I had the same problem and it was the navigation volume. There are several volume options and I wasn't able to find a separate screen to adjust them. Next time the music pauses, crank the volume up some more and see if the Nav icon is showing in the volume bar. If it is, then you are adjusting the Nav volume and can tell where it currently is set and can continue to adjust it during the silence. I find it odd that the different volume options aren't reachable through one screen. This drove me nuts for about 3 rides before I finally figured this out.