How to UnRobotize after Effects > Noise Removal

Here’s the problem:

I’ve removed BG noise from a clip using Effects >Noise Removal
and the “Get Noise Profile” and then the “Noise Removal”
My goal is to have just voice and no BG sound.

The noise is removed fine.
Now everything is slightly “robotized”, including the silence where the noise used to be".

Any tips on un-robotizing what I have left?

The Noise removal in Audacity 1.2.6 is generally more prone to “robotizing” than the effect in 1.3.12
In either case, all you can do is to use less Noise Removal (reduce by a lesser amount) so as to reduce the unwanted audio artefacts. There is no satisfactory way to remove the artefacts once they have been created (apart from “Undo”).

Sometimes increasing the “frequency smoothing” can help to reduce the formation of these unwanted effects, but the main thing is just how much noise you are trying to remove - the more noise that is being removed, the worse the metallic bubbly sounds will be.

Noise Reduction is not going to turn a messy recording into a studio track over a velvety silent background. Usually the best you can do without show damage is suppress the noise – sometimes only a little bit. People who overdo these settings usually get Martians or gargling aliens for a show.

The noise and the profile capture make a big difference.

If your show is people talking and the “noise” is people talking in the background, That’s not noise. All those people are performers and you can’t separate them.

You can’t separate changing noise. Constant air conditioning hum or whine and microphone hiss or hum are OK, but the Metrobus starting its engine and departing outside the window is now a performer in the show.

People tend to think of “anything I don’t want” as “noise,” but noise is strictly defined and usually awkward.

The profile step is very important. Whatever sound you select as the profile is the sound that Audacity will try to subtract from the show. That’s why the performers have to shut up long enough to get a sample of background noise without them and also why doing this in a finished show is almost impossible. All the good quiet bits have been removed in editing.

The good working noise removal is in Audacity 1.3.12. The earlier ones were interesting engineering exercises. You don’t always have to use Noise Removal. Threshold Keyers and Noise Gates can be useful, too, and a lot less likely to sneak weird sound into the show. They drop or suppress any sound below a certain volume.

Steve wrote one here…

…and there’s a way to make Chris’s Compressor do one, too.

Chris’s Compressor

One last item. Noise reduction and DC suppression have to be done first. You can’t cut the show and add effects and only then try to use those two tools.