I have the 2104 GT with nav. Sound through the CD is great, dynamic, well balanced and the door speakers are well heard. With the radio or Sirius, it sounds flat, I can't hear the bass through the door speakers and generally no better than a cheap car radio system. I can understand radio frequency over the air waves is limiting, but satellite radio I would think would sound better than radio airwaves. What is going on here. Perhaps the radio doesn't put out enough power to drive the speakers? I would think that would be the same no matter the source. Your thoughts?