Ethernet connection

[Markmad]

Hi, weird question, could be coincidence? 

Recently new with sky broadband, I have already got sky q box,  samsung tv and Bose soundbar (soundbar connected to tv via optic).

Router connected to Q box via WiFi, but.... when I try connecting sky router to Q box with ethernet cable, the volume from the speaker intermittently becomes muffled (and the mini boxes I have don't seem to want to 'connect' to the Q box). If I remove the ethernet cable the problems seem to go away.  

Easier just to forget about trying to connect with ethernet cable? I have no idea how this would effect the speaker?