Ultrasone has carved out a notable niche in the high-end headphone market since its founding in 1991. One of its latest models is the HFI-680, a full-size pair of headphones that retails for around $220. The HFI-680 is a handsome design, and its build quality is about average for a model in this price range. (For what its worth, many of the Ultrasone headphones we've tested over the years were made in Germany, but the HFI-680s are made in Taiwan.)
The central part of the HFI-680s' outer earcup is covered by machined metal; the other side that faces your ears features an oval faux-leather covered cushion. We like the oval shape because it better conforms to the ear's natural contour, which is an improvement over the round earpads featured on other Ultrasone headphones. Some people may find the faux leather makes their ears perspire in the summertime, but we didn't have any problems on that front.
The sturdy padded headband adds to the design's overall comfort. A 10-foot headphone cable is permanently attached to the left earcup; the cable is terminated with a standard 3.5mm mini-plug and there's a screw-on 6.3mm adapter. (There's also a second 6.3mm-to-3.5mm adapter, too, but why you wouldn't simply remove the first adapter instead is beyond us.) The HFI-680s can be folded for compact storage, and Ultrasone includes a soft carry bag and an Ultrasone produced demonstration disc of music.
The headphone features Ultrasone's S-Logic Natural Surround Sound Plus technology that bounces the 40mm gold-plated driver's sound off your outer ear (instead of firing directly toward your eardrum). Ultrasone claims the technology produces a less headphonelike sound, so it's a little closer to the sound of speakers. We can't say that's what it sounded like to us; the HFI-680s were more "closed in" and sounded more canned than comparably priced Sennheiser and Grado models, which use an open-back design instead.
To that point: one definite advantage of the HFI-680s' closed-back design is that it hushes outside noise. It's not as completely isolating as a bona-fide noise-canceling headphone, but it gets you halfway there. The isolation also works in the other direction, limiting how much of the headphones' sound will be heard by people around you.
The HFI-680s, like all of Ultrasone's headphones, feature what the company calls "ULE technology" (ultralow emission). The company claims that most headphone drivers produce low-frequency magnetic fields. Ultrasone employs MU Metal shielding (a nickel iron alloy), which--again, according to Ultrasone--reduces magnetic radiation by up to 98 percent compared with other headphones. It all sounds quite impressive, but we have no way of independently verifying it.
We listened to the HFI-680s over an Onkyo TX-SR805 receiver, a Schiit Audio Asgard headphone amplifier ($249), and an iPod. The Onkyo sounded more laid back and mellow compared with the Schiit Audio amp, so yes, the headphones' sound quality changes, depending on what it's plugged into. Our first impression of the HFI-680s' sound with the Onkyo receiver was, wow, these headphones make a lot of bass! Not only that, the bass is deeper than we've heard from similarly priced open-back Grado and Sennheiser headphones. The open-backed headphones may make less bass, but the bass definition of the Grado SR225i was better than the Ultrasone's. The HFI-680's treble has a sweet, refined character, so it's easy to listen to these headphones for hours on end.
The HFI-680s sounded surprisingly good on heavily compressed and harsh recordings, like the new Arcade Fire CD, "The Suburbs." That recording's flaws were hard to ignore over the Grado SR225i headphones, which seemed to highlight the most irritating aspects of the disc's sound mix. The HFI-680s' softer, less pronounced treble and bassier bottom-end took the edge off.
On good-sounding recordings, we definitely preferred the SR225i headphones because they sounded more realistic. Puente Celeste's "Nama" CD is an audiophile recording, so the voices, clarinet, accordion, acoustic guitars, bass, and percussion on this world music CD had an almost 3D presence and solidity on the Grado pair. Switching back to the HFI-680s, "Nama's" soundstage was squashed flat and the treble wasn't as clear. At this point we turned the Onkyo receiver off and started listening through the Schiit Asgard headphone amplifier, which improved the sound of both headphones, but we still preferred the Grado on better-sounding recordings, and the HFI-680 on compressed rock music.
We next auditioned the HFI-680 in our home theater as we watched the "King Kong" DVD. Kong's grunts and roars were fearsome, but we felt the HFI-680 headphones foreshortened the soundstage depth. The jungle scenes populated by buzzing insects and birds didn't sound far enough away, but when the dinosaurs stampeded, their pounding feet made the jungle ground shudder.
We're not sure how many of you would want to use such a large headphone, with its 10-foot-long cable, plugged into an iPod or Zune, but the HFI-680 sounded spectacularly good on the streets of NYC. Bass was rock solid, dynamics opened up, and the midrange clarity was well ahead of what Monster Turbine in-ear headphones ($300) can achieve. If you can handle the extra bulk, the HFI-680s won't disappoint.