Did a quick google and returned this -
http://www.turtlebeach.com/support/index.php?View=entry&EntryID=603420326
on the official TB forums - ISSUE:
Static/Popping/Crackling noises are usually the result of system resource
conflicts or excessive activity along the PCI bus. It could also result from
System overheating, failing fans or even an inadequate System Power Supply.
Often times this is caused by a Video Card, which are known to deplete
system resources in order to achieve better performance at the expense of
other applications.
EXPLANATION:
When another device illegally locks up the bus for more than 1/88200th of
a second, there's a good chance you will lose audio samples resulting in
a glitch in the recording or playback.
link says that as the causes, suggests a few fixes hope it works for ya.