When you enter a FaceTime call in OS X, as of Mavericks, it lowers the volume of everything else besides the call. There's no way to disable this "feature." People here suggested disabling audio ducking in Voiceover Utility, but that doesn't have any effect, at least not in Yosemite.
Any suggestions for a hack solution to fix this? I don't want to install some system-wide audio mixer to help, but I'll happily mess with the FaceTime application or some system settings. I'm guessing there's some library it's using to control the system volume, and I'm trying to find a way to prevent the app bundle from accessing it.