HELP: absorption coefficients of "popcorn" ceiling?

[LAstudio]

Anybody know the absorption coefficients for a popcorn ceiling? I'm helping a friend set up a home studio space...

[Glenn Kuras]

I would say just around ZERO. It will not really do anything, absorb or diffuse.

[Ethan Winer]

Originally Posted by LAstudio

Anybody know the absorption coefficients for a popcorn ceiling? I'm helping a friend set up a home studio space...

As I explained in reply to your PM, a popcorn ceiling is acoustically the same as a flat ceiling. In order to absorb you need either "fuzzy material" or a vibrating membrane (or vibrating air column). And to diffuse you need a pattern with a depth approaching 1/4 wavelength of the lowest frequency you want to affect. So in that light, I guess a popcorn ceiling diffuses very well around 45 KHz and higher.

--Ethan

[andrebrito]

What is a popcorn ceiling for you guys ?

There a material that is sprayed in the ceiling that makes the ceiling like a popcorn and it absorbs mid and high...

[Ethan Winer]

Originally Posted by andrebrito

What is a popcorn ceiling for you guys?

It's tiny sand pebbles that are mixed into the paint to give the surface a slight textured appearance.

--Ethan

[Weasel9992]

Originally Posted by LAstudio

Anybody know the absorption coefficients for a popcorn ceiling? I'm helping a friend set up a home studio space...

Like Ethan and Glenn said, functionally exactly the same as a flat sheet rock ceiling.

Frank

[Rod Gervais]

Originally Posted by andrebrito

What is a popcorn ceiling for you guys ?

There a material that is sprayed in the ceiling that makes the ceiling like a popcorn and it absorbs mid and high...

Andre,

been around this a long time - and don't know of the material you speak.

Popcorn ceilings have 3 textures I know of - fine, medium and coarse - and the coarse spray is not 1/10 th the size of popcorn itself - can't see how it would diffuse much of anything - and the styrofoam pellets they use (popcorn ceilings use foam pellets Ethan - a sand finish is a different application by trade name then a pocorn finish) can't possibly absorb much at all in anyting but higher frequencies.

Do you have any reports you could turn me in to?

Rod

[fredv]

Just a thought, what about the spray material that looks like chopped up paper towel? It's not Auralux, but it's better than nothing.

We had the material sprayed on in an equipment room ceiling, which was actually the metal deck for the roof. It sticks right to the ceiling, and when applied over three days is about 1.5" thick. It definitely took down the echo and the sound level in the room. They use this product in high school gymnasium construction.

I also added some sound panels suspended from the grid by nylon fish line to help in areas where I could detect some reflections.

I would consider this a last resort if there is nothing else available. Plaster popcorn or knockdown ceilings do nothing to change the sound

[LAstudio]

Thank you guys for clearing that up. And thank you Ethan for the PM.

[MusEsq]

Hey - I would be more concerned that the "popcorn" ceiling contained asbestos than determining its sound properties. Here in California it was used until the late 70' to hide imperfections in the drywall/tape joints in ceilings. Please don't drill, scrape, wet scrape, sand or otherwise disturb it until and unless it is tested by licensed asbestos abatement professional. Regular "dust masks" don't cut it!

Just want you guys to be around to make more music. Take care...

[Mr.Smith]

From my understanding of this post, I think the proper trade name you are looking for is Stucco, which doesn't contain asbestos.

I would also tend to believe that it won't do much to the sound, and if so nothing very audible.

[andrebrito]

Rod, here it goes

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