Do you mean "Drop out" as, skips in the music, it stops altogether, or, the volume gets lower?
Volume reduction is an OS function to "protect hearing" and is accompanied by a pop up telling you so.
If the music is skipping, or stopping, try a fresh reboot or shutting down some background tasks.
Or are you trying to use BT? That has another whole set of issues. Along with a reboot, try repositioning the equipment.
The music stopped playing on my HTC M9 today??? Happens once in a while, PITA! I just restarted it.