Laptop Questions? Ask a Laptop Technician for Answers ASAP!
Hi, my name is*****'m sorry to hear you're having this issue.
For an issue like that the exact reason would be impossible to say without doing some hands-on troubleshooting, but from your description it sounds like it would be a hardware issue of some kind. It could be an issue with the soundcard/motherboard, or it could be something with the wiring, or it could be something with the actual speaker itself.
I wish I could give you a more specific answer, but for an issue like that you really would need to have a technician do a hands-on diagnostic and try to trace down the problem, but just based on what you've said it sounds like the speakers may need to be replaced. You can take the computer to any authorized Apple service provider for further assistance.
If you have any other questions on this, just let me know.
No problem, happy to help!