Whining sound when I plug in my aux cord in my car

[AC Question]

So the other day I'm in my car and I plug in my aux cord I use my beats by dr dre cord which has never been a problem and I use a Walkman MP3 player. Well when I play my music I can only hear my music out of my driver seat speaker and not so much in the passenger side speaker sometimes there is a static sound. Now when I play the radio it seems like the left speaker is fine only when I plug in my aux cord. What could this be? Do I need to replace the speaker on my passenger side of my car?

 

[B. Diddy]

Welcome to Android Central! Are you certain the aux cord's plugs are pushed in all the way, both in the aux jack of the car and in the headphone jack of the MP3 player? Sometimes, if the fit is very snug, you might not realize the plug isn't in all the way.