2 comments: 1 serious, 1 in search of humor.
1. Has it recently rained a LOT in your area? If so, is the hum going away as the ground dries out. If so, it's a telco problem, but they will NEVER, EVER fix it!
2. It hums because "It doesn't know the words!" (Rim shot, PLEASE) smile John C.

When I was young, I was Liberal. As I aged and wised up, I became Conservative. Now that I'm old, I have settled on Curmudgeon.