I have my Tsi-500 Speakers bi-amped using an Adcom GFA-535L on the top poles and a GFA-545 on the bottom poles. Both amps are sending a signal but I can only get sound from the bottom poles. Nothing from the top. If I connect either amp to the bottom poles I get sound. If I connect either to the top poles I get no sound. I am testing this with a static white noise signal, so shouldn't I hear something from the top poles? Even if is the tweeter? Why do I only get sound from the bottom poles?