Summary: Overall these headphones are good, but without amping (which i suppose is not the headphones fault) they do not perform to their true potential.
The midrange is detailed, treble is reasonable but not super-distinct, and bass is slightly lacking.
Other than that they have a good sound stage, accurate tone, and sound very respectable. As far as vocals it doesn't get much better. There are worse headphones out there including some of the popular ones like Bose.
Summary: I'll give a quick overview of my thoughts on the 449's here, but if you want a full review, you can check out a complete breakdown here:
HD 449 Review
My quick thoughts on the HD 449 is that it has a decent sound in that it's tonally accurate as it has a very neutral sound. The bass, midrange and treble are all well balanced throughout the volume range but overall the sound just lacks that level of detail that gets you tapping your feet and nodding your head.
Summary: I'm not experienced in this field so I will mostly talk about the characteristics of the headphones that don't have to do with sound. But I will still talk about the sound as best to my abilities. I also would take my descriptions of the sound as a generalization rather than specifics because I said before I have little experience and would hardly call myself an "audiophile".
Pros: Great detailed sound, very modern looking, good isolation, feel solid in the hands
Cons: So far not good with all genres (especially ones with electric sounding instruments), padding feels stiff