Insulating the bells hinder sound?

Looking at mounting K3’s inside where my spare tire was on my Prius. I’m going to cut 3 holes through to the outside where each bell goes with each bell barely sticking through to the outside. Then I’m going to “insulate” around the bells with foam, fiberglass insulation, or something of the sort to help with sound inside the car.

Will doing this affect the sound in anyway from the outside?