Sound Volume Question

It's been like this for a while, but does anyone know what setting, or registry entry, controls Windows making the "ding" sound when changing the volume slider in the taskbar? Normally, it will make a sound representing the volume you are changing to. On my desktop, sound works fine except somehow, that volume sound is gone.

I usually right-click the speaker icon in the Notification area to get to where Sound settings changes can be made and test if they work.