I have a HP Envy 14 TS. Had the same audio problems. In my case the problem appeared when the notebook was connected to the AC adapter. In battery mode the problem was gone. I tried reinstalling audio and network drivers but no good.
I reinstalled windows 8, erasing the files option. The problem persisted when connected to the AC. Then I disabled the windows update options and only updated the driver/software updates from the HP support assitance.
So far the problem is gone. I still have to make the windows updates and see if any of those triggers the problem.