Design and Features
The Ear Force X4 wireless headphones come with the headset, transmitter, power cable, two AAA batteries, cable to connect the headphones to the Xbox 360 controller, and a digital optical audio cable. The transmitter includes digital optical audio inputs (from your Xbox 360) and outputs (to also connect to stereo, TV, etc.) as well as red and white stereo inputs. It doesnt come with stereo cables, so if you want to use them youll have to sort those connections out on your own. A very nice feature is that you can use the digital optical input and stereo input to use sound from two separate sources. I have my Xbox 360 and PC both hooked up to the headphones, for example.The headphones use a similar design to the X3s where they are spring loaded and kind of pinch your head. The X4s are a little heavier than the X3s, but dont squeeze your head nearly as hard and are more comfortable overall. Im not crazy about the fabric covered ear cups on the X4s compared to the vinyl on previous models as they make your ears hotter and the fabric absorbs sweat. Yuck. It also seems like the battery life is a fair bit shorter with the X4s compared to previous models. I have used the X2s for months at a time, but the X4s gobbled up a new set of batteries in about 10 days. Rechargeable batteries are highly recommended. One nice feature is that you can remove the microphone if you find it getting in your way.
The transmitter has seemingly taken a step backwards to being large and bulky compared to the X3, but once you find somewhere to put it youll never think about it again.
Performance

I also want to discuss a couple of specific issues people had with the X3s that were fixed for the X4s. First off, the always-on microphone is no more. This was a problem because of the microphone monitoring feature that lets you hear yourself speak, but since it was always on you picked up your air conditioner or other noises when you didnt exactly want to. Secondly, the hiss is also gone. The X3s, whether because of the open mic or not, always had a hiss in the background. You only really noticed it during quiet scenes in movies or games, but it was kind of annoying until you got used to it. Well, I can happily say that the X4s do not have that problem. The only time I heard any hiss was when the batteries were nearly dead.
Using HDMI and Digital Optical Audio Together
I saw in another review where the writer complained you cant use HDMI and digital optical audio at the same time with the Xbox 360. This is not true, it just takes a little extra leg work. Normally, you cant use HDMI and the other A/V cable at the same time because they physically wont fit in the system at the same time. There are two ways to get around this. 1. Buy an official Xbox 360 HDMI cable ($50 alone or included with Elite system) that comes with a special audio cable that has a slimmer profile so you can plug them both in at once. Or, 2. Modify the exising A/V cable so it fits by removing the plastic casing on the end that connects to the system. It takes a bit of digging into the plastic at the seam before youll be able to get a flathead screwdriver in there to pry the plastic pieces apart, but once you do the plastic pops off and you can now plug it into the system at the same time as an HDMI cable. Not exactly Microsoft approved, of course, but it is a very cheap and very effective way of getting the job done. Check out this article for more information on this mod.Bottom Line

My recommendation comes down to this. If you are looking for your first set of wireless headphones, the X4s are a pretty solid choice. If you already have a set of X2 or X3 headphones, Im not sure that the X4s offer enough of an improvement to warrant the $200 price if you are looking to upgrade.
One final feature I want to touch on is that the transmitters for the X2, X3, and X4s are all compatible with all of the headphones. So if you have more than one pair, multiple people can use them from the same source. Or you can have one set of headphones you use in multiple rooms. Kind of a neat, unexpected feature that is useful enough that, despite what I said above, make the X4s worth considering even if you already have previous models if you intend to use them this way.





