This is usually caused by the function of "Automatic Gain Control" or "AGC" on the camera. Basically, when the camera cannot sense an audio input signal it automatically increases the gain of the input. It is increased so much that the noise floor in the camera microphone amplifier becomes audible .
How do you reduce background noise on a rode mic?
https://www.youtube.com/watch?v=BPiQIVuRRYI
How do I stop background noise on my mic?
Under the “Recording” tab, select the mic you're using and tap “Properties.” Go to the “Levels” tab. If you're experiencing a lot of background noise, reduce the “Microphone boost.” Try reducing it to +10.0 dB. The mic will now be more sensitive to your voice, but it will also pick up background noises easily.Jul 19, 2021
How do I remove background noise?
https://www.youtube.com/watch?v=rWbxyshpnbQ
What is dB on Rode mic?
The term dB SPL is used to show the measurement of sound pressure. It is a logarithmic measure relative to a reference value of 20u pa, which is accepted as the level of human hearing at 1kHz.
What does dB mean on a microphone?
dB or decibel is a relative unit for the quantification of the audio level or audio level change. As it is based on a logarithmic scale, it more or less indicates levels as perceived by the human hearing. Each unit of the dB-scale represents a factor.