OK..I have had it with the ground loop ignition whine on my Miata install! The installer had put a noise supressor between the HU and my amp, but the supressor has two brown wires coming out of it that are not connected to anything!!!! Looking at Crutchfield it seems that they are ground wires. My question is: Do I ground them to the main grounding point for the system in the trunk of the car? Do I combine the two wires then run one jumper wire to the ground? Is the reason why the whine did not go away in the first place due to the fact that these ground leads were never in fact grounded?

Also, the installer used one grounding point in the floor of the trunk. The ground for the amp and the HU are joined in one crimped connector then are attached with a screw and star washer. However, the connector is a small spade connector and could it be that it is not making that much contact with the chasis that I am not getting a good enough ground connection to reduce my whine?

Thanks for all who read this and care to advise!!

Ed