Blue Microphones is known for its wide range of quality vocal and instrument mics, from super-affordable USB models to pro-level gear with designs based on the heyday of radio. The Mo-Fi, however, is the company's first headphone pair. At $349.99, the Mo-Fi is for serious listeners—and everything from its inspired, bizarre design to its internal analog amplifier feels different and new. The audio performance is extremely powerful, and has three modes—passive, active, and an enhanced active mode that sculpts the lower frequencies a bit. This is the most involved headphone design we've seen at PC Labs, but in the end, only sound matters, and the Mo-Fi earns an Editors' Choice for its audio performance.

Design

Describing the physical design of the Mo-Fi is a daunting task: There's a lot going on here. The plush headband morphs into what looks like robotic arms, to which the heavily cushioned circumaural (over-the-ear) earcups are attached. The cups are actually shaped like ears, and they're extremely comfortable. The Mo-Fi looks heavy (and it is), but somehow, Blue managed to make this bulky, chunky, visually hypnotic design pleasant to wear for hours without discomfort.

The fit is customizable to a certain extent—a dial on the headband applies variable tension so that the earcups are as firmly against your head as you want them to be. The headphones ship with two detachable cables—one with an inline remote control and microphone, one without. A Power switch is located above the jack for the cable on the left ear—this is also where the micro USB connection for the charging cable is. (A charging cable and a wall plug adapter are included.)

The power switch is the least graceful aspect of the design—it's tiny, and so it's hard to tell what mode it's in at a glance. Even the click-stops don't feel super-precise, so you sometimes need to double-check to see if you're in On or On+ mode. More space between the modes on the switch, or just a different design altogether for this function, might have been more successful. Beyond that, the design is handsome, insanely innovative, and well-executed.

Powering the headphones is essential to get the most out of them, but they shouldn't be used while they're charging—you'll almost definitely hear some interference. Blue acknowledges this, but claims it's not a flaw—just a reality of powered headphones. The Mo-Fi is equipped with a smart feature, thankfully, that will shut down the circuitry when it hasn't played audio for awhile. This saves battery life, and it's a good thing, because the switch is so small, it's easy to forget the headphones are on. (The amber backlighting when the headphones are charging is a nice visual touch, but the lights failed to remain on when the unit was powered as they're supposed to.)

In addition to the cables mentioned, the Mo-Fi ships with an airplane jack adapter, a ¼-inch headphone jack adapter, and a black carrying pouch large enough to house this massive beast.

Performance

We are essentially reviewing at least two headphone pairs—and almost three—thanks to the passive, On, and On+ modes of the Mo-Fi. The switch powers up an internal amplifier, which is all analog. That's a rarity, and one which means one important thing for purists: There's no digital signal processing here. That said, there's plenty of boosting, cutting, and sculpting.

As is often the case, I often favored the passive mode. The headphones are not nearly as loud in passive mode, which hardly matters—in On and On+, the headphones get so incredibly loud, you could do serious damage to your ears if you aren't careful about your sound source volume levels when you switch over. Aside from not being as loud, the highs are less bright and the bass less pumped in passive mode—and the Mo-Fi's drivers in this mode sound a bit less glossy, a bit more accurate to me.

Flipping the switch to On mode—again, lower that volume first, and don't say I didn't warn you—your ears are immediately greeted by not only a boost in volume, but a sheen of treble and enhanced, rich bass. On+ is not the extra bass mode that some might expect it to be—though it does sculpt the lows and low-mids more. It's more likely to add lows to tracks that don't have a bunch of low-end to begin with (think: folk music) than it is to bring out the subwoofer potential of a dance track. But, without a doubt, that subwoofer potential is already on display to a generous degree in On mode.

With the knowledge that passive mode lacks the sheen and richness of On mode, and On+ adds bass presence to tracks that might not otherwise have much, let's focus on what could be considered the default mode for the Mo-Fi: On. In On mode, tracks that pack tremendous sub-bass presence, like The Knife's "Silent Shout," are delivered with a bass response that you can feel. Unlike most pairs that really boost the lows, however, it always sounds natural and well defined. The lows don't overtake the mix—things always remain crisp, but on electronic mixes like this one, the Mo-Fi sounds like it's packing a subwoofer, yet its presence is more nuanced than over-the-top.

On Bill Callahan's "Drover," the drums receive plenty of bass boosting, but they maintain a natural sound—which is not often the case when these drums, in particular, are boosted in the lows. Callahan's vocals have a beautiful richness to them through the Mo-Fi, mainly because the low-mid presence is matched by a perfectly crisp high-mid edge that helps them stay out in front of the mix. This is not a super-flat sound—it literally sounds like it's being amplified—but it's a very musical, dynamic sound that distributes the boosting evenly and maintains balance. Critics might say it sounds overly bright at times, which is fair, but won't be a deal breaker for most listeners. Simply put, at moderate volumes, this track sounds amazing through the Mo-Fi.

Jay-Z and Kanye West's "No Church in the Wild" actually shows some of the restraint the Mo-Fi possesses—the sub-bass synth hits on this track are not insanely boosted. Trust me, you'll have no problem hearing them, but they don't overpower as they often do on bass-heavy headphones. Here the attack of the kick drum loop gets as much attention as the vocals and the sub-bass synth—a powerful, but balanced, sound.

Classical tracks, like the opening scene in John Adams' "The Gospel According to the Other Mary," sound jaw-droppingly beautiful through the Mo-Fi. You hear the size of the room the opera was recorded in, you hear the resonance of the lower register strings, but it sounds real, not boosted and sculpted. The highs are perhaps a bit brighter than some purists will want, but this is a sound signature that maintains clarity without skimping on the lows or the highs—it sounds fantastic.

It's safe to say I've never tested a headphone pair like the Mo-Fi, and at times, I loved it. At others, it seemed like a pair trying to do too much—I'm less a fan of the arguably superfluous On+ mode, for instance. I wouldn't recommend the Mo-Fi for studio tracking, partially because the powered mode doesn't really offer a flat response, but mainly because there are also plenty of far more affordable options to monitor your mix with. Blue Microphones has made a high-end consumer headphone pair with all sorts of tweaks and features.

Are the three listening modes and internal amplifier overkill? Not for those who want to be able to have more control over the audio output of mobile devices like the iPhone, which aren't exactly made with audiophiles in mind. The massive design is heavy but exceedingly comfortable, and the audio output is more powerful than any pair we've tested. The sound signature may be sculpted in the powered modes, but that doesn't mean the Mo-Fi doesn't sound excellent.

If you're shopping in this price range but prefer a passive, less involved headphone pair, both the Sennheiser HD6 Mix and the V-Moda Crossfade M-100 are excellent options. If you wish to spend less, consider the Sennheiser HD 558 and the Griffin WoodTones Over-the-Ear Headphones—both of which offer powerful, enjoyable audio performances in varying price ranges. The Blue Microphones Mo-Fi is not a flawless headphone pair, but the sheer creativity of its gracefully executed, complex design nets it our Editors' Choice Award.