Speaker whine, correlate to engine RPM. Where do I find all ground connections?
 

Hi guys, besides my LPG/Gasoline fuel trim issues, I have another one that I have since I bought the car roughly 1,5 years ago, and it's slowly getting on my nerves.

The speakers always give off this whine, one day it's less, another day it's really annoying. I read that this is because of bad ground connection, and my question is where all the ground connections exactly are. Where do I need to look? It also tends to be a specific speaker in the left door (tweeter), and in the middle on the dashboard. I haven't tried the other ones. People comment it sounds like a turbo, you get the idea...

So, where do I found all the ground connections, so I can check and clean them? What else should I look out for?

Its all in the fsm

And get a new noise filter, mazda calls it"condenser", its located around the coil area.

What's an FSM? And where do I locate the noise filter?
What coil area are you talking about?

FSM = Factory Service Manual.
You can find it here: Foxed.ca - Mazda RX-7 Manuals

I already had the FSM before, and found the exact wiring page of the speakers and amplifiers. But I still don't see where I should find all the ground points that are connected to the chassis. What should I look for?
EDIT: I see it, g as in "Ground" I guess... I was looking for this symbol all the time: http://incompliancemag.com/wp-conten...rMark_5019.png

Do you have an after market Stereo or amp?

If yes check there first.

What about speakers? Are they stock? If no check there.

Speakers are stock. No aftermarket stereo or amp whatsoever.