[Aztlan] Raindrop effect at all Mesoamerican pyramids?

[Wayne Van Kirk]

#1) "sound result of evanescent waves related to the corrugations."
VS

#2) "two-dimendional drum model. According to the simpler model, the
raindrop effect is essentially a drum sound that would be expected on
"hollow" pyramids such as
 the temple of Kukulkan"

Not that I know what I'm talking about but couldn't this be resolved by a simple experiment? 

Create an impulse sound that does not require physical contact with the steps .Perhaps a handclap, placed close to
the steps.  If # 1 is correct we would expect a good raindrop effect on the opposite end, if #2 is correct we would expect no much at the opposite end.
Or some of both?

WVK











--- On Sun, 10/4/09, Marcelo Donadello <marcemusic at yahoo.com> wrote:

From: Marcelo Donadello <marcemusic at yahoo.com>
Subject: Re: [Aztlan] Raindrop effect at all Mesoamerican pyramids?
To: aztlan at lists.famsi.org
Date:
 Sunday, October 4, 2009, 8:07 PM

Listeros:

First, the sound reflection in mid and high frequencies does not have relation with the quota of
 flexibility (membrane like?? !!) that would generate sounds of
 rain or of quetzal, any vibration
 associated with the mentioned magnitudes (interior mass of the pyramid) would have much lower frequency.

And it is impossible that a tunnel (a relatively small hole in the total mass of the pyramid) influences perceptibly in the external echoes of this one.

It makes no physical seriousness what is being proposed. Mid and high frequency reflections only have relation with the exterior form and the covering of the pyramids. Sorry.

Forgive my english.
My today -2 cents.
Marcelo Donadello, músico.



--- El sáb 3-oct-09, David Lubman <dlubman at verizon.net> escribió:

> De: David Lubman <dlubman at verizon.net>
> Asunto: [Aztlan] Raindrop effect at all Mesoamerican pyramids?
> Para: aztlan at lists.famsi.org
> Fecha: sábado, 3 de octubre de 2009, 5:24 pm
> Listeros:
>
> David Hixson posted this item on
 9/29/09 and repeated
> below:
>
> Wayne Van Kirk wished me to forward this recent news
> article to the list...
>
> "Mayans 'played' pyramids to make music for rain god"
>
> http://www.newscientist.com/article/mg20327266.200-mayans-played-pyramids-to-make-music-for-rain-god.html?DCMP=OTC-rss&nsref=online-news
>
> This 22 September New Scientist article was written by
> Linda Geddes. There were 40 reader comments at the NS
> website at last check. It is based on a paper
 recently
> published in Acta Acustica united with Acustica, DOI:
> 10.3813/AAA.918216
>
> The article provides a great opportunity to add some
> archaeology to archaeological acoustics. Mesoamerican
> experts have the best resources and understanding to answer
> questions raised in this paper. I will attempt to describe
> it's acoustical thesis neutrally, withholding my own
> opinions.
>
> The article is one of several papers by the authors about
> the "raindrop effect", so named by the second author
> (Declercq) who discovered it at the temple of Kukulkan at
> Chichen Itza in 2002. The effect is said to resemble the
> sound of a raindrop falling into a bucket. The sound is
> stimulated by footfalls on the staircase, and is heard only
> very close to the surface of the staircase.
>
> A key question: Is the"raindrop effect" a feature of
 all
> Maya pyramids and all Mexican pyramids as its authors claim?
> (Perhaps the authors meant all staircased limestone
> pyramids.)
>
> The authors explain the sound as result of evanescent waves
> related to the corrugations.
>
> One critic suggested a explanation based on a simpler
> heuristic, two-dimendional drum model. According to the
> simpler model, the raindrop effect is essentially a drum
> sound that would be expected on "hollow" pyramids such as
> the temple of Kukulkan, but not on filled or "solid"
> pyramids (those with airspaces beneath their staircase.) The
> simpler heuristic model envisions the staircase as a more or
> less homogeneous rectangular elastic membrane fixed at its
> four boundaries (two balustrades and at the top and bottom
> of the staircase) but free to flex when stimulated by
> footfalls in mid-staircase.
 Obviously, the staircase could
> not drum if there was no airspace underneath. He offered
> anecdotal evidence of an uynidentified pyramid (possibly at
> Copan) at which the raindrop sound was absent until an
> archaeologists tunnel was dug into it.
>
> A simple one dimensional reduction would be a violin string
> or better, an elastic rod, held taught at both ends
>
> Ths subject paper responds to the unstated criticism with
> new tests at Teotihuacán's pyramid of the moon which
> demonstrated the existence of the raindrop effect on a solid
> (no airspace) pyramid (?) The authors offer this as proof
> that the raindrop effect exists on all pyramids.
>
> Mesoamericanists, please comment!
>
> David Lubman
> -------------------
>
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