Thanks for the suggestions. I will do a bit of research regarding the noise filter.
Dedicated Lines - Problem
I recently installed 2 dedicated lines (I thought!) but have noticed a loud pop through my speakers when the air conditioner and de-humidifier automatically switch on and off. My panel is made up of double breakers, each breaker controlling 2 lines. The air conditioner and the de-humidifier do not share a breaker with the stereo lines. Any suggestions what is causing the popping noise ... obviously, the 2 stereo lines are NOT dedicated.