Warsound

[Image: U.S. helicopter over Baghdad, via (scroll down)].

I’ve mentioned The Forever War by Dexter Filkins before, but I was struck again the other day by a passage in which Filkins catalogs the mechanically unprecedented sounds of the American siege of Falluja, a collection of noises so alien and overpowering that he describes it as “an entire ecosystem” with its own hidden predators and prey.

Filkins writes that “rocket-propelled grenades whizzed out of the darkness, striking the M-1s and exploding but doing no harm. Whoosh-bang, like a fireworks show. Whoosh-bang.” He quickly adds, however, that “the real weirdness was circling above.”

The night sky echoed with pops and pings, the invisible sounds of frantic action. Most were being made by the AC-130 gunships, whose propellers were putting out a reassuring hum. But over the droning came stranger sounds: the plane’s Gatling gun let out long, deep burps at volumes that were symphonic. Its 105mm cannon made a popping sound, the same as you would hear from a machine that served tennis balls. A pop! followed by a boom! Pop-boom. And then there was the insect buzz of the ScanEagle, the pilotless airplane that hovered above us and beamed images back to base. It was as if we were witnessing the violent struggles of an entire ecosystem, a clash of airborne nocturnal beasts we could not see.

Of course, the unnatural acoustic ecology of humans at war is surely something you could find throughout history, from the fibrous zing of crossbow strings and the thunderous lurch of the catapult to endlessly irritating scrapings of metal on metal as swords and shields collide. What ancient Roman warfare actually sounded like is something for the acoustic archaeologists.

But, while an acoustic history of war has yet to be written—though some have treated sound itself as war—it would be a fascinating study to pursue.

Sonic Warfare

The opening scene of The Forever War by Dexter Filkins presents us with the sight of U.S. soldiers preparing for their invasion of Falluja. Filkins is there to witness the attack; amidst the growl of tanks and Humvees, and “by the light of airstrikes and rockets,” he writes, there is suddenly something sonically unexpected.


[Image: “An Advanced Individual Training Soldier in the Psychological Operations Specialist Course attaches a loud speaker on top of a High Mobility Multi-Wheeled Vehicle, or HUMVEE, at Forward Operating Base Freedom, Camp MacKall, N.C.” Courtesy of the John F. Kennedy Special Warfare Center and School].

“And then, as if from the depths,” Filkins writes, “came a new sound: violent, menacing and dire.”

I looked back over my shoulder to where we had come from, into the vacant field at Falluja’s northern edge. A group of marines were standing at the foot of a gigantic loudspeaker, the kind used at rock concerts.

It was AC/DC, the Australian heavy metal band, pouring out its unbridled sounds. I recognized the song immediately: “Hells Bells,” the band’s celebration of satanic power, had come to us on the battlefield.

While by no means advocating the use of sonic warfare as a tool in U.S. military adventures or police operations, I nonetheless instantly thought of this scene—of armed soldiