A free program for Android, by lovekara.

If you are encountering a problem like a low volume level on your phone or like if you seemed to have maxed out your volume but you still can’t hear the audio clearly, then you should consider downloading this application called Volume Booster. Volume Booster allows you to organize and create various volume configurations based on your liking. Moreover, this is an exciting application to use because this has awesome features for you to explore and discover like its smooth interface making it user friendly, cool and functional touch controls that makes it more seamless for you to use in the long run.