Blue Mo-Fi Headphones

High-resolution headphones with built-in amplifier

Headphones are one of those things that every engineer and musician needs - even when on the go. Although I still primarily mix on speakers, checking mixes on good headphones has become more important since more listeners are using headsets as their primary listening devices. We've all become more mobile, and writing and recording on on the go with laptops and other mobile devices is now commonplace, but there are some challenges. First is expense - good headphones that are accurate enough for production purposes are generally not cheap. Another issue that arises when using headphones is their relative inaccuracy compared to speakers; it can be difficult to get an accurate picture of the tonal balance when listening on inexpensive headphones, just as it can be when using inexpensive speakers in a poorly treated room. 

Another big issue with headphones is the fact that most mobile devices lack sufficient power to properly drive professional grade headphones to decent monitoring levels, and sometimes you wind up with more distortion in the signal than you'd prefer because you have to turn up the playback device to its limits. 

Blue is well known for their transducer expertise and distinctive sense of style, although in the past they've focused on microphones. Now they've made their first foray into the world of headphones, and it's a doozy. What makes Mo-Fi (now known as Mix-Fi*) so special and unique? 

What You Need To Know

• Mo-Fi headphones are the first product in Blue's new headphone line, with more models to come. They are a sealed back, circumaural ("around the ears" as opposed to sitting on them) design. While fairly conventional in that respect, they do offer a few surprises that make them rather unique.

• Blue's Mo-Fi headphones feature high-precision fiber-reinforced 50mm dynamic drivers with high power handling capacity. Impedance is rated at 42 ohms, and frequency response is 15Hz - 20kHz. 

• The ear cups are shaped like your ears, and provide sufficient room so that my ears sat comfortably within them. The ear and headband pads are covered in a soft premium vinyl that looks just like leather, and they are filled with memory foam. The overall fit, comfort and seal are quite nice. Depending on how hard you have the adjustable headband tension set and how loud you turn things up, isolation is more than good enough to allow you to use Mo-Fi as a pair of tracking headphones in the studio without having to worry about excessive headphone bleed or feedback. 

• Blue's Mo-Fi has an onboard 240mW audiophile grade headphone amplifier built in, so even when using them with low-output devices like laptops, tablets and phones there's plenty of juice available. They're capable of getting VERY loud - so loud in fact that you should take care to heed Blue's warning about lowering the level on your playback device before trying them out for the first time lest you unintentionally blast your ears! It's not just about being loud though - the amp allows you to run at a comfortably loud listening level while still maintaining lots of headroom and keeping distortion low. 

• The Blue Mo-Fi headphones offer three different modes of operation - "Off" for passive and unpowered use (they'll run fine in this mode, even with a dead battery), as well as "On" which engages the onboard amplifier, and "On+" which is also powered, but engages an onboard analog bass boost circuit. The three position switch is cleverly built into the headphones right next to the cable connector on the left ear cup. Switching is easy to do, even while wearing the headphones. 

• Also located nearby is a mini USB jack. This is used strictly for recharging the onboard 1020mAh battery. Even though the battery is charged at the factory before shipping, Blue recommends charging it again before first use. 

• To help make the battery last as long as possible, the headphones automatically sense when you take them off and shut the battery down when you do. It's automatic, and you don't even have to think about it. Pick them back up and put them on, and they turn right back on. 

• There is a LED on each ear cup just below the Blue logo. They flash slowly when Mo-Fi's battery is charging, illuminate continuously when the headphones are being worn, and flash rapidly when the battery charge drops below fifteen percent to let you know it's time to recharge.

• An AC to USB charger and 1 meter USB to micro USB charging cable are included. Charging is relatively fast - it takes about 3-4 hours for a full charge. Battery life is actually pretty good, and you can typically get up to 12 hours of playback time from a full charge. 

• Other accessories provided include a 1.2 meter cable with Apple iPhone / iPad controls for volume and mute for on-the-go use, a longer 3 meter cable for at-home or studio use, a 3.5mm to 1/4" TRS adapter, and a two-prong airplane adapter. Blue also throws in a nice heavy-duty soft case / bag that holds the headphones, and even includes an internal storage pocket for the cables and accessories. 

