OpenVR Volume Control
As of this writing, changing the volume from within VR involves pointing at a 2D volume control. I found that frustrating and difficult to do precisely, as I often wanted the volume at or near the lowest level, so this allows adjusting the volume by dragging a giant virtual slider with haptic feedback. It consists of a plugin to interface with Windows' CoreAudio, and a HapticRack and the LinearDrive example interaction from the SteamVR Unity plugin.
The audio gear on the table is from a paid asset package, and will not be included in this repository. The utility will still work if you don't have it - the gear is entirely cosmetic.
The Unity plugin I wrote to interface with system volume control is MIT licensed. Code from other sources, such as the SteamVR Unity plugin, and Steam Audio Unity plugin, are subject to their respective licenses.