Macbook air microphone picks up computer sounds
My MacBook Air microphone picks up the computer sounds along with what I speak, even if I use headphones. I've checked for this in system preferences, Skype's echo testing system and Discord's settings, and the problem happens the same in all three cases. Any sound that's being played through my computer such as youtube videos, music or game sounds, gets picked up loud and clear along with my voice.
How can I make it so that the only thing going into the microphone is my voice?
All tests were made with a set of iPhone headphones.
MacBook Air (2018 or later)