• Mo-Fi uses a rather unique multi-jointed headband design that allows for quite a bit of adjustability and customization in the fit. Inspired by race car suspensions, the headband easily adjusts to different head sizes and ear locations. A rotary control on the top of the headband even allows you to adjust the amount of tension and compression - how "tight" the cans press against your head, with higher settings resulting in a snugger fit, better seal and improved bass response. 

• An onboard amplifier is a nice addition, but only if it makes things sound good, and boy do these cans sound fantastic! In fact, I don't think I've heard anything out there that can touch them in the accuracy department in the under $500 price range. The stereo image is wide and natural sounding, and the frequency response is full and incredibly balanced and flat for headphones. The midrange is exceptionally well represented and nicely matched with the extended and sweet highs and deep, detailed bass. Noise and distortion are also both quite low (0.004% THD+N; SNR, self-noise <105dB), all of which makes Mo-Fi an exceptionally good choice for critical headphone listening. And when you're ready to have fun and do some leisure listening, boosted bass is just a click away, giving you the best of both worlds in one outstanding pair of headphones. 

Limitations

• Due to their design and the extensive use of metal in their construction they're a bit on the heavy side. The overall weight is 466 grams - 16.44 ounces. Due to the unique headband and the wide range of adjustment it provides they're reasonably comfortable, but the weight is still noticeable. 

• Because they're sealed cans, care should be used to make sure your situational awareness is up when wearing them out in public. You won't get any audible cues to potential dangers such as a car approaching so as with all sealed, circumaural headphones it's important to pay attention to what's going on around you when walking around while wearing them in public. 

• You really need to be cautious about Mo-Fi's switch position and the output level of your playback device. Failure to do so can result in extreme volume that probably isn't the safest thing for your hearing. To be fair, Blue does warn users about this in the manual and with  a warning tag on the headphone cable. 

Conclusions

Blue leads the pack with the first powered headphones, and they really are exceptional. Minor weight issues aside, I really love these cans! They are capable of getting incredibly loud but more importantly, the sound quality is first-rate. It's cool that you can tailor the bass response to your preferences. Unlike some cans that lean towards heavy bass emphasis whether you like that or not, Blue gives you a choice - you can have natural, uncolored sound in the "On" position, or fuller, deeper bass with the "On+" setting. I love the fact that the battery is onboard, charges quickly via USB, and you don't have to use disposable batteries. Even better, when the battery charge dies after 12 or more hours of use you can still use Mo-Fi passively, although at substantially reduced volume, as you'd expect. 

Blue includes all the accessories you need, and since the fit is so customizable comfort is quite good even given their weight and metal construction. While some people may think powered headphones are a gimmick, it's actually a great idea that has been very well implemented. As with active studio monitors, the performance is optimized by carefully matching the drivers and the power amp that drives them. With Mo-Fi, Blue has developed a pair of headphones that provide outstanding sound quality, even when used with less than ideal, low-output devices. With their innovative onboard amplification, user-selectable accurate or boosted bass EQ settings, solid isolation, and unique headband and custom fit, Mo-Fi will no doubt become popular not only with users of mobile devices, but also with musicians and engineers. Blue's first headphones are innovative, comfortable, and sound great - and that makes Mo-Fi a real winner!

Resources

B&H Blue Mo-Fi Powered High-Fidelity Headphones online catalog page ($349.99 "street")

Blue's product web page 

Blue Mo-Fi introduction video:

Mo-Fi headphone amp video:

Headphone drivers video:

Want to discuss headphones, recording, or anything else studio-related? Make sure you drop by the Studio Trenches forum! 

* EDITOR'S NOTE: The Blue Mo-Fi Headphones are now known as Blue Mix-Fi headphones. They're the same model - only the name has been changed. 

Phil O'Keefe is a multi-instrumentalist, recording engineer / producer and the Senior Editor of Harmony Central. He has engineered, produced and performed on countless recording sessions in a diverse range of styles, with artists such as Alien Ant Farm, Jules Day, Voodoo Glow Skulls, John McGill, Michael Knott and Alexa's Wish. He is a former featured monthly columnist for EQ magazine, and his articles and product reviews have also appeared in Keyboard, Electronic Musician and Guitar Player magazines.