Styrofoam Diffusors?

[spoonie g]

Polystyrene, more specifically I guess, but anyways... Do these work?

[Glenn Kuras]

Originally Posted by spoonie g

Polystyrene, more specifically I guess, but anyways... Do these work?

yes it will work, but it may absorb some also. Truly you would need to test its scattering effect and absorption effect in a lab to make sure.. But RPG I believe makes a diffusor this way also. Not sure of the density though.

Glenn

[mahasandi]

RPG uses a high density extruded polystrene
which can be bought at home depot
in the insulation section just check theyre description.
and no; its not absorbtive if it is high
density.
Its just very time intensive
but worth it if you enjoy making stuff.

[joeq]

styrofoam is highly flammable, and when it burns it emits some really toxic gases.

[Kiwiburger]

I can see the appeal of styrofoam to manufacturers - because it's dirt cheap, and extremely light. You can make some serious eye candy with styrofoam. Architectural acoustic design has a high element of cosmetics and smoke and mirrors and marketing puffery.

You could market a very fancy looking diffuser with low shipping costs, designed to baffle customers with bullshit.

But it's an absolute crap acoustic material. And a fire hazard. And it tends to have a resonant frequency within the audio range (try pinging it with your finger). The stuff can squeak if you aren't careful how you mount it.

Avoid.

[Glenn Kuras]

Originally Posted by Kiwiburger

I can see the appeal of styrofoam to manufacturers - because it's dirt cheap, and extremely light. You can make some serious eye candy with styrofoam. Architectural acoustic design has a high element of cosmetics and smoke and mirrors and marketing puffery.

You could market a very fancy looking diffuser with low shipping costs, designed to baffle customers with bullshit.

But it's an absolute crap acoustic material. And a fire hazard. And it tends to have a resonant frequency within the audio range (try pinging it with your finger). The stuff can squeak if you aren't careful how you mount it.

Avoid.

We looked at doing our D1 Diffusor this way to lower the price for people, but backed out in fear of people getting them and then posting we just sold them a piece of Styrofoam. In fact we had a few made and people thought they where something for a packing box.
I think RPG must have a cool way of making them (I have never seen one) because no one seems to care. Like mahasandi pointed out they must be very dense or something.

Glenn

[nosebleedaudio]

I have seen the RPG styrofoam diffusors, and I dont think they are worth it.
If placed where people walk and can be hit it's VERY easy to snap off a section. And it can not be fixed, you can't glue that stuff, I've tried...
I'll take a hard wood anyday...
My .02cents

[spoonie g]

but the question is: do they work?

[nosebleedaudio]

Originally Posted by spoonie g

but the question is: do they work?

Yes...

[spoonie g]

Originally Posted by nosebleedaudio

Yes...

So, theyre worth it if theyre not where people walk in your opinion?

[espen askelad]

I can't imagine it'd pass the fire inspection codes.

[nosebleedaudio]

Originally Posted by espen askelad

I can't imagine it'd pass the fire inspection codes.

On the ceiling is a good place, and it's hard to imagine a large company producing a product that will not pass code.

[Andreas G]

Originally Posted by Kiwiburger

But it's an absolute crap acoustic material. And a fire hazard. And it tends to have a resonant frequency within the audio range (try pinging it with your finger). The stuff can squeak if you aren't careful how you mount it.

Avoid.

Seems like you have had very bad experiences? Which one did you use? I use the RPG-Skyline diffusors in the back of my room, to me they sound excellent! The flame retardant grades meets the requirements of FMVSS-302 standards regarding to RPG.

Andreas

[egan]

Originally Posted by nosebleedaudio

...and it's hard to imagine a large company producing a product that will not pass code.

Right...it's also sold as a wall insulation/moisture barrier. I don't think OC and Dow would/could have a popular product on the market that doesn't meet fire code. It may look the same, but it probably isn't the same stuff they make beer coolers out of.

[nosebleedaudio]

Originally Posted by egan

Right...it's also sold as a wall insulation/moisture barrier. I don't think OC and Dow would/could have a popular product on the market that doesn't meet fire code. It may look the same, but it probably isn't the same stuff they make beer coolers out of.

It depends on where and how a material is used, for example regular wood is NOT allowed in some buildings IF not covered with a class A material.
Had this on a recent studio I design/built in a class 4 building.
Depends on exposure...

[Jidis]

I did a styrofoam diffusor a few years back. As mentioned, it is somewhat fragile. Mine went in a fairly "safe" location, where it was behind a workstation, so you couldn't get too close to it. I also painted the face of it with a mixture of primer and wood glue to harden it. There are probably resins and stuff you could also use, just make sure you don't try anything that eats the styro.

As much as styrofoam might suck, be aware that you're dealing with a pretty substantial amount of "board feet" of material to get any decent well depth and wall coverage. I intended to use something more solid until I realized that just that one box (4 or 5 feet) ended up being like a couple full sheets of material or something (very heavy if not styro).

Good Luck,

George

PS- You a Spoonie G fan?

[spoonie g]

Originally Posted by Jidis

I did a styrofoam diffusor a few years back. As mentioned, it is somewhat fragile. Mine went in a fairly "safe" location, where it was behind a workstation, so you couldn't get too close to it. I also painted the face of it with a mixture of primer and wood glue to harden it. There are probably resins and stuff you could also use, just make sure you don't try anything that eats the styro.

As much as styrofoam might suck, be aware that you're dealing with a pretty substantial amount of "board feet" of material to get any decent well depth and wall coverage. I intended to use something more solid until I realized that just that one box (4 or 5 feet) ended up being like a couple full sheets of material or something (very heavy if not styro).

Good Luck,

George

PS- You a Spoonie G fan?

Man, if that were behind me, it'd be destroyed in less than a week. Spoonie G is ok. I mainly like how it sounds.

[DSD_Mastering]

Here are some my friend made. He used the RPG as his template and also has them on the front half of his ceiling.

Regards,
Bruce

[Old Goat]

Very cool!

I worked for Dow years ago. Real Styrofoam™ won't burn. There's a really nasty, toxic, antievolutionary fire retardent in it. Exposure to it makes you have naked babies. Didn't affect me, though...me, though...me, though.

[Jidis]

Yeah, most of the sheet stuff is made for underlayment in siding and construction. I'd figure they'd have to comply with most codes somehow.

BTW- I used to work in a building supply warehouse that sold some nice stuff by Amoco that went under siding. The regular "Amocor" was too puffy and layered, but there was a green one that looked perfect ("Amofoam" maybe). It was stiff and came in bundles of 2'x8' panels or something. Cut really easy too. Not sure if it's still around though.

George

[nosebleedaudio]

I built one a few years ago out of Poplar, believe it weighed around 40 pounds for a 2' by 2'.
I would put one on a wall, but on a ceiling would be questionable.
I also made mine far deeper than the RPG, distance changes things...

[Jidis]

I'd like to see someone DIY one of the "hollow body" types. That would seem to solve the weight issue. I had considered doing one of Plexiglas to cover a window on my rear wall, but I chickened out.

I forgot to mention, the blue labeled Liquid Nails (for projects and foamboard) was used to glue the individual slats of that styrofoam diffusor. It's lighter and softer than the regular one, and made a really tight bond, so I guess it would also work for repair, should you break any styrofoam. I had also considered facing the box with some sort of grill for protection, but I don't know what that would do to its acoustical function.

George