Noise elemination

Hello Fellas

Actually I am Audacity owner, and I am playing with own software, and I need your advice.
The audio card is in recording mode from a mic.
The DSP mode is Mono, 8 bits + 22050 sample rate. When I play that signal I have quite thick noise on top… Shhhhshhhhshhhhshhh!
It’s level is balancing in between 127-128-129… seems like correct ZERO…
How can I remove that noise? Just to make it as silence… Should I control the playback and simply do not play any when the level is about at that values? What would I substitute instead of that values to make the data feeding process uninterruptable and to get the silence as the result? Is there a value that means the silence for playback? (I guess no ))) but need just your suggestion and clarification.
Thank you.

P.S. So let’s say we have the desire to suppress the voice below 30 db… how can I get the digit over and below zero base (128) that is equal to 30 db value?

In other words - how to say to a sound card to filter (skip samples) with values over and below the zero base (128) at the same absolute value, say 20?
Should I normalize all values over and below 128 at step=abs(20) to the absolute zero = 128?
Ytied that without success,seems like all values are important.

Audacity does not do real-time processing. You could use a “Noise Gate” to silence sound below a specified level. There’s a Nyquist plug-in here: Missing features - Audacity Support

What device is that?

Understood… Well now 16+32000 = pretty fine.