Trying to sort this out in my coffee deprived state...
You have two chargers and one wall wart? With several batteries, with either charger, and the same wall wart, you get the sound?
If that's the case, then it points to a bad wall wart, not a bad charger.
Have you tried any other source, e.g. a USB port on your computer? If so, do you get the sound? Again, if no sound in that setup, it points back to the wall wart.
Good luck!