noise reduction tool

Using 1.3.11 In the “Effects” main menu there is a noise reduction tool that puzzles me a bit.
First step is to collect a noise sample. It prompts: select a couple of secs of noise and click on “load noise profile”.
Now if I select an area and do “load noise profile” I can see no response from the command, whether if I only select a spot with a marker I can see a creating noise profile green working bar that shows the progress.

I find this very confusing. Does the command work for both selection methods and why doesnt the work-in-progress green bar show up when selecting an area, which according to the prompt is the proper type of selection?

Does this explain it sufficiently?

See this page from the Audacity 1.3/2.0 manual:

and this page from the Wiki:

There are some of us who think that it should be a single consolidated process (with extended dialog) rather than the somewhat confusing 2-pass process - IIRC there may have been a feature request along these lines posted a while back.


Well it seems rather clear from the manual that a region should be selected.
The only thing confusing is that if you pick a spot the command acknowledges that it works on your (faulty?) input
whereas when you select a region (the proper input) you don’t get any such acknowledgement.
If it wants a region, why does it accept a time spot?

By default, when you use an effect without making a selection in the track, the entire track will be selected.
What is probably happening is that the Noise Removal effect is processing the whole track and obtaining its “noise” profile from that. That will take a while for it to do, so you get a progress bar. When you (correctly) select a noise sample and make the noise profile from that, it happens so quickly that there isn’t time to show a progress bar.

yes, that sounds very plausible. As I remember it there was no clear evidence that the command was malfunctioning when I didnt select a region and then applied the noise reduction, but there seemed to be a reduction even then. So a nice upgrade would perhaps be to add an input type check before producing the noise profile?