sweat
Got a deal on some of these 600 ohm out of stock beauties in mint condition and am about 3 hours into testing them. So far I am pleased with the quality and fit. Got mine hooked up to a Musical Fidelity V-can so there's no worries about power. When i first got them I hooked them up to my iphone and could barely hear them, even with the volume all the way up. I then realized how much more is needed for these and why they took the next generation k240's down to around 55 ohm. Once i burn them in I'm sure they will be a good casual listening can. Anyway, i couldn't pass up a good deal.
Why 600 ohm? Well I'm sure there's a reason to get them if you find some. I finally got my V-Can to near 11 o'clock, where it's normally at 9 o'clock or less with my AKG K701s. I think there's an advantage to being able to turn them up like hearing more of those imperfections when listening to studio mixes, hopefully not just for a future deafness. So far they are nice and nothing stands out in the lossless files I listen to, though I do like to give them a little EQing on iTunes which they seem to benefit from. Though they are not extremely bass heavy at any setting, I feel like I'm getting more of what was expected from those studio recordings.
Sweat is a small factor during long listening sessions with these. Also, can't imagine why they use a 3.5 mm plug, though my V-Can has a 3.5 mm output so it has worked out very well. I want to a-b them with my other headphones, but at the volume levels these need I will have to just listen for some time with them and then with the others I have in order to hear what I may be missing. I'm sure I'll always love my Yamaha YH-100 orthos the best of all my cans, and I don't really need these except as a throw around headphone, but we'll just have to wait and see how they burn in.    
I agree, the K240 is slightly bassier than what neutral would be. Makes for nice relaxing listening and no bass boost needed.. Terrific value for 50$.


500+ Head-Fier
Pros: Works good on vintage receivers; solid bass, medium resolving, a bit less than medium soundstage, AKG clear vocals
Vintage headphones AKG K240 600ohm, would buy again.
Hi, may be you try the K240 DF and compare again....! I guess it will fit much better to the Sennheiser HD 600 benchmark.
BR heinz
abby normal
abby normal
they've been around for a long time, I wish there was an audio store close to me so I could compare them to my senn hd580s.


New Head-Fier
Pros: Great sound and comfort, AKG service
Cons: A little hard to drive (600Ω)
Of my three AKGs (K271S, K240M, K280), those are my favorite.
They are very comfortable and also smaller and lighter than the closed-back circumaural AKGs. Being 600Ω cans, they are somewhat dependent on the source: My old JVC CD player drives them well, so do the powerful headphone amps of older mixing boards. With less powerful outputs, e.g. digital pianos, they work ok, with portable equipment not so much.
Their sound meets my taste for general listening very well. Overall they are balanced and pleasant with reasonable attention to detail. Bass isn't as recessed as e.g. on the K271 - for listening that's a good idea IMO. Also, they lead to relatively little ear fatigue, although the don't match the K271 in that respect.
I was surprised to learn that although it is semi-open, the K240 Monitor is very dependent on the condition of its ear pads. Flat pads impair sound quality and comfort, as the baffles tend to touch the ear. Also, the new velours pads from AKG pretty much destroy their sound - so it's a good idea to stick to the leather pads, they're cheaper anyway.
As it seems to be a general consensus that those are great phones, it's hard to make a real bargain unless you're very patient on eBay. Also, it makes sense to replace elastics, ear pads and the foam disks on the baffle right away - it really makes a difference in comfort and sound.
Anyway, considering that I paid about €60 for my unit, it is a fair price for cans that serve as workhorses and for relaxed listening as well. As I said, of the three AKGs I have, those are my all-time favourite.