As an update I replaced my Coax cable with a TosLink. I completely rewired back in the ICBM and the popping sound is 95% gone. If I put my ear up to the speaker I can hear it but that's it. The ICBM is somehow stopping the popping sound from getting through to the amps.

I didn't care much for 5.1 sound through the 7.1 set up so I am back to 5.1. I am still using all 4 surrounds and both amps, I ran a "Y" splitter off the L / R surround outputs from the 950 to the surround amps.

Next up, I will retire my 2 year old dvd player and maybe a new one will completely do away with the popping sound.