How does sticking weirdly shaped foam blocks on the walls of a room make noise hard to hear from inside and out?

Question

How does sticking weirdly shaped foam blocks on the walls of a room make noise hard to hear from inside and out?

In: 13

Answer 1

they also use sheets of plaster/gyprock with row upon row of small holes drilled right through them.. I asked the sound tech about it and he said it’s about breaking up the soundwave, because otherwise walls can just act like a drum