I am sure this has been asked before, but I could not find the correct search terms.
I'm not exactly sure how to phrase this question, or if I am even asking the right question, but here goes.
If a panel has the correct geometry, say, a skyline diffuser, but it is made out of soft foam, will it act as a diffuser?
Seems to me, if the material has absorptive properties, like foam, that will mostly override the shape of the surface. How will the sound diffuse, if it being absorbed by the foam?