Michaelbezanis

Just a quick overview of my build... 0gauge ofc from + battery terminal to inline fuse, 0g in 0g out, through firewall down driver side alone to back trunk. Then 0g in a fused power/distribution block split to 0g power to a skar audio 2000rms mono amp and a 4g power to a skar audio 1000rms 4 channel amp. Power and grounds from amp to the block also and then the block is grounded with 0g to the frame. (2) skar ddx 12s are powered by the monoblock and (4) 6.5 deaf bonce sylvesters are powered by the 4 channel. Both amps are mounted on the back of rear seats with the sub enclosure behind in trunk. I did not strap the box down like an idiot and one of the sub wires was pinched between the box and amp. A loud rapid popping followed immediately by a horrible interference sound places through all speakers. I believed the wire was exposed and made contact with amp chassis. I tested the signal after with oscilloscope and the signal was terrible. I ordered a new amp and replaced it still to have the same sound. The entire system powers on as normal, no protect mode. All fuses changed. Power and ground cables changed. What is creating this sound? It is only when RCAs are connected to amp. It plays with the sound at 0 through speakers when the headunit source is on. It plays with engine on and off. Both RCAs and speaker outputs were tested with scope and neither are clipping or showing irregular voltage? How can I troubleshoot this? Am I forgetting something obvious?