Wireless headphones have been around for a while, but it's only been in the past few years that quality has gotten high enough for discerning listeners to consider using them. Many manufacturers, for instance, have turned to infrared (IR) technology for wireless signal transmission, which generally offers better sound quality and hiss-free performance than radio frequency (RF) alternatives. Indeed, Turtle Beach opted to use this IR technology for its Ear Force X4 wireless gaming headphones. While the Ear Force X4s are designed with the Xbox 360 in mind--they include a removable microphone and connections for chatting on Xbox Live--the headphones will actually deliver convincing surround sound from nearly any home theater source, thanks to their built-in 5.1-channel Dolby Digital processing.
The Ear Force X4 includes two main components: the wireless headphones themselves and a base station that houses most of the necessary jacks. The base gives you the option of either using a digital audio connection or an analog signal via a set of stereo RCA cables (red/white). That means the Ear Force X4 will work with pretty much any audio source--anything with an optical digital output (such as a DVD player or the Apple TV) or standard analog line outs (pretty much everything).
The system boasts both Dolby Digital and Dolby Pro Logic II processing; the former handles the bit stream surround soundtracks on DVD movies and Xbox games, while the latter does a decent job of creating a faux-surround effect from any stereo source. The X4 transmitter base also has a line-in volume control allowing you to just adjust the level of the incoming source. Finally, the base also features a "bypass" button that will allow you to hear unprocessed audio.
Setting up the Ear Force X4s is fairly simple. For Dolby Digital processing, you'll use the included 7-foot optical cable to connect your Xbox 360 (or another digital source) to the X4's "digital in" port on the transmitter base. If you're also using an AV receiver and surround speakers, don't worry; the X4 has a digital out port for passing the signal on, so you don't have to constantly unplug and plug in wires whenever you want to play using the headphones.
When you power on the base and headphones, make sure you place the transmitter so that it points in the general direction of where you plan on playing. Because IR signal relies on line of sight, you may notice some static if you move around the room. In our testing, we were a bit concerned with the seemingly limited radius of clarity, but since you don't move a lot when you play games, you shouldn't be affected.
In terms of comfort and design, the Ear Force X4 headphones are a bit heavy on the head. While the ear cups and headband are cushioned and comfortable, they may feel a bit weighty over an extended period of playing time. On the left ear cup is where you'll find the controls and ports, including a volume adjuster, power button, bass boost, and the port for the chat adapter that hooks into your Xbox 360 controller. The left ear cup is also home to the flexible microphone boom. We really liked that the boom is detachable, as it can become distracting when not in use. The right ear cup is where you'll install the two AAA batteries. Turtle Beach includes a pair in the packaging and claims they should work for at least 20 hours, but we do recommend getting some rechargeable ones.
In terms of sound quality, we were impressed with the overall channel separation, considering the headphones house drivers in each cup that are a mere 50mm in diameter. During our trial with BioShock, we could easily tell when an enemy was behind us. The leaky underwater city allowed for dripping and splashing to be heard all around, and the headphones did a great job of maintaining that surround-sound effect. Our only complaint with the headphones is that they don't really allow for complete noise reduction or isolation. If there is other sound playing in the same room, you may notice it more than you'd like.