Windows: SpeakerAdmin allows a user to override system volume controls and create a schedule for your computer's volume.
The app gives full control to Speaker Admin for the scheduled duration, which means manual volume adjustments will not work. This can be handy if you want to manage a child's machine, or schedule some quiet time at night. You can give complete control to SpeakerAdmin for the entire day or just set it for certain blocks of time.
If you use the fantastic NirCmd app, you can accomplish the same task with scheduled volume commands (without needing to give complete control to the app). Hit the link below to check out SpeakerAdmin, and be sure to uncheck the crapware bundled in its installer (a practice we're seeing far too often lately).