Hey JR51, I was going back through all the suggestions and I realized by the range of answers that we really are unsure what we're actually dealing with.
Can you take a brief moment to answer a few questions that might help us make better suggestions? The more information you can give us, the better we can help. It's okay if you don't have an answer, just say so and we'll either move on from that point or if it is really important we'll try to suggest an easy way to get the information.
What's the year make and model? I actually dislike automatically asking this, but a system built in 1985 will possibly have different issues than something built in 2015 and someone might have the same and already fixed this?
Is is a class A, class B, class C or something else?
Does the RV have solar?
If solar do you know what type of solar controller?If you disconnect the solar does the noise stop?
Is there an inverter?
If you disconnect the inverter does the noise stop?
When do you hear this noise? All the time, only when hooked up, only when running on batteries,only when the engine is running etc
Which speakers are we talking about, dash speakers, or speakers in the living area or both?
Is there more than one entertainment system in the coach? If yes do they both exhibit the same symptoms?
If multiple systems, do they share the same speakers?
Are there any speakers that do not make noise? If yes where are they, what are they for in the coach?
You said you have a knife switch to protect the starter battery from draining in storage. If you open the knife switch does the noise stop?
If you turn off the house main circuit breaker does the noise stop?
Yes it's a lot of questions, but the more information we can get the better we can help.
