At the top of the Touring forum there are stickys, including one on Harman Kardon self-diagnostics. See if that gives you any helpful information.

Carl

 

No, its a random quiet, and then normal volume, and then quiet. It doesnt seem to have anything to do with my VOX settings - happens when sitting still in my driveway with VOX set way low...

I'll search the sticky - thanks..

 

Try setting the vox higher and see what happens It's been a while since I set mine up and can't remember what my settings are. But when it's windy or am on the throttle the vox kicks in the music goes way down.

 

That it, it is normal ops