Internal Speaker (Subwoofer) of my MacBook Pro (13-inch, Mid 2012) is delivering cracking sound

Hi,

Internal Speaker (Subwoofer) of my MacBook Pro (13-inch, Mid 2012) is delivering cracking sound every time when I play any video/audio file, after opening back cover of my macbook pro, I found that this internal subwoofer is bouncing highly from its position, seems like it will come out any time from its position and continuously making this cracking sound. So please help me to resolve this issue or show me the proper guideline at the earliest.

Attaching the internal subwoofer pic for your reference, it's marked with red line.