Audacity 4 documentation · Primary-source explanation; examples are illustrative. Instructions are based on publisher guidance; a UK IPTV account was not tested on this platform.
Find a representative pause
The current Audacity manual describes Noise Reduction as a two stage operation: capture a noise profile, then process the intended audio. The profile must contain the unwanted steady background alone. Selecting a whole spoken sentence because hiss is audible underneath it also includes the voice in that training material. The documented effect suits steady noise such as a fan; a single door slam is a different restoration problem.
Listen to what would be discarded
For an original exercise, duplicate a permitted voice recording and locate a pause with the same background as the neighbouring speech. Capture that isolated background, select a short passage containing quiet words and compare a modest reduction. The current dialog includes a Noise only output for checking the removed material. If recognisable wanted words appear there, undo that checking output and revise the profile or settings before producing the cleaned version.
Judge intelligibility as well as quietness
Compare the processed passage with the original at a sensible listening level. A lower background level is not an improvement if consonants become unclear or metallic artefacts dominate. Apply the chosen reduction to the intended region only after this comparison, and retain an unprocessed source for a later attempt. Check another passage if the background changes during the recording. The aim is usable speech with an understood compromise, rather than the largest possible reduction number or a promise of complete restoration.