Does anyone know how to so called "Creative Mic Spam"?

[COMBOBREAKER]

hello ladies and gentlemen, i have seen this so called creative mic spamming/ live voice remix stuff done on multiple games, whether it be Gmod or call of duty and such. anyway i was wondering if any of you know how they do it because i have always wanted to.

[URL="https://www.youtube.com/watch?v=uUYJe2m5jlA"]Here[/URL] is a video of someone doing this on a Gmod server

thanks in advance.