Per your suggestion, I checked and rechecked all my crimps and connections and even switched around the + and - connections a whole bunch, all of which made no difference. However, with more careful observation with the door closed (less background noise from the heater and other things) and moving the tweeter around further away from my head (not 3 inches from my face), I don't think its defective after all. When I tried it with normal bal/fade adjustments, there was a lot less hissing and its not audible when its further from my head, even though the engine wasn't running. Of course, when I am actually driving, it will be completely drowned out by the glorious Zetec buzzing.
Thanks for the recheck suggestion.
