Some quick impressions between the HFI-2400 and KH-K1000:
The KH-K1000:
- Is "smoother" and less aggressive sounding.
- Is more closed-in sounding (it has a very "intimate" soundstage; very 3D but not huge)
- Is balanced, despite being able to dig very low (and hit rather hard)
- Is mid-centric and somewhat slow (admittedly compared to nothing but open-back cans and stats)
The HFI-2400:
- Is a bit more aggressive, but not what I would call harsh, on the top end
- Has pulled back mids
- Has much more mid-bass energy, to the point of sounding somewhat bloated
- Weighs much less and has velour/fabric pads (it will probably be a better pick for very long-term wearing; I think my record on the K1000 is around 7 hours)
Overall the KH-K1000 is a better choice if you're listening to music or want something more accurate, but the HFI-2400 is more "fun" for games and movies, and costs a lot less. Both can very well do 3D (neither is a K701), and both can pull a lot of details out (the K1000 is probably a bit better, because the mids aren't recessed relative to the rest of the spectrum), and both are very suitable with videogames and movies. I would regard the K1000 as the more conservative choice, sound-wise, but the HFI-2400 as the more pragmatic choice, price-wise (in other words, if you only have $100-$200, want a decent amount of bass, need to wear these for a long time, aren't critically comparing them to everything under the sun, and are okay just buying something and leaving it alone; the HFI-2400 are probably not a bad choice).
They are quite different in their overall "flavors" - the Kenwood is more of a jazz/trance affair (lots of mid-range energy with a healthy amount of bottom-end impact and top-end extension), while the HFI-2400 seems best suited for grunge rock or something along those lines (lots of low-end energy without destroying the mid/high-end energy in the process). The biggest downside I see to the KH-K1000 if you're in the States, is that you can't return them to AudioCubes if you aren't happy with them (and they probably take a hell of a beating on resale due to their rarity); the HFI-2400 on the other hand are available from Amazon and other retailers that have a return policy. If you're on the fence between them, I'd honestly suggest the HFI-2400 - if you're not happy, send them back and try again (perhaps the KH-K1000). With the Kenwood on the other hand, once you've got them, they're yours - for better or worse (they're really quite pleasant though, and I honestly couldn't see too many people disliking them; they contrast WILDLY with my general preferences for a headphone (they weigh about twice as much as any other can I have, have about a gazillion times as much bass, are closed, etc) and I don't see myself getting rid of them any time soon).
