[Den]

I'm guessing that they would absorb more acoustic energy if they were not 'lightweight.'

http://www.mioculture.com/store/pc/viewPrd.asp?idcategory=2&idproduct=9

[bpape]

Might work a little bit at some frequencies.   I don't like their description that it will eliminate standing waves - because it won't.  It might be interesting to try if it weren't $30 per square foot.


Bryan

[PhilNYC]

Might work a little bit at some frequencies.   I don't like their description that it will eliminate standing waves - because it won't.  It might be interesting to try if it weren't $30 per square foot.

It looks like $30 will get you 12 panels, not just one...

[Ethan Winer]

Den,

> I'm guessing that they would absorb more acoustic energy if they were not 'lightweight.' <

It looks to me like they're supposed to be diffusors. They might avoid standing waves - above 4 KHz.

--Ethan

[Scott F.]

Try
EggCartons.com
http://www.eggcartons.com/cat3_1.htm

For $19.60 you get 140 trays that measure 6 eggs by 5 eggs (I think thats a scientific unit of measure).

[bpape]

My bad.  Didn't see the 12 pack part.

It is an interesting pattern if you could fill the back with something to stiffen it up.

Bryan

[Rob Babcock]

They may not have much value as acoustic treatments but they look pretty cool.   They'd be pretty cheap as wall covering to add some accent.

[Russell Dawkins]

for the record - I visited a friend of a friend's "studio" a few years ago which was nothing more than a very tall double car garage - tall enough for an RV.

The entire thing (walls, doors and ceiling) was lined with egg cartons of the type linked to by Scott F. and I've got to say - it sounded pretty darn good!

I would never have guessed that the absorption would have been so even and have extended so low in frequency.

A room that would have otherwise sounded appalling, I imagine, actually sounded way more than just pleasant - I can imagine a good recording could have been made in there.

[jules]

Yes, I can confirm that it works!

I've tried a room with all walls and ceiling covered and the results are surprisingly good. Slightly tricky to attach 

Jules

[Rob Babcock]

I bet the WAF is pretty low!   Unless she grew up on a chicken farm!

I bet they're pretty flammable, too.

[jakepunk]

You better believe it's flammable.  Remember that fire in the Rhode Island nightclub a few years back?  It was the result of egg carton-like foam.

Investigators say the club was soundproofed with a polyurethane foam of the type used in egg-cartons, which is 20 times more flammable than wood and emits a thick, toxic smoke.

The fireworks ignited the foam, causing a fast moving fire that consumed the club within minutes.

The club's owners, Jeffrey and Michael Derderian, said they had no idea the foam was dangerous and fire inspections carried out at the club failed to spot the material covering the walls.

[Russell Dawkins]

I was thinking of the cardboard type egg trays which may be a little less flammable and would certainly produce less toxic smoke. I don't imagine the urethane foam type would be as effective, acoustically.

[jules]

WAF factor zero I'd imagine but when I did it I was a penniless student ... cool factor very high 

Definitely cardboard, as even without catching fire I don't think it would be all that great being exposed to that much surface area of possibly toxic [and smelly] plastic.

Fire factor ... probably a disaster either way 

Jules

[JohninCR]

I bet the WAF is pretty low!   Unless she grew up on a chicken farm!

As a ceiling treatment they actually look really nice as long as you attach them uniformly.  As Jules stated the trick is attaching them, and for the ceiling glue is required because they sag with humidity, so you need to attach them at all point of contact.

As a treatment, they function more as an absorber than a diffusor, and their shape makes them magnitudes more effective than a flat sheet of the same paper would be.  I get them free down here from my egg delivery and put them to acoustic use in a couple of ways. 

The first 8ft of my front ceiling slopes down toward my listening with major sonic problems.  I used them as as an absorptive layer that also added air space as part of my multi-layer "ceiling cloud" strategy.  I also wanted some moveable panel absorbers, so I started with some cheap plywood rectangles.  I glued the paper egg cartons to the plywood.  Then I covered that with 1" open cell foam rubber, wrapping the foam a couple of inches around the back before stapling in place.  Then I covered it with a thick stretchy fabric for asthetics.  Hung like pictures or leaned against the wall they work great.  Wrapping the foam around the back served 2 purposes.  The plywood won't rattle against the wall and I believe the somewhat sealed airspace makes them more effective in the bass region than just the mass of the plywood would dictate.  I ended up with 4 large effective and stylish absorbing panels for less than $40.  With MDF available for cheap (just not down here), you could build something similar and even more effective for bass due to the extra mass.

[Ethan Winer]

Russell,

> The entire thing (walls, doors and ceiling) was lined with egg cartons of the type linked to by Scott F. and I've got to say - it sounded pretty darn good! I would never have guessed that the absorption would have been so even and have extended so low in frequency. <

This is probably more of an "audio illusion" than a good way to treat a room. Egg cartons (and other thin materials) can do an acceptable job absorbing at speech frequencies. So when you talk in the room or clap your hands as a "test" the sound is indeed improved compared to the room when empty. The problem is thin materials absorb little below about 500 Hz, so the room is still boomy and bassy and still has peaks and deep nulls in the bass range.

--Ethan

[nathanm]

You mean you're not coming out with Real Traps EggTraps™, Ethan?

[Russell Dawkins]

Russell,
 The problem is thin materials absorb little below about 500 Hz, so the room is still boomy and bassy and still has peaks and deep nulls in the bass range.

--Ethan

Ethan,
the point of my post was that this was not the case, counter to apparent theory and expectations on my part.
I think one explanation could be that something was going on to allow some movement between the panels and the walls so they could function as membrane type bass traps.

That said, I am not saying it would necessarily measure perfect - it just sounded way better than it had a right to, and I am aware of the typical problem of skewed RT60 times resulting from more HF than LF absorption.

Russell

[Ethan Winer]

Russell,

> the point of my post was that this was not the case, counter to apparent theory and expectations on my part. <

And I hope I didn't come off as combative.

The only way to really know what changed after adding egg cartons is to measure using ETF or equivalent. I wouldn't be surprised if there were some "membrane" behavior going on. But unless the egg cartons were damped, any low-midrange absorption is probably pretty narrow. And not likely to extend to the bass range.

--Ethan

[nathanm]

I've found that putting real chicken eggs into the compartments helps with diffusive properties but not as much as stapling the fully grown chickens to the wall.  The clucking can be a nuisance but you simply increase the program level to compensate.  A chicken wire cylinder stuffed with roosters makes an excellent bass trap as well.

[JohninCR]

I wouldn't be surprised if there were some "membrane" behavior going on. But unless the egg cartons were damped, any low-midrange absorption is probably pretty narrow. And not likely to extend to the bass range.
--Ethan

Ethan,
It makes sense that their effect wouldn't be much in the bass range, except to damp and lower the resonant frequency of whatever panel they are mounted on, and obivously measuring is needed to know.  I'm surprised though that this isn't already known, because they are quite effective over a broad range of frequencies due to their contour and material.

I don't know what you meant about needing to be damped.  We're not talking about the foam egg cartons, which would be all but useless.  These seem like a raw paper pulp pressed into a thick egg carton form and are nowhere near as resonant as cardboard, and I believe they belong near the top of any DIY list for taming a bright room.