I did a search and all I could find is this thread:
https://my350z.com/forum/showthread....ghlight=static

I'm having the exact same problem and can't figure out what is wrong. It's driving me nuts though.

I'm getting a hissing/buzzing/static noise that sounds like it's coming from the rear speakers or behind it. Sometimes its off and on and sometimes its on constantly. It's loud enough to hear clearly. It makes the sound even when the radio is off.

I have no aftermarket sound system or anything. The funny thing is a used Z I test drove last year had this problem to and I didn't buy it because it made me a little unsure about it. Is anyone else having this problem? Any solutions?

Thanks.

 

I have something quite similar to what you're describing, and for me it's the fuel pump.

 

So it'll always be there? Nothing I can do about it? It's weird because I didnt hear before, I just started getting it about a week ago...

 

Check the license plate and frame. Mine buzzed occasionally. Put some double stick tape behind and it's good now.

 

I have the same static noise. It sounds like a bad phone connection echoing through the car.

I just wrote it off as one of the million Z problems/ issues/ whatever you want to call them.

 

It could be (although I would think it wouldn't sound like static) a lose panel or the passenger side seatbelt. I've heard rattling and buzzing sometimes from things like that.