Whispering voice in disrupt's older videos

Hi, didn't want to make a post her but I couldn't find my answer by looking elsewhere so if anyone know please let me know?

How is this effect done? The whisper voice used in a lot of the older videos for titles and names of important topics inside the videos, for example in this video https://www.youtube.com/watch?v=7kPNVKqSGz0&t=369s&ab_channel=Disrupt at 6:09.

If anyone know please let me know :D
Thanks!