Pros: Excellent spatialization (soundstage), tonality, flat-sounding, easy to mod, great looking
Cons: Bass is too attenuated and not extended below 40Hz, stock cable and pads are garbage
I thought about getting DFs as a present after passing driver's exams. Read those very few reviews online, which were generally a mixed back of helpfulness. Then I took the bullet and said, yes why not since I found a pretty good deal on ebay.de. I put them on and my jaw fell. The sound was so right, accurate and spot on, something I haven't experienced with any headphones before (K702, DT880, DT770, K701, K240 MK2). As the time passed, I sold most of my other HP as DFs superseeded them all.
The build is very similar to today's K240 Studios and MK2s, however DFs were made only in Austria, so all the materials seems sturdier, better looking and well made. My version came with genuine leather pads as well (no cracks), albeit fairly worn. DFs as well as Monitors do not feature miniXLR socket, the cable is securely soldered in.
Ah yes, the cable. It was only when I replaced it, the DFs came alive.
HA, caught you there Andy - you were audiophool and cable placebophile all along!
Not today Mr. Weasley. Upon careful examination, measurements and blindtests, the stock cable was found to be very noticeably altering the stereo image. First time that happened to me.
Fortunately, the remedy doesn't have to be expensive. I grabbed Van Damme Starquad for $2/metre, which I used before as mic cable and had great experience with. It was some work to fit it in there, but 2 hours later and my DFs were recabled.
Comfort-wise, DFs along with MK2s were among few headphones I could wear for hours without strain.
Now for the sound. DFs were marketed as "Diffuse field equalized to meet strict IRT specifications", and honestly they do sound like a near-field monitors in a small yet reverbant room. The spatialization aspect pretty much couldn't be better. It might not "impress" the listener as K701 do, certainly not on a first trial, but over time one starts to pick various elements in the stereo image much more precisely placed than with most headphones. The soundstage feels spherical, not excessively wide, retaining all three dimensions, especially depth. Elevation aspect isn't very pronounced, but still noticeable.
Trebles feel very natural and extended beyond human hearing range. Mids are right on spot, natural as they should be. Bass is there, not well extended, but controlled, not muddy, and plays very well with the rest of the spectrum, more so with acoustic genres.
The headphones are rated 600Ohm and 88dB/mW, which means you need an amp with lots of voltage reserve. Those who like it uber loud should aim for more than 6 Volts into 600Ohm.
For the rest of us, I found 2 Volts ceiling is enough to enjoy any sort of genre with enough reserve to boost quiet tracks. Most today's DAPs should handle 2Vrms into 600Ohms. For those which don't, O2 is a perfect remedy.
But even at just 1 Volt it's reasonably loud.
Overall the K240DF are one of the most underrated HP out there. I highly recommend anyone to give them a listen, possibly with different than stock cable.
I'll expand this review with more comparisons and photos shortly.