There are multiple known examples of running code which does soundcard communication - see e.g. https://github.com/borismus/sonicnet.js. I can personally verify that it required no special handling to work on two laptops made by different manufacturers running different operating systems in a noisy room.

This doesn't mean that BadBIOS is true — only that it's annoying and tedious to play the skeptic with shoddy logic and trust-me assertions being presented as facts.