This started on another forum where everybody went off about how egg cartons on the wall "do nothing for the room and are a fire hazard".

My take is this. While I do not contest that acoustic foam is the ultimate sound control wall surface, some of us don't have several hundred dollars to buy such an item that in a home studio environment is really an overkill frill. I have always believed that ANYTHING on a wall that will disturb a smooth surface pattern is better than the hard face of the drywall that is likely there now, so why not cardboard egg cartons? The goal is to make the room anechoic, correct? All the anechoic foam wall material I have ever seen is the wedge shape, and I have to ask the people here who work in real studios this simple question.

Is it the SHAPE of the foam that baffles the sound, the material itself, or a combination of both? Now, for me, everything I record is direct anyway, so it isn't a big deal.

I have seen room baffles made of foam squares of different sizes and heights all glued in a random pattern on a 4x8 surface. I have also seen curved plexiglass room baffles placed at random locations, I suppose to create round reflective surfaces rather than just the 4 square corners of a room.

I studied music, not acoustics, so I have no clue, just what I think is logical. After years of watching people hang blankets, foam mattress pads and every other absorbent surface on walls, I'd like to ask people who actually know for their opinions.