Design and features:Although this home/studio-style over-ear model lacks active noise reduction, the closed design helps to reduce both outside noise and sound leaking out into your environment. The headphones have very high sensitivity in active (battery-powered) mode, so they can easily provide satisfying volume levels when used even with lower-powered portable audio devices. But the amplification produces high levels of background hiss and/or hum when used with home audio and studio equipment. When in passive (non-battery) mode the headphones have medium-high sensitivity, so they're able to provide satisfying volume levels even with lower-powered portable audio devices. The built-in rechargeable battery-powered amplifier has a bass-boost option, and automatically turns on when the earcups are separated; it shuts off when earcups are returned to a rest position. This model has a headband clamping pressure adjustment and comes with a 119-inch detachable standard audio cable, a 47-inch detachable audio cable with built-in mic and answer/player control button for iPhone/iPod/iPad and smartphone use, a mini-plug-to-1/4-inch-plug adapter, a mini-plug-to-airplane-jack adapter, a USB charging cable, an AC adapter, and a carrying pouch.
Sound quality: The MoFi delivers very good overall sound, with a warm character. There is no significant difference in sound quality between the unpowered ("Off") and powered ("On") modes, though the powered mode plays much louder, especially when used with home/studio electronics. Bass has good impact, with decent definition, and goes deep. Midrange is a bit muted and hazy, and treble is somewhat recessed. The overall sound is a bit closed-in, with decent dynamics. Using the "On+" (bass boost) powered setting provides a mild bass boost that probably would not be offensive to critical listeners. The amplified settings are usable with mobile devices, but not with home audio or studio equipment that uses AC power, as the amp produces high levels off hiss and/or hum that can be heard even when music is playing. This wasn't an issue when the headphone amplifier was turned off.
Comfort: We found that these headphones produce a moderate to moderately high sense of pressure around the ears, depending on how the headband is adjusted. (Users with larger heads might experience more pressure at the various settings.) The earpads may feel hot and/or sticky after prolonged use. The MoFi is fairly heavy in general, and some users may find them noticeably top-heavy. The powered mode plays much louder than unpowered mode, especially when used with home/studio electronics; care should be taken to make sure that the volume level on the equipment it is connected to is turned way down, or that the headphones are not worn while the switching from the unpowered to the powered mode.
