Pros: Great bass, Satisfactory mids, Good Isolation, Looks, Build Quality, Screw-on 1/4 inch adapter
Cons: Bright treble, Pleather quality, Clamp pressure, Sweat prone, Headband discomfort
note- I actually have the Ultrasone DJ1 but since they're essentially the same as the HFI-580 (For those that don't know, the DJ1 is the same headphone with a different colour scheme / logo, and a coiled cable), I decided to post the review here for more exposure.
I bought these phones to compliment my Grado SR-225i as a sealed headphone for more bass-intensive music like electronic and hip hop. These phones are pretty hyped around here, many people quoting them to be a basshead's headphones. This might be true for you depending on what you consider basshead to mean. If a basshead, to you, is 'I WANT MOAR!', these have potential because you can EQ them to be very bassy, but they will disappoint you out of the box. If a basshead, to you, is someone who likes some bass emphasis but more importantly great bass quality, then these should be quite satisfying for such a budget.
The headphones are quite sturdy, the plastic and metals used feel and look quite tough. It's also quite a good looker, it's much nicer in person than in pictures (but that's almost always the case for me). I like that it uses a screw-on quarter inch adapter, I think they're unendingly superior to the regular clip-on variety. The headphones isolate well, too, so they fulfil that purpose if that's important to you.
The bass is definitely the stand-out in the sound department of the HFI-580. It's tight and well defined, with good punch. It does have a mid bass hump, and rolls off moderately into the low sub regions, but I find that deep bass is represented quite satisfyingly, just not as in your face as the upper bass. I find the bass to bleed very, very little (if at all). It knows it's place. The mids are as reported, recessed, at least compared to something as mid centric as the Grados. They lack flair and the rich tonality of the Grados but they're hardly of poor quality at this price range. They just take a slight back seat in comparison to the bass and aren't quite as rich as I'm used to. Female vocals sound further back and a slightly buried in comparison, but the mids are definitely satisfying overall. The treble is my real gripe with the sound of the HFI-580. At times they manage to make the Grados sound almost conservative in comparison. The Ultrasone's can be hamfisted with the treble, which isn't an issue (if not beneficial) for dark recordings. However for bright recordings it makes the music far too piercing and shrill. Sure, the 225i's are trebly, but the airy sound of the headphone makes it sound considerably more natural (and therefore less fatiguing) than the HFI-580. It's simply too bright a headphone.
I have a few design and material issues with this headphone. The pleather they used is not good quality. It's hardly the worst stuff I've ever encountered, but it went hard very quickly for me. It's nice and soft to begin with and it feels relatively thick which was a good initial sign but noticeable hardness started setting in after a fortnight. My significantly cheaper Sennheiser HD448 (which I used for 18 months before selling it off) stayed as soft as the day I got it. Now, sure, you could argue that the earpads are replaceable so it's not an issue. I'd agree if it took a year or two for it to go hard, but for the affect to start setting in so quickly is disappointing. Don't get me wrong, it doesn't make the earpads unbearable but it's simply not nice to feel on the skin, and once they harden they're prone to cracking. The same phenomenon occurs with the padding for the headband, which uses the same pleather as the earpads, however there's no headband padding replacements available. Whilst I haven't tried this, I would suggest attempting this headband modification (for both comfort and durability): http://www.head-fi.org/t/579875/comfort-mod-hd650-headband-padding-on-the-pro-900
Speaking of the stock headband, I dislike it. It's a generic design (I've seen the identical design used on some Beyerdynamic headphones such as the DT660). It's uncomfortable, putting all of the pressure on a small area of the head with a small, stiff rectangle of padding (I was unpleasantly surprised at how hard that headband padding was out of the box). I'd also say the headband is the weak point of the headphone aesthetically. My ears also get quite sweaty in the earcups. If you live in a very cold area then you should be able to avoid it, but once it gets anywhere near the mid 20s (Celsius) or above it gets uncomfortably warm for me (unless I'm sitting directly under an air conditioner or something). The headphones do clamp quite hard, too. They do feel very secure on your head but I prefer a more loose feeling. It's just too much pressure for my liking, I really don't move around much when using headphones so the clamp is of little use to me (other than assisting isolation which is quite good). Overall, I find these cans less comfortable than the 225i, which certainly isn't a comfort king, itself. Another problem with the headband is that the adhesive used to hold the padding on started to come off on one side within a month . Whilst being an easy to fix issue, these are supposed to have a reputation for great quality. It feels cheaply fixed in place, and it's quick deterioration shows.
So, would I recommend these? Unfortunately not. I ended up giving them to my Dad for Christmas to plug into his guitar amp (He's much less fussy than me, and considers the $160 I paid for them to be "extremely expensive" ) after failing to sell them on eBay multiple times. They definitely deliver great bass, and respectable mids, but the treble is just too much. Maybe if you pair them with the right amp to darken them you could fix that issue. However that still leaves the build, design and comfort issues. It's a shame, because it's a pretty darn good sounding headphone for $160. It's very full sounding and pretty detailed, not to mention a pretty good all rounder if you ask me. If they fixed the comfort and brightness it would be a damn good headphone, but the flaws of the HFI-580 are too distracting for me to recommend or enjoy it fully.