Hi Fans, I've a Pioneer VSX-AX5Ai which has 2 sets of speakers connected: 1. Elac 5.1 (as speaker A) 2. Celestion 2-channel (as speaker B) Everytime I switch on my amp. with speaker A as default or when I switch from speaker B to A, there will be a "pop" sound coming out from the Elac (no pop sound if I switch on with speaker B). It's quite annoying and also my worry is, in one day I will find either or both, the amp. and the speakers are burnt out. What I know is that these 2 speaker sets have difference in impedence, Elac is 6 ohm and Celestion is 8 ohm. I don't know what's happening Can anyone help? Thanks in advance.