Why is the connection between the camera and the external microphone sometimes noisy?

There are many reasons, such as the length of the microphone wire and whether the contact is reliable. Sometimes this happens when the microphone wires are crossed together. If the external microphone is battery-powered, you need to copy and turn off the +48v switch on the camera, otherwise it will burn out the microphone after a long time. If the battery has electricity, it depends on whether the battery is sufficient. If there is a fluorescent lamp at the scene, its vibrator will also affect the external microphone. When recording, the landlord had better listen with monitor headphones, and then manually adjust the audio input. It is related to the tightness of the interface, and the other is the setting. It doesn't matter if there is a little noise in the current, just reduce the noise of the audio filter later.