The original K240 headphones by AKG were introduced back in 1975 and they had an impedance of 600-ohms. I remember plugging in a set and hearing low volume and weird frequency response. My friend and mentor, Dr. K made my brother an impedance matching box with some transformers he bought at a surplus shop. I was struggling to understand transformers at the time and was amazed that a regular 1/4” headphone output, on my fathers Marantz receiver could drive the somewhat large pair of transformers, which brought these headphones to life without external power. Times have certainly changed, meet the MK II, K240.
The AKG K240 MK II has been a staple in professional audio circles since its debut, and even in 2025, this semi-open studio headphone refuses to fade into obscurity. As someone who's listened to countless headphone sets over the years—from flashy wireless cans to high-end planar magnetics to printed-ribbon diaphragms, and all points in between — the K240 MK II stands out for its enduring place in the market. It's not trying to wow you with bass bombs or spatial audio gimmicks; instead, it delivers reliability for mixing, tracking, or just listening at home. Priced reasonably, today’s K240 MK II is an audio gateway from an old name in professional audio.
AKG was acquired by Harman International in 1994 and starting around 2013, production in Austria was slowly suspended and eventually moved to China where the set in this review were produced. The K240 MK II headphones were first introduced in 2008 and since that time subtle changes and improvements have brought us to where we are today.
LIKES
- Mini XLR (industry standard connector) used to attach cable
- Extra cables included
- Extra ear cushions included
- Very light weight
DISLIKES
- The frequency response
- Lack of bass definition
- Lack of bass
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FEATURES |
DETAILS |
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Design |
Semi-open over-ear with self-adjusting leather headband and velour earpads for extended comfort |
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Impedance |
55 ohms |
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Sensitivity |
91 dB SPL/V |
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Frequency Response |
15 Hz - 25 kHz |
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Driver |
30 mm XXL transducers with Varimotion diaphragms |
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Weight |
240 g (without cable) - about half a pound |
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Cable |
Detachable mini XLR; includes 3m straight and 5m coiled cables, with convertible 1/4" to 1/8" jack |
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Sound Signature |
Colored, with slight emphasis on mids and highs |
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Sound Stage |
Sounds narrow and slightly out of balance from left to right |
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Isolation |
Minimal passive isolation due to semi-open backs; not ideal for noisy environments |
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Price - 2025 |
Approximately $80-$100 USD |
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Best for: |
Studios, home audio enthusiasts, and budget-conscious mixers seeking an industry-reference sound |
Whether you're dissecting a vocal take or unwinding with a jazz record, the comfortable and easy to use K240 invites you to listen. A classic brand name, solid build, versatile accessories, and a relatively low price make these headphones an easy purchase in 2025. Consider exactly why you’re buying so you don’t regret the purchase.
In the studio I’d never choose these for the bass player in the band but guitar players might appreciate the relatively steep roll off in the low frequencies below 100 Hz. I often insert a 100 Hz Hi Pass filter on electric guitars when mixing, this makes the guitar sound brighter without adding any boost. These headphones already have that cut in their natural frequency response.
EPILOGUE
In a market flooded with over-engineered gadgets, the AKG K240 MK II reminds us that sometimes the classics endure because they simply work. If you're building a studio setup or upgrading your listening rig on a budget, these headphones would not be what I’d choose for making mix decisions. The lack of low frequency reproduction is not revealed by simple frequency response numbers, seek out independent testing and you’ll see what I’m talking about. The K240 MK II are nowhere near flat response, which is what I've conditioned my ears to value the most.
Thanks for reading High on Technology, GOOD MUSIC TO YOU!
©September 2025 by Mark King, It is NOT ok to copy or quote without written permission from the author.
SPINAL TAP
I was watching this 1984 classic recently and noticed that in the recording studio scenes (which were shot in a real recording studio), they were wearing AKG K240 headphones.
STEVIE RAY VAUGHN
In March of 1988 I got a call at my downtown pro audio shop, from Stevie Ray Vaughns tour manager, he wondered if we had a headphone system that could be used in their bus. I dismantled the system in use in our store’s recording studio, pulled out the main components (three custom made stereo headphone stations, a pair of 100 watt - 4Ω power resistors and the connectors and cables). I drove it over to the Fox theater and met with the stage manager. He paid me for the system and gave me two fifth row center seats for that evening’s performance. He told me they were using AKG K240 headphones in their bus.
ONE MORE THING
I’ve really enjoyed this journey reviewing my collection of popular headphone models (found in recording studios of all sizes). I’ve definitely developed a new opinion by bringing all these headphones together in one place and A-B testing them against each other with premium headphone amplifiers. There will be a wrap up article that will attempt to pull all this data together. Coming Soon!
Now, go get your headphones out and USE THEM to create something beautiful. . . . . . .
