@kuleshwar could be a bad speaker coil or ripped speaker cone. You will have to take it apart and check the speaker separately. Of course there is always the chance that this is a bad amplifier (IC or circuit) again you won’t know until you check. Take a look [https://www.youtube.com/watch?v=Ka1VO_4buB4|on here] for a teardown. After that post some good pictures of your pieces with your QUESTION so we can see what you see and possibly help you further.
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