What is "Visualization of Sound Effects" and how do I turn it off?

Visualization of Sound Effects shows on-screen indicators pointing to where sounds around you are coming from — gunshots, footsteps and other noises. Your own sounds and those of your team and clanmates aren't shown.

To turn it on or off: Settings → Audio → Additional → Visualization of Sound Effects, then pick Off or On.

You can change it during a match too, from the pause menu. It's also on the Favorites tab.