Changing footstep sound on different surfaces with FPS controller

Ok i'm trying to figure out a simple way to let the standard FPS controller change footstep sound depending on surface. Ive looked at terrain and collider methods. So far all Ive found are systems that work with custom character controllers or third person controllers.

Basically I need a behavior so when the character is in a collider the footsteps change then go back to default when they leave the collider with the standard FPS controller.

I'm completely stuck and so far all Ive found is answers from 2010 and ones that don't work with the standard Unity FPS controller. Ive managed to get away with a single footstep sound so far but that's not going to fly from here on out and I desperately need help. I'm not terribly good with scripting beyond basics so yeah, I really need help.