Bad ground? Speakers Popping

[EarmarkMarine]

The trim function on an I/O and the wake plate function on a towboat are known to create a wicked transient through the audio system. The pump motor of either pull a lot of current. The pump motors are triggered by either a relay controlled by a switch or directly by a switch. And it is the arc across the switch or relay contacts that cause the voltage spike. To fix this you place a capacitor on both the 'up' and 'down' triggers. In some really bad instances the parts/circuit need to be more complex. And in some cases the contacts are worn enough that you have to replace the switch.
A ground loop can make your audio system more vulnerable to this noise. But if it were just a ground loop you would probably be picking up other noises as well such as the blower motor or alternator.
Odin with Earmark has the parts to fix any noise scenario including this one which come with very complete instructions.

David

[Jughead]

I stopped by Radio Shack and picked up a couple of caps to give it a go this evening. Tanks for all the input