Question about removing sound

So, forgive me if this is a dumb question as I’m pretty new to this kind of things such as editing sound files but I actually got a question.
Is it possible to remove sound within/above/below a certain decibel range? For example, let’s say that I want to delete/mute every sound that is below 20 dB, is this a possible thing?

You may be looking for a noise-gate, you can free a noise-gate plugin for Audacity here.

Probably not in the way you mean.

let’s say that I want to delete/mute every sound that is below 20 dB, is this a possible thing?

There’s Effect > Noise Gate. That one can sense if the overall volume of a presentation drops below a certain value and drops it the rest of the way to zero or some lower value. In practice, it sounds like a bad police radio.

The only way I know to suppress low volume sounds during higher volume sounds is Effect > Noise Reduction and that one only works on constant, background sounds like air conditioner or computer fan noise—and then only if they aren’t very loud.

There are no good ways to convert a man-on-the-street recording into a quiet studio presentation. One good way to kill a voice recording is leave a TV on in the background—even quietly. Any constantly changing noise is deadly.

So yes, you do need to record your audiobook or podcast in a quiet, echo-free room.

You can throw money at the problem. There are some really good microphones that can ignore environment noises. This is a shotgun microphone being used in a non-studio interview.

I forget the model number, but I believe that one runs about $1000, and it’s an XLR type, so it needs to plug into a formal field sound recorder.

Koz