Is there any program that is able to do so?
The case is to record everything in the room with the computer, BUT exclude the sounds, produced by the computer itself (film sounds, skype sounds, incoming call sounds, system sounds, etc.) /maybe, correct is to EXCLUDE MASTER OUT.
Optionally, reduce computer cooler noises.
Optionally, record only when voices appear. “Level-Activated”, skipping silences.

Record from MICROPHONE

Record what from the microphone? Are you singing? Recording an AudioBook?

You want a studio:
A comfortable, air conditioned, quiet room with no echoes.

Audacity doesn’t do anything in real time. So no noise reduction or filtering as you record.

Once you get the bad recording, it will pretty much stay bad forever. Having competing noises in the same room with a recording is one of the guaranteed ways to kill a podcast. If all you have is gentle, unchanging computer fan whir, you can help with Effect > Noise Reduction. But if it’s loud, that tool will start to distort voices.

Having another “show” (computer sound effects, Skype voices, etc.) competing with your show is fatal. There are no rescue plans for that which don’t also distort your voice. If you’re trying to sing, you’re dead. There’s no gaps between words to do processing.

You can try Effect > Noise Reduction and Effect > Noise Gate. Those are the two tools that are closest to what you want.

I don’t see Noise Gate listed. That may be a download.


Actually, it’s most common to record from one device/input. See [u]Tutorial - Selecting Your Recording Device[/u].

And again from studios, wear headphones so the computer show only appears in your ears and not in the room.

Then pick a carpeted room with as much furniture and drapes as possible and then put the computer as far away as you can. One of the reasons I have a Mac is it makes no noise while it’s recording.

This is the recommended setup for recording audiobooks from ACX. Note the Mac right next to the microphone.