The bit rate could be lower on the Fibe receiver. Bell limits most of their HDTV content to 720p so it wouldn't be good in their opinion if Netflix looked a lot better. Lowering the bit rate not only degrades video, it also degrades the audio. I wouldn't at all be surprised if Bell was limiting the bit rate for Netflix and the video and audio quality along with it. Some equipment will create pops when it switches in and out of DD or between DD formats. That could be what is happening here.