Audio Systems: popping, white noise in speakers when accelerating and radio off., honda odyssey, factory radio

Question
how can i get rid of the popping and white noise when accelerating and radio off?
2000 honda odyssey. factory radio, after market amp and speakers.  

Answer
That's an interesting set-up... factory radio with pre-amp out to the amplifier, or did you use a speaker-to-line-level converter?

My first thought would be alternator noise or an intermitttent connection to ground.  Can you tell me how your amp is connected to power and how you grounded it?