Suppose you use different apps that output sound. I use audacious, Firefox (Youtube) and mplayer on a regular basis. All these have their own volumes adjusted

Suppose you use different apps that output sound. I use audacious, Firefox (Youtube) and mplayer on a regular basis. All these have their own volumes adjusted at different levels. Having a single volume isn't good enough. One app would be too loud and another too quiet. Plus I'm used to being able to change the volume on one app without affecting the others. Not having this control would be annoying.