help With My Radio Save Me

i have a 94 maxima and i bought it with no deck so i went out to buy a deck and when i went to put it in all i found was towo sets of wires it seemz i got it all in ok but when i turn on the car to auxilary it works
and when i turn it on to ignition i get a wierd sound out of my left top speaker i dont know what could possibly be rong i need help mabey someone who has a wire diagram please anyone help!!

That could be a number of things, ranging from faulty wiring to a bad alternator/voltage regulator.

does it fluctuate with the revving of the engine?