All of my system audio plays from my PC, for instance a Youtube video, or the ringing tones when adjusting the volume fader in the system tray. However, when I open Lync, or Skype, I can no longer hear the user audio from the far-sight.  It is there, but very faint in the background, while all other audio plays from the PC without issue. 

In your Lync client, if you go to Tools->Options->Audio Device, there should be a slider that will adjust the levels of the playback device within Lync for you, they may be set to a low level.

Hi,

Did you solve the issue with the help of Anthony Caragol provided above?

If the issue persists, please make sure audio driver update to the latest version. If not, update it and then test again.

Best Regards