I know I have told the man these things...they seem to do professional installs do not know why this problem was occurring that is why I thought it was an amp issue....during audition of it.....
the wiring I use I tell the guy to make sure it is good and check it myself.......
where he might have gone wrong is as you say overlapping the rca and the power wires I think he is majorly wrong there.....
The noise suppressor does it reduce the output and volume of the system in the car as I think I might face the same issues......
I will be going there soon in an hour or so so if possible bhai please respond.........