Lexus IS350 - Rear Speaker buzzing at high bass
 

My rear deck speaker has been buzzing at high bass after an oil change (I don't suppose the oil change would have anything to do with it but could it?)
How do I make sure it is because of a rupture before taking it for a fix? I'm assuming I have to replace the entire rear deck kit which would require removing the back seats?

Model: 2007 Lexus IS350