I run a movie theatre and use WavePad to make the showtimes recording. I have been doing this for a number of years with no problems, but recently starting having all kinds of problems with consistency.
My normal routine is as follows
Close my office door and turn off anything making noise.
Create a new Mono recording.
Record the script, pausing at the end with about 5 seconds of dead air.
Select the dead air at then end and Noise Reduction>Grab Noise Sample
Select the entire recording and select Noise Reduction>Apply Spectral Subtraction