Science: ancient soundscapes

Lanzon Gallery at Chavin, Physics Today

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This headline, "Uncanny acoustics at a Peruvian archaeological site," at AIP's Physics Today caught my attention because it's unusual to hear a scientist use the word uncanny.

According to Encyclopedia Brittanica architectural acoustics is known to have been studied and applied for 2000 years. Miriam Kolar's research as part of the Chavín de Huántar Archaeological Acoustics Project has pushed the knowledge envelope back a thousand years. Similar research has been done at Stonehenge. In fact you can purchase apps for Apple and Android in which reproduce conditions there.

Below is a video illustrating the sound dynamics of Stonehenge, posted by Rupert Till.

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Returning to the Peruvian archaeological site, Kolar describes the effects of the chamber:

Present-day pututu musicians playing in the narrow, stone-lined corridors, alcoves, and rooms of Chavín have reported sensing their instruments “pulled into tune,” almost as if an unseen presence were guiding their playing. If two musicians blow on their shell horns close together, they may sense their instruments coming into sync with each other. What could account for that seeming phantom force?

While playing a shell horn, a musician’s lips vibrate in sync with the oscillations of the air in the shell’s spiraled interior. A player can modify the instrument’s tone by increasing the frequency of his or her lip vibrations, changing the shape of the air column inside the instrument by inserting a hand in the shell’s opening, or changing the shape of the vocal tracts. Those actions are all intuitive performance techniques.

Kolar explained that the small, enclosed spaces inside Chavín’s massive stone buildings have strong naturally occurring resonance frequencies, which can couple with the resonance of the pututu and the musician’s own lips and vocal tract. The acoustic coupling guides the musician and the instrument into a matching sound with the room. Both musician and listeners sense the eerie effect.

This is an ancient pututu. Note that it's modelled after a large conch shell.

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Chavin pututus, Stanford Chavín de Huántar project

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Acoustic couplers like the one below were used in the early days of using modems to connect to a network. And resonance is a powerful effect, known to bring down bridges.

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Acoustic Coupler, Wikimedia

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--Marge

DIY: traveling where the Sun is brutal

It sure is good to have warm, sunny days again after this horrific winter.  Road trip!

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John Cook, I-80 west of Elko, Wikimedia

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Before you venture out, it's best to prepare--especially if your path includes a desert.  If hiking, here are some tips from WikiHow.

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Sydney dust storm, WikiHow

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If you're just traversing desert-like terrain to get somewhere else, here are some survival tips in case your vehicle decides to stop and refuses to go again.

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Desert sun, Discovery News

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To get an idea of how brutal the sun can be, here's an article on sun-poisoning.

If you'd like to get a taste of what it's like to be in the desert in summer, best to join a hiking club.

-- Marge

Out fishin' again

Gone fishin' today...

In the meantime, here for your viewing pleasure is Wikimedia Commons "Picture of the Year 2013."  The other entries are eye-catching, too.

Stefan Krause, Germany (License: FAL 1.3).

 

-- Marge

Art: scratchboarding

At Michael's the other day, looking for matte board, I came across a scratchboard.  Not familiar with the technique, I began looking around online for information on what tools to use, the range of effects to expect, and general techniques.  I was amazed.  Finished scratchboard pieces remind me of lithographs, without the need for expensive lithograph stones and even more expensive press (although you can grind out many prints with this method).  Attending art classes at the local university is probably the only way an ordinary person can learn and do printmaking.

Here's an example of a lithograph, this one by J. Pilizotti, after a sketch by Albrecht Dürer of Saint Jerome in his study. Master engraver Dürer himself worked with metal plates, usually copper.
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Lithograph by J. Pilozotti, Wikimedia

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Now, back to scratchboard.   This piece was found at the ISSA (International Society of Scratchboard Artists) Master Members Gallery:
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Patrick Hedges, "Cheetah," ISSA

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Artist Russ McMullin sponsors Scratchboard.org, where I found these two pieces:
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Lorrie Dunn, "CanineAncestry," scratchboard.org

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Nico Delort, untitled, scratchboard.org

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Artist McMullin's own work is masterful and can be found at his site/blog.  Here's his portrait of Ralph:
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Russ McMullin, portrait of Ralph

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You can add color to a scratchboard piece, as shown below, but I love the inky blacks, contrasts, and textures.
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Sandra Willard, "Bowl of Cherries," ISSA

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-- Marge