How to fix noise cancellation?

Question

macOS

Recently, noise reduction on the Mac has started to work in the opposite direction. All sounds are heard, and the voice is suppressed (it is heard but many times lower than it should). What could be the reason for this and how to fix it?
Available Macbook pro mid2012 with El Capitan on board.

Answer 1

Internets say that this is an iron problem.
to start apple.stackexchange.com/questions/90123/internal-m...