Papercreters: [papercreters] Sound Chamber Recipe Guess -was- Re: papercreters

Thursday, July 17, 2008

[papercreters] Sound Chamber Recipe Guess -was- Re: papercreters

Hello Larry,

Welcome to the group. Excellent first post. Keep 'em coming.

It sounds like you are describing an "anechoic" chamber.
http://www.ee.washington.edu/about/centennial/looking_back/historical-
JPEGs/anechoic-chamber.jpg
Yahoo will probably chop up that long link, so here's the same link
again as a tiny clickable URL.
http://tinyurl.com/6e2nne

The big issue to be considered is where are the noise sources?

If noise is occuring inside the room, conic shapes inside the room
will help breakup the audio waves as they strike the walls.

If the noise is occuring outside the room, conic shapes inside the
room will not help very much.

A better strategy for noise coming from outside the room is a
reflective barrier on the outside of a sound absorbing layer
(papercrete). A hard surface will reflect most of the outside sound
before it even encounters the papercrete absorption layer.

Most of us have encountered a hallway with a hard floor and
cinderblock walls. It echos sound really well because of the hard
surfaces.

A room with carpet, curtains, and overstuffed furniture rarely echos.

Some high performance recording studios will have an anechoic (non-
echo-producing) chambers so that background sounds will be
minimized. These sounds might be the sounds of music pages getting
turned, or the trumpet player tapping his foot to keep the beat.

In research envoronments, anechoic chambers can be used to record
pure sounds coming from equipment. For example, careful analysis of
an electric motor's sound might reveal a bad bearing long before it
fails. Echos off the walls can confuse such sensitive recording and
analysis equipment.

A dishwashing machine manufacture may run tests inside anechoic
chambers to measure exactly how much noise prototypes of new models
produce to see if they are quieter than last year's models.

You are correct that the conical shapes can be helpful in baffling
whatever sounds are inside a room, regardless of how they got there.

I guess it all boils down to how quiet do things need to be? What is
someone trying to accomplish?

If the goal is to create a quiet room for meditation, (the purpose
someone posted at one time recently) there shouldn't be much noise
inside the chamber to be baffled to begin with. Resources would be
better spent going with a thicker papercrete layer to absorb noise
before it gets inside, or a hard surface reflective layer to bounce
outside noise away.

If the goal is to keep any inside sounds from echoing around, then
the conical shapes are very very useful.

That's my understanding.

Maybe others have better insights than I do.

--- In papercreters@yahoogroups.com, larystoy@... wrote:
>
>
> I'm not exactly sure, but I remember reading an article a few years
back about using egg cartons for sound proofing. It seems the shape
of the carton somehow deflects sound.
> I have seen rooms with panels arranged sticking out from the walls
to adsorb sound.
>
> OK, what does this have to do with Papercreate?
>
> Depending on how big an area (room) you want to sound proof, it
seems that if you used the egg shell shape and made your Papercreate
form in that shape it should work.
>
> Probably want to make the cones about 6" in diameter and 3" or 4"
deep. Seems like it could be done without too much of a problem.
>
> Question is how to validate it and could the forms be made that
way? I would think you could pour your blocks as you normally would,
and just before it sets up, have some sort of coned form that you
could just press into the Papercreate to create the indentations with.
>
> Anyone with other ideas? This should open the door for some lively
further discussion.
>
> PS:
>
> I have been lurking in the background and reading each article on
Papercreate avidly each day, sure is a lot of good and interesting
information available when people share their ideas and mistakes.
>
> Problem is I have been busy building a HPV (Human Powered Vehicle)
the past few weeks. But one of my projects I want to complete this
summer is my 55 gallon Papercreate mixer.
>
> I will be documenting how I make it and posting a page on my
website showing all of the details, fun, mistakes and such when I
start that project.
>
> For those that would like to see the HPV article the URL is
www.websbylarry..com.
>
>
> Larry Arnold
> larystoy@...
>
>