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

My understanding is that they are not so much for sound proofing but to reduce reflections (echo).

Sound proofing a room requires a great deal more work, the room needs to be air tight (with proper ventilation), walls need to be constructed with heavy materials and ideally, a double wall with airspace between – and no hard connections between the two.

Doors need to be heavy, with good seals, and windows need to have multiple panes, but not parallel to each other.

In other words, a whole lot of work goes into actually making a sound proof room. Sticking foam on the walls doesn’t do it.