Block Auto Noise Reduction

Audacity appears to be automatically filtering what it recognizes as “Background Noise” and I want to stop this.
I am recording music that includes a sustained drone of one note for an extended period of time. When recording, the program picks it up for roughly five seconds, and then it immediately filters this out (the drone fades out and then only micro variations in pitch show up).
After this, on subsequent recording, the drone is filtered out immediately. In addition, a drone one musical fifth above that note is also filtered out immediately (I presume the algorithm works in overtones too).
Is there a way to prevent Audacity from filtering this out? It is not background noise and I would like it to be treated as such.

Audacity doesn’t apply effects or filters in real time, so that leaves it up to Windows.

Windows voice processing has been known to do that.