I just installed an aftermarket line output converter, amplifier and new speakers in the front and back of my 2019 Insight EX. When the engine kicks in on low RPM there is an incredibly loud low frequency noise that CRANKS through the speakers. It goes away when the engine kicks off or the RPMs increase. I have separated the power and ground wires from the speaker signals, I have separated the grounds, bought a ground loop isolator on the RCA’s all to no avail. Any help would be appreciated.