An extended note gets changed

Whenever I play or sing an extended note on audacity, and by extended I mean anything more than 3 seconds, this program changes how it’s recorded, usually to a softer amplitude. It sounds as if a glass shield is suddenly put up between me and the microphone. It doesn’t matter what the sound is or how far I am away from the mic. I don’t change my position from the mic or the volume of the sound I’m making and it still does it consistently. I can’t find anything in preferences that would change this or stop it from happening. Has anyone ever experienced this or does anyone know how to change it/stop it from happening? Thanks.

Please see the pink notice above which says:

Please state which version of Windows you are using, the exact three-section version of Audacity from Help > About Audacity

If you are on Windows Vista or later, this might be the answer: .