1) First, go work on your paper
2) Forget the sounds changing, thats really bizaare stuff
3) Lathering is way easy
4) I think you've made a this-then-that correlation between changing bowls and lather that doesn't make sense to me

Try it this way

1) Put warm water into the mug
2) Soak the brush and squeeze that water out
3) Dump the warm water out of the bowl with the soap
4) Rotate the brush briskly in the soap dish
4) Add a little water if need be by dipping your fingers into the sink with your shaving water and then flicking them over the bowl.
5) As you add water eventually the soap with explode into a more lathering product
6) No changes in sound, pitch, harmonics or any other cosmic events