Review: Blue Microphones Mo-Fi

Headphones with active electronics for work and play
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Headphones with active electronics for work and play

Blue Mo-Fi headphones include active circuitry to provide a consistent listening experience, no matter what playback device you’re using. YOU’VE GOT active monitors in your studio; are you ready for active headphones? Blue thinks so, and they’ve just released the Mo-Fi to prove it.

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Although the Mo-Fi can be used in Passive mode just like any standard pair of headphones, they contain a specially designed amplification system to get the best performance from their 50mm dynamic drivers. (At nearly 2" in diameter, these are larger transducers than you will find in your average studio headphones.)

There are two powered modes: The On setting provides approximately 12 dB of amplification, while On+ adds low-end emphasis. It’s all done with analog circuitry; no DSP is used.

The overall design is equally unusual. Inspired by the suspension system on a Formula One racecar, the headband uses a four-bar linkage and hinged arms to ensure proper placement of the ear-shaped cups. A flat knob at the top of the headband sets the tension to fit the Mo-Fi comfortably around your head.

Weighing just over a pound on its own, the Mo-Fi includes a removable 10' cable with a 3.5mm plug at the end, as well as 1/4" and 2-prong adapters (the last for use on airplanes). Other accessories include a 4' iDevice cable with the requisite controls, a USB cable and AC adapter for charging the internal battery, and a pouch to carry everything.

The internal battery provides up to 14 hours of active power and takes 3 to 4 hours to fully charge. To keep you from inadvertently draining the battery, the Mo-Fi powers down when you remove the headphones (and the ear-cups are less than 1-1/2" apart). A light on each ear-cup indicates when you’re in Active mode.

Passive vs. Active According to Blue, amplification was added in order to provide a consistently high-quality listening experience, particularly when using laptops and mobile devices that might not have powerful enough headphone outputs for such high-performance drivers as those in the Mo-Fi. However, I found that the Mo-Fi had more than adequate output level in its Passive mode, even when used with my ancient iPhone 4s: In a crowded café with my iPhone’s output level at about 50 percent, I was able to hear my music tracks very clearly.

In fact, the Mo-Fi’s passive output—among the hottest of the various headphones I have in my studio—sounds good on its own. It has a remarkably balanced frequency response (though a bit on the darker side than my other headphones) and is surprisingly punchy. When streaming music on my phone and laptop from various services, it was easy to tell the difference between the audio quality of each station—just what you want from reference headphones.

In Active mode, playback was equally solid and punchy, with a round midrange-oriented sound that was neither brittle nor harsh. Make sure your device’s playback level is low before turning these on, because the powered output is significantly louder. The On switch is right above the cable input on the left ear-cup.

Switching into On+ added noticeably more low end, but without overdoing it. This setting sounded best with material that was mixed well and not overly compressed.

Although I wouldn’t use the Active settings for editing or mixing, they can be very handy for tracking: Drummers know how tough it is to get a hot enough headphone level that will allow them to play at full volume while being able to hear a click or guide track.

However, there is a bit of sound leakage near the area of the logo. Consequently, they may not work for tracking and overdubbing in quieter situations where mics could pick up the sound.

Overall, I feel the active features are geared more towards general listening than studio work, where output levels are strong enough to drive passive headphones. But in situations where you need high-quality reference headphones for use with consumer-based playback devices, the Mo-Fi’s Active modes provide power and fidelity without distortion or hype in the extreme frequencies.


STRENGTHS: Powerful active output. Low-end emphasis. Comfortable fit. Automatically turns off when not in use.

LIMITATIONS: Not fully collapsible. Heavier that standard headphones. Pricey.

$349.99 street