>>11462537wildly depends on application inside the room, they can either deflect, absorb or diffuse sound waves, separately or all together.
bass usually builds up in corners, so if you have dense foam in your corners you can lower the room gain most rooms have and have a more linear response.
foam usually absorbs mid and high frequencies.
anything less than 2 inches thick will be practically useless. it doesn't have to be egg shaped, because they absorb and not diffuse the sound. the egg shape thing serves as two purposes, first it propagates the meme that this shape is the only viable shape for an "acoustic foam" panel, second it cuts their costs down as they can claim it to be a 3 inch panel while infact the crevasses are half that size, while a solid 3 inch panel would be twice as effective at absorbing.
>tldr this is meme foam. slightly more expensive stuff would be denser and flat surfaced. 
