Can't use audio controls

When I plug my phone into my computer speakers I cannot control the sound volume with the volume up and down buttons.

Why is that? Has anyone else experienced this?

When I unplug the speakers I am able to control the sound again but I would really like to control the sound when it is plugged into my speakers.

Thanks

Posted via CB10

So you are physically connected with an aux cable from the headphone jack? While the music is playing, tap the More... icon at the lower right. Then chose Audio and make sure that the correct devices are selected for playing.