I just recieved my new pair today. I immediately plugged them into my
amplifier and put on a CD. Almost immediately, I knew, these were good
headphones. I am used to using HD580's, so I did notice that they had a
'smaller' sound without the same fullness and depth to the sound as the
580's (especially in terms of bass.) But they are very clear, sweet and
balanced, detailed, and the bass is still satisfying. They are lightweight,
and comfortable (but not as comfortable as the HD580's which feel like your
not wearing headphones.) Overall, they are a tad brighter than the 580's,
and perhaps lacking in some range of frequency it can produce (I can hear
certain high-pitched sounds on the 580's which seems to be rolled off or
filtered on the 497's.)

How do the 497's sound with my IPAQ unit? Not that great. Sound is generally
clear, but seems to distort slightly at loudest volume. The sound is
brighter and somewhat harsher than I get out of my tube amp home setup. This
is due to the fact that these headphones are revealing of the source they
are connected to.

I think the next step for me would be to get a portable headphone amp to
improve my IPAQ's sound.