Gdm3 & Alsa: Toggle speakers off remotely, from shell

Today I’ll stay home instead going to the Amsterdam office. I have a terrible headache and i stay better on the dark-silence.
But i want to stay in touch with the office so i start my email, chat, and other web apps, but  suddenly I realize that probably in the office, my colleagues hear...
Gdm3 & Alsa: Toggle speakers off remotely, from shell