Running Poweramp and beeing on my lock screen I cannot change the volume by the earphone´s remote. Play/pause and skip (double click) works very well. If I double click volume up or down it triggers LG´s special features (camera and notepad). Same misbehavior when using the hardware buttons on the left side of my phone. Tried different earphones.
With unlocked phone and on android's home screen the volume buttons change the ring tone's volume.
With unlocked phone and onscreen Poweramp
@jofland I can't confirm any sample rate changes (actually, such dynamic changes are not supported by device audio subsystem). This is some other sound played (e.g. beep) on that sample rate.