Ear Trumpet is a small notification icon that provides app-specific volume control to Windows 10 apps.

Ear Trumpet is an open-source project, meaning the source code is available for others to use and improve upon or even just inspect. You can find updates and the source code at https://github.com/File-New-Project/EarTrumpet/releases, or just download and use it.
Windows 10 desktop showing the Ear Trumpet popup menu in the taskbar notification area.
The Ear Trumpet icon fits in nicely with the Windows style.
This utility runs in the background and provides a consolidated view of all apps using the sound system. Some apps, such as Groove Music and Videos app, have their own volume controls while others like Xbox do not.  Ear Trumpet fills this gap, and is a more convenient, consistent menu even when the apps you’re using do have their own controls.
 
This app is a favorite for sure, try it out and let me know what you think in the comments below.