Silence the low sound parts automatically

When I analyse a recording with Audacity it can easily find places where there is (some kind of) silence. This can e.g. be done with the “silence finder”. When I look at these places in the recording I almost always want to flatten the recording on these places because I can hear breathing myself or there is some background noise I want to get rid of.

I now do this by the button “silence audio” and that works fine.

What I would like is that there was a function where I can automate this process. For long recording I can’t do this with this one button function. I did use the “truncate silence” but there I can only truncate the silence places and not flatten (cleaning up) them. Most of the time the sound is part of a screen recording and must keep it’s length to easily synchronize with the video later.

Is there any way I can automate this process with Audacity? Maybe there are options outside of Audacity to accomplish this?

Any help welcome,

Yes, you need to apply a “Noise Gate”.

A Noise Gate is an effect that “lets through” sounds that are above a certain threshold level, until the sound level (amplitude) drops below the specified level. When the sound level falls below the specified level, the gate “closes” and reduces (or stops completely) the sound from getting through. Thus, higher level sounds pass through the gate unaltered, and low level sounds are blocked (silenced).

There is an optional Noise Gate plug-in here:
Instructions for downloading and installing:

Tip: forcing the quiet parts to absolute silence can sound unnatural and a bit “disturbing”, so noise gates are not recommended for audiobooks. The noise gate effect suggested can be used to “reduce” or “totally silence” the quiet parts - generally it sounds better (more natural) to just reduce the noise a bit rather than silence it completely.