I record YouTube videos, and I use Audacity to record my voice. I like to turn the mic volume down, that way the background noise from my PC fan/bedroom fan can’t be heard on the recording. However, this little technique is pretty problematic when it comes to recording with friends. Whenever I turn my Audacity mic volume down, it automatically turns my microphone level down as well. Making it so that my voice is super quiet when talking to my friends. Of course, this doesn’t hurt me in the slightest, but it can sometimes hurt my friend’s videos as my voice will most likely not be picked up by their recording software. Is there a way I can prevent Audacity from tampering with my microphone levels? All help is much appreciated! 
I’ve read this three times and I still can’t make sense of it.
If you turn down the mic, then how does Audacity hear your voice?
Well yes. If you turn down the mic then would you not expect it to make your voice quiet?
You started off saying “I like to turn the mic volume down”.
If you don’t want the mic to be “super quiet”, then don’t turn it down.
It isn’t tampering. When you select the mic device in Audacity, the recording volume slider in Audacity is meant to adjust the level of the mic slider in Windows. And you only have one mic, so you don’t have any choice.
If fan noise is a problem at higher recording levels it can probably be removed after recording with Noise Reduction.
Gale