How to create a virtual sound adapter?

Question

linux

Hello! There is a car on which there are no sound adapters at all (okay, virtual machine), and you need to record video from the screen with sound recording (for example, a player with music plays in the FireFox browser, the sound of which needs to be recorded). It costs a pulse, but she doesn’t know how, and the screencaster says that there is no sound adapter.

Answer 1

Connect a sound card from another machine to pulseaudio over the network ???
What hypervisor? Most are able to emulate sound.....