Pretty much in the title... on every device I've dealt with, it is default to mute the device audio and only play audio through the headphones when you plug them in. The S4 doesn't do that? I have looked for settings to control this but can't find any. Killing the phone volume after I plug in headphones kills the volume across the board, headphones too.
How could it be thought this is a good idea for a default setting?
How could it be thought this is a good idea for a default setting?