It looks like the fix may not be limited to Apple Stores and affiliated repair shops, either. MacRumors notes that Apple has already published an M4 MacBook Pro speaker repair guide on the site ...
If the issue persists, it may be hardware-related. In that case, you'll need to visit an authorized service center to have a technician inspect and repair your phone's speaker.
In MacBook Pro models before Apple silicon, the whole top case of the MacBook Pro had to be replaced if a speaker needed repair. That meant that a customer had to pay for replacing parts that didn’t ...