Anyone have new info or clues on this since last posting in December?

My car just developed this. I turn on ignition, all is good. At exact moment car revs down to 700 RPM, right door speaker starts hissing, white noise at about 1KHz range. If you put your ear up to the other speakers you can hear it much softer, it's worst in the right door.

This occurs with radio OFF. But you can hear it when radio or CD player is on, too.

What would push power thru a turned-off amp? Noise seems to increase as speed goes up (just like radio does when on).

I assume amp is not always on because it takes a few seconds to get sound when I turn the stereo on.

Radio was swapped out in March because of LED issue.