Pros: The best professional reference sound.
Cons: High impedance for DF, will break.
This review is dedicated to AKG K240DF and AKGK240 Studio headphones - for some reason Epinions have no distinction between several types of 240 series' models.
AKG brand name is usually associated with hi-end studio microphones and headphones. While they still produce variety of lower-cost headphones, K 240 is a high-end model capable of handling every possible task.
I've had K240DF for about ten years, and used it all the time. By the end they desintegrated - and I've had to buy a new pair. After such good experience with K240DF the only choise for me was K240. I've bought K240 Studio and now they're my horse.
Flat frequency response
This is what's it all about. These headphones have the flattest frequency response among all of AKGs, which means they don't boost or mute any given frequency range. What you hear is what it really is. Most of the headphones do not represent certain frequency ranges equally - for example, small sized headphones usually have no bass, and bigger sized headphones boost basses and highs to produce a more juicy and fat sound, which is good when you're listening to trance, but not as good when you work on mixes.
K240DF vs. K240 Studio
I've had no chance to A/B those two headphones. If there are any differencies in sound, they're subtle. Generally, everything I say here goes to both models except for two small issues: one is impedance which means also volume and the other is reliability: my K240DF is already broken while K240 Studio still holds on, and who knows, maybe it will last longer.
I think it should be a studio use. It is the best reference headphones I know. If you've heard Yamaha NM10 monitors (the ones with white speakers), you should know what we're talking about. Very defined, clear sound, without any "boom" and "hiss" typical to regular hi-fi equipment. If the mix sounds good on these headphones, it will sound better on any other system.
Don't have a record studio? That's okay!
Of course, if you're just an audiophile and not a studio engineer, you should love it as well. It is very sharp and you'll hear things you haven't heard before on the records you've had for years - just give it a try with your Pink Floyd collection, and you'll be amazed how many subtle things you've been missing. The major complaint I've heard from "ordinary people" is that it's not that much a*s-kicking and grooving as the other hi-end devices. As I already mentioned, you wouldn't get a "diskoteque" sound through with K240DF or Studio - try something cheaper.
First, K240DF have a very high impedance- about 600kOhm or something like that. It results in a relatively quiet output. If you just stick it into a "headphones" out of your computer, for example, the volume will be too low. It requires a preamp. Also, at one studio I had to record guitar while listening to playback through these headphones - they had only 240DF's in a room, and the volume was too low - they couldn't get it louder with their distribution system. For studio monitoring I would recommend K240M (Monitor) or 270M - they have lower impedance and are much louder (and they are designed for monitoring - according to the name). But, again, if you have a preamp, the problem does not exist.
I'm not sure but it seems like today K240DF is out of production. The new model I've got, K240 Studio, has a regular impedance, 55 Ohms, and there's no more volume problem I've had with K240DF.
Next, I'm not mad about the construction. Although it is comfortable and so on, I've seen better designs - Senheiser, for example, is lighter and fits the ear better. AKG is a bit heavy. I can handle three or four hours with the headphones on, but not more than that. I'm afraid AKG decided to keep the "original" design - people like vintage reissues, but I would at least put out another model with upgraded construction for those who want the same sound in a lighter package. It's also so big I cannot imagine someone sober plugging it to the walkman and going to the street.
Another construction bug (I've seen it on other AKG models too) is a big plastic ring on the outer side of each ear. It won't stay in place, jumping out and hanging on the metal frame connecting the ears. I've seen people using glue and masking tape to keep it where it supposed to be.
To make things clear - I don't want to say it's a really bad construction and so on, it is rather comfortable, but judging headphones of the highest class I would expect no flaws at all.
As I've said in the beginning of the article, K240DF I've had simply fell apart after 10 years of use. If you're from Netherlands it may serve you maybe 20 years.
Yes, it is comfortable - compared to many other headphones of the same price range on the market. The cord is long - about two meters (how many feet does it make? - no idea), which is a HUGE bonus - I hate short cords and I don't understand why other brands continue making them so short! The on-ear part is covered with leather, making the contact with the skin quite pleasant. Additionally, the speaker is not placed inside your ear, there's a small gap between the ear and the sound source, which makes the whole hearing experience more natural and easy.
Everything is very durable - sans the plastic rings I already mentioned. AKG headphones last years - just read other reviews!
Who should consider investing in a pair of K240DF's or K240 Studio's?
1. Studio engineers, home studio owners and all the musicians.
2. Audiophiles who listen to different sorts of music - not pop only.
3. Anyone who's looking for quality headphones for home use.
Who should consider different product?
1. People carrying mp3 players, walkmans, diskmans and such - AKG K240 is for home use only.
2. People who want to bang their heads with loud and punchy grooves.
3. Anyone without a headphones' preamp - if we're talking about the DF model.