I have to give props to mysticalvibes, whose instrucable helped me out when I made my headset.
I had all this stuff at home already, so essentially it cost me nothing, but you can get this stuff pretty cheap of ebay or something.
What You'll Need:
-Xbox wired headset
-Pair of Headphones
-Soldering iron and solder
-Electrical tape/Heat shrink
-Phillips head screwdriver
Step 1: Disassemble the Xbox Headset
Start by taking off the foam ear cover on the headset so you can remove the speaker. The speaker easily comes off by pressing in the three (3) black tabs.
You will need to desolder the wires from the speaker so it can be completely removed.
You can now remove the heat shrink from the microphone wires and desolder them.
The boom can be removed by undoing the screw. You can also remove the cord by undoing the knot and pulling it through the rubber bit.
Step 2: Preparing the Headphones
You will need to drill 2-3 holes, the hole for boom and mic wires can be the same or separate.
You will need to find a couple of drill bits that will make holes big enough to fit the boom and cord.
With mine I decided to use the little rubber bit from the xbox headset that the cord goes through to make them look more legit, but it took me like 20mins to take it out of the xbox headset and then another 20mins to put it into my headphones, you can do it aswell if you can be bothered with the hassle.
Make sure you test fit to where you headset will be to make so it's in the right place before you drill.
Step 3: Final Touches
You can solder the headphone wires onto the speaker if you want, THE MICROPHONE WILL WORK IF THEY ARE NOT CONNECTED, and I'm not that good at soldering or electronics stuff so I didn't bother with it, and I also have it set to play voice through both headset and speakers on my xbox.
After you finish soldering you can tape/heat shrink up the wires and reassemble you headphones.
Now you should have your own custom Turtle Beach like headset.
Step 4: My Setup
Originally I was gonna buy a cheap pair of wireless headphones from ebay, but I couldn't be bothered, but thats something you could do if you want a semi-wireless headset.