Per-application Audio Device Switcher
The Per-application Audio Device Switcher facility allows to redirect the sound output in each sound-playing application individually to different audio hardware devices (if you have more than one of them installed in your PC). Most modern video cards have embedded audio hardware to support such combined video/audio output standards as HDMI or DisplayPort.
Now you can bind available audio devices (internal/external sound cards, HDMI/DisplayPort outputs, etc.) to certain monitors, so that any multimedia application being put on a monitor will automatically redirect its audio playback to the bound audio device.
Also, you can change the audio device used by a certain multimedia application in its specific window settings - either automatically (at startup) or manually (via title button, window menu item, or special window that can be invoked via tray icon's context menu command).
Per-application Audio Device Switcher facility can be enabled/disabled here.