I've been having this issue for a few weeks and am absolutely dumbfounded as to what could be causing it. I've been troubleshooting it, made numerous changes to software and hardware, but absoluely nothing fixes it.
What makes this so puzzling is that the problems this issue causes are totally inconsistent. Sometimes, the Rift starts blacking out randomly, maybe only for a few seconds, maybe completely until I replug the USB cable (it either only blacks out or it blacks out and shows TV static, sometimes I can see flashing lights at the top of the headset). Sometimes, the audio crackles constantly. Sometimes, it's both.
Some days, the headset works completely fine. Other days, it may work fine for half an hour and then the issues occur. Other days, the issues start right away. Some days the issues are more frequent and more severe, other days they only occur once in a while.
I'm clueless and need help. I wish I could tell you everything I've tried but like I said, it's been going on for weeks and I haven't noted all the combinations of things I did to try and solve it.
Mobo: Asus B85M-E
CPU: Intel i5 4690-K
GPU: GTX 980 Ti
OS: Windows 10
Rift Sensors and Headset connected via USB 3.0 extension cords and an HDMI extension cord. The issue persists whether I use the extension cords for the headset or not, or whether I plug it into a USB 2.0 port or a USB 3.0 port.