The sound is bad

@heman1687 could be caused by a loose speaker or a broken speaker. You will have to open it up and take a good look at it. Use something like this video to disassemble your speaker. Then take a look at the individual speakers to make sure they are properly mounted and that the cones are not cracked etc. Post some good pictures of what you find with your Question. That way we can see what you see. Bilder zu einer vorhandenen Frage hinzufügen

While you work on your speaker, take lots of pictures. Once you are done with it, take those pictures and create a guide for iFixit. That will help the next person that has the same problem as you do. It's easy and fun to create these guides. https://ifixit.com/Guide/new The iFixit community will appreciate this.

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