Ford Ranger 95' ,High pitched Whine noise through driver side speaker ,gets

[James]

louder while driving.? i have a 1995 ford ranger with a aftermarket stereo installed. the speakers are new as is the radio/cd player. when ever the key is in and the truck is on.. a high pitched noise comes out of driver side speaker (only). all the connections for the speakers are fine. all connections are correct. i checked ground they were fine .. then made a new ground . still the noise is their.. installed inline noise filter..didnt work...alternator is good when truck is on Accesory no wwhine. Any suggestions as to what i should try next