I am soon to be the owner of a pair of 580's and I was wondering what I could expect in comparison to my e3's for home listening. Do you think this would be considered an upgrade in sound or is it too tough to compare these since they are somewhat radically different?
i have not heard the 580's but i had the e3's for a few months before i sold them to get the e5's.
i will try to offer a bit of general knowledge comparing headphones and canalphones ~ 580 - e3.
the most immediate sonic difference between these two phones will be the sound stage; the size of the area the sound appears to be occupying.
when you compare an in-ear canalphone to a full-size headphone, it is to be expected that the canalphone will sound more "enclosed" and in your head; where the headphone will seem to "surround" you more. This is not necessarily a good or bad comparison, but more so just an observation of difference.
the other thing is the bass reproduction. it is usually expected that a full-size headphone will have more bass than a canalphone. while there are some canalphones (e5's, Pro 2X's and ue 10's, all of which cost over 500 dollars) that have great bass that does in fact rival that of a full size headphone, i can safely say that the e3's do not. you will definitely get more bass out of your 580's then you will out of your e3's.
your initial question is a bit impractical to answer, because you are comparing two very different phones. i understand your inquiry however, as you are new and would like to acquire some general knowledge about headphones. as you spend more time here, you will begin to realize that what you are looking for
is the most important thing. this can only be discovered with personal listening experience.
you will also learn to trust certain people's opinions as you read posts throughout headfi, and realize certain people share your taste in sound.
anyway, welcome and good luck finding a pair of headphones that suit your needs.