This question already has an answer here:
How can you disable the startup-sound? I mean the drums when you login. Edit: I have tried disabling Gnome Login Sound, but it keeps drumming.
And also set the volume to muted so that it sticks? Now when I press mute on keyboard the first keypress seems to lower the volume instead, and thus plays a sound. Second keypress works.
I would like to start without any sound at all.