I spend a great deal of time reviewing various Android apps; especially those apps that have a practical purpose such as this one. It is called “Vollynx” and its’ main purpose is to help you manage and control the various volume controls and modes on your smartphone. If you give this app a try, make sure you install the widget which will give you quick access to maintain total control over the volume setting and mode settings. A key feature is you can lock in the volume settings. Vollynx is totally free (no ads or other purchase options). Vollynx can be downloaded on your phone from the Google Play Store.
Source: Google Play Store – Vollynx