Hi,\n\nI have a strange problem in my setup and I haven't been able to isolate the troublemaker.\nHistory: I have a set of active main speakers (B&O Beolab 9) that are fed a signal from my Marantz SR5014 AVR. I connected these on the pre-out of the AVR. I had an older Bose center and surround speaker set from my parents which I hooked up to the AVR. I changed my living room layout and had the surround speakers put further back in the room. I was using a thick speaker cable of almost 25m for the SR speaker, about 15m for the SL speaker in a 5.0 setup. All was well with this setup.\nEverything was powered off for a while since the redecorating team plastered my walls and hid that cable inside. (I could make it a little shorter now, not having it to go up and down to reach speakers. I'm pretty sure the cables themselves were not damaged during this proces.\nI added a set of speakers in the middle of the room and now have a 7.0 setup. So the 'middle' speakers are assigned to the SL\/SR channels, the previous surround speakers are now SBL\/SBR.\n\nEver since, the speakers in the back have a loud pop when powering up the Marantz. It goes in 3 stages, first a click, 4 sec later another click, and again 4 sec later a final click. With this final click, my rear speakers pop. However, this only happens it the system was powered down for several hours. Even more so, the pop is louder if the system was powered down longer: really noticeable after a couple of hours, really loud after a whole day. If I power up after just a few minutes of down time, everything remains perfectly silent.\n\nI wonder what could cause this behaviour? Any ideas on this? (For what I've read in other threads, pops and crackles occur randomly, which is not the case here.)\n\nNow I tried swapping the SB channels with the SBL channels, so having the popping speakers connected to the AVR outputs where they previously did not have a pop, and they also pop there now.\nAlso, if I disconnect the newly added speakers and only keep the 5.0 setup as before (connected to the SL\/SR channels), the speakers also pop.\nThis is strange because the only change in this setup with my old-old setup was the speaker cable which has been plastered into my walls.\nMoreover, if I disconnect only one speaker, the other will still pop. It would be highly unlikely that both cables would be damaged in the process. I was here when it happened, and I'm fairly confident that the cables are still intact.\n\nI also tried connecting the middle speakers to the 'bad'(?) cables and these remain absolutely silent even after a whole day of downtime. I wonder, if the cables are bad, shouldn't all speakers then pop using those cables?\n\nIt seems that the combination of those speakers and those cables cause a problem? But this is a weird conclusion in my mind.\n\nDo any of you have any suggestions?\nThanks a lot!