Audio Systems: car stereo problem, noise eliminator, pioneer supertuner

Question
I have a 1994 Nissan PU. Best Buy put in an aftermarket stereo system ( I put in the speakers and two amps). One amp I hooked up to the front speakers and the second one was for the sub-woofer box. When the amp to the front speakers apparently went out. I tried to use the other working amp to power everything. I used the same grounding and power connections but then I got a whining noise and poping noises. I tried every kind of hook-up that I could but nothing seemed to help. I even checked out my battery and alternator and was checked OK. I also took out the stereo unit (Pioneer supertuner) and ran a patch cord to the amp and when I turned on the truck I still heard that whine. It goes up and down with the RPM of the engine. Could it be something else?

Answer
Robert,

  before i give you the quick fix go over all your wiring make sure everything is tightly spliced and wrapped good with electric tape.. also make sure your speakers are wired properly for use with the right ohm of your speakers here are some diagrams on a help site i have
www.geocities.com/evilparadise02/stereo.html
ok after all of this stop by radio shack and buy a noise eliminator or distortion blocker set you back about 10 bucks and wire one of those or even both if you want and that should fix the whine noise you are getting .. hope this helps you out if you need anything else let me know

thanks