I just bought a Turtle Beach X12 headset, and plugged it into my TV's audio out port (Red and white RCA connector). When I plugged the USB power into the Xbox, I could now a hear a subtle hissing sound in the background. This is when nothing is turned on. When I turn on the TV and/or the Xbox, I get good sound from the headset, but the hissing is still there. Any idea on how to fix this? Or is it just a common issue with USB powered headsets?
UPDATE: I just unplugged everything, and took the headset to my computer and plugged in ONLY the USB cable (no speaker or mic cable was connected), and got the hissing noise. So whatever this hissing noise is, it's the USB power causing it.
Best Answer
In addition to Amy B's excellent answer I would just add a few things from my experience that may help you.
Some headphones are "noise cancelling". The "cancellation" is actually caused by sound emitted from the headphones that is intended to destructively interfere with sound outside the headphones. Generally this sounds is design for you not to hear, but sometimes you can hear it when it is quiet. I don't think Turtle Beach headphones provide this feature, but I'm not familiar with your particular model.
Audio grounds are tricky like Amy B points out, but you might be able to get improved results by getting all connections to a common ground. This would be possible by:
a. Connecting the USB power cable to your TV, if your TV is digital and has a port.
b. Routing audio to your PC, and connecting USB power to your PC. Your PC will need Red/White audio ports (typically on a PCI adapter card), or you can get a Y dongle that converts the Red/White audio to the single PC stereo jack. In this case you would want to make sure you connect it to an input port (mic, line in). This may sound complicated, but it is the set up I personally use and once you figure out inputs and outputs its pretty straightforward. It also has the advantage of letting you listen to PC and Console sounds from one pair of headphones.
c. As a somewhat longer shot, you could kludge a ground cable connection between your XBox rear panel, and your TV rear panel. You should be able to just touch the wire between the two panels and listen. If the hiss goes away, you can make a more permanent connection.