It's not quite as many different things, but I usually need music or podcasts in my ears while doing something else. Sometimes it's just noise; I occasionally have to rewind to check a joke or fact I missed while my focus increased on something else. If I don't have the stimuli, I find my mind wandering in worse ways though. Driving and a podcast help me focus on the read and not get highway hypnosis or looking at every single thing. Podcast while gaming helps me keep focus on anything somewhat mundane in the game (this varies by game, but most games aren't 100% pumping 100% of the time).

If I really need to focus on something, then podcasts are a distraction that gets turned off. Music also fits this roll, but depending on how much focus I need I may end up changing from music to lyrics to instrumentals.if I have no external extra stimuli I find myself getting bored, mind wandering, etc. So it helps me focus by having a second input my eyes don't need.

I can't do two visual inputs at once, nor two audio inputs. But I usually need input from both. Oh, and the fan thing is incidental. My room produces more heat so I have a room a/c running often, and it's also a white noise generator I guess. It doesn't run in winter so it's not always on, but this time of year it's a regular noise for me.