Interesting, you never step learning. Looking into it, the used algorithm is called spectral noise gating and it is actually quite simple. I should really get more into audio signal processing. :-)
This is a good place to start:
This channel, along with Curtis Judd Audio, is very good, I learned a lot from this guy. At one point it basically saved my recording, it was a concert in very unfavourable conditions, and with constant hum from nearby lamps.
Edited by Judith, 06 March 2017 - 05:02 AM.