If the popping comes out of the subwoofer of the right 8020 the amp built into the speaker cabinet that drives the sub could have a problem. If you get close to the side of the cabinet that the sub is on you should be able to tell if the pops are coming from there. Call DefTech tech support. The amp probably only has a one year warranty but my recollection is that they will make a replacement available at modest cost out of warranty.
If the problem is in the Pioneer it will switch speakers if you exchange the right and left speaker wires at the back of the receiver (or change the speaker physically).
If the problem only happens with one source then that could be the problem.
ok thank you for your response what I did was I disconnected my whole system and reconnected the receiver and all the speakers ,I did find one surround sound
speaker not connected completely ,and also the power cord to the receiver was not completely plugged in My guess tearing down Christmas moving things around
anyway no popping after I reconnected everything . Thank You americanaudiophile