I seem to know a lot of people who I would characterize as loud gum-chewers.  A loud gum-chewer chews gum likes it's the first piece of gum ever chewed.  It's loud and obnoxious and everyone notices it.  It's like when you give gum to a little kid.  The kid shoves that piece of gum in his mouth, then chews it like he's trying to tear apart a wild animal.  The non-stop action consumes him, and every person in the room knows about it.  His loud chewing is evident while talking, walking, breathing, thinking.  Gum-chewing is a special event for this kid. 

My 60-year-old co-worker is a loud gum-chewer.  I can't not notice it.