What would be the best "egg-carton" acoustic treatment method?

Question

We are working on treating one of our "studios" at school, which is used for video recordings.

The reason behind this project is that it currently sounds like a bathroom.

We have thus collected stacks of egg-cartons (I am actually quite aware of the limitations and why it is usually not recommended... Apparently, it is at least effective at around 640Hz.) We have actually received quite a lot from a local chicken farm, so we are going to continue nevertheless!

What side of the cartons should be facing forward? (The side that holds the eggs or the reverse? The reverse seems like a better idea, as the texture is more rough.)

The cartons are also going to be painted for aesthetic reasons. What paint should be the best, considering acoustics? I recommended a matte finish, but I could not name any specific type.

Also, what would be the best method to attach the cartons to the walls? We have considered glue gun or "sticky gum" (not sure what it's called - blue tack or something) as well as affixing the cartons to a plywood sheet and then standing this sheet up against the wall.

After the egg-cartons, what would the next step be? I have read that bass traps might be necessary, but in what specific scenario would that be recommended?

(Just for extra context, the room is partially carpeted and contains a variety of furniture.)

Please take into account that this project is running on minimal or no funds.

Thank you in advance!

Answer 1

You need to ABSORB sound partly to reduce, and partly to keep it from bouncing around (which is why it sounds like a bathroom). So THICKER things like heavy curtains or moving blankets (or quilts) or even old mattresses propped up against the wall have been effective.

If you MUST use egg cartons (which you already know are not very effective), then at least them to better advantage by spacing them our a few CM from the walls. The air trapped behind them will soak up some of the sound. And don't REDUCE whatever absorbing properties they have by sealing up the surface with paint!

If you want to color the cartons, use vegetable dye as used for dying cloth. Getting the cartons wet will also open up the porous surface a bit. Definitely use the BACK side (the rougher surface).

Note that there are several inexpensive "home made" treatments you can use to make the egg cartons more fire-resistant. You could even combine coloring the cartons with fire-resistant treatment.

DIY fire-resistance: http://www.wikihow.com/Make-Cloth-Fireproof

Answer 2

Egg cartons won't do much of anything. There's a lot of research on this on sound engineering forums. Get yourself some acoustic panels instead.

Answer 3

I covered my dorm room with egg cartons when I was in school. We used contact cement or a tough rubber cement (I think it was called "Goo") to stick them to the walls and ceiling. I agree with the idea of doubling the layers. you should also stagger the crates to cover the joints in the lower layer. Besides all the other disadvantages mentioned above, I will remark that our installation proved to be an attractive habitat for insects.

Answer 4

I considered doing something like this at one time, but after much reading I decided it probably wasn't a good idea to use egg cartons, and instead ended up with something a little more professional (fibreglass panels).

You mention that there is some carpet in the room, and furniture as well. This is good since it will make your room sound less like a bathroom. Couches, or bookshelves full of books will go a long way in absorbing sound and keeping it from bouncing around the room, hopefully making it sound more natural. Try not to deaden the room too much though.

Important: What I'm about to suggest is purely experimental, and highly dependant on how many egg cartons you have available.

Fibreglass panels are a great solution. Perhaps we can try emulating this with egg cartons! Maybe it's a bad idea, but it doesn't hurt to try, right?

Now, the thing about fiberglass panels, is you don't treat the entire wall. Instead, they tend to get spaced around the room something like this:

This might not be very effective with egg cartons because fibreglass is a much better absorber, and it's thicker, denser, and heavier. To emulate this, you could try layering your egg cartons together into panels (make them big and heavy), and space them around your room in a similar fashion. I would think this would be more effective than just plastering all the walls with a single layer of egg cartons. If you have the cartons, I'd be curious to see if this works.

Answer 5

If the room sounds like a bathroom, you need to dampen the reverberation(sound waves reflecting off the walls).

The best, no budget method would be to find heavy materials, like thick curtains/drapes, foam or cushions and hang them on the walls(hang the curtains as if there are windows there). You could increase the effect by placing the cushions on the walls, behind the curtains.

There are many good answers on this site about sound dampening & room treatment using everyday materials.

NOTE: This is different to sound proofing.

Answer on Sound Absorbsion/Dampening (similar subject)

Answer 6

First, if you do use the egg cartons, you need to use a flame retardant treatment like FlameStop on them before you put them up. Else even a small flame in that room would result in a deadly fire. Don't worry about inspectors catching you, worry about dying. Or, getting burned really badly and NOT dying, which might be worse...

http://www.flamestop.com/

When I was a teen working in a summer camp radio station, we used egg cartons on our studio walls and ceiling. Free from the camp kitchen. Yes they helped. They are most effective in the midrange so it was good for radio announcer type stuff. They don't absorb bass at all or highs too well.

We used hot glue to stick them on our bare plywood walls. Once in a while we'd have to reglue one. If you have painted concrete walls, rubber cement would probably be better.

I actually wouldn't paint them because I think it would make them stiff and fill their pores.. reducing the little absorbtion they have. You could try dying them with fabric dye if you want color. But do that first, before you spray the FlameStop on them...

Answer 7

You can use acoustic panels for walls. Acoustic treatment is usually done on walls or ceilings. Acoustic panels for walls are widely used in classrooms, recording studios, conference rooms, hotel lobby, auditorium, education facilities, leisure centres, reception areas, studio sound, and so on.