First, they're low impedance phones (12 ohms) and although you can drive them from portables, they really want plenty of current to sound their best. Second, they're very, very sensitive to placement on your head and over your ear. There's a sweet spot for the best bass response. The bass is not very deep, but it is well balanced, detailed, and fast. They sound very much like loudspeakers and not headphones, and image very, very well (many binaural enthusiasts rate them as one of the top two cans for those recordings). The top is smooth and delicate. The midrange is prominent, pretty good but muddy when compared to better phones.

They don't come close to my AudioTechnica ATH-W100, but few cans do (we're talking another $200 over the Sony's. I think the F1 is far more listenable than the cheaper Sony V6 in the mids and highs, and even though the bass is lacking by comparison, I'd take them over the V6 any day. You can use them with portables, too. You can get used to the sound quite easily, and wear them for hours and hours without any fatigue. Worth trying, IMHO. But they're not the usual set of headphones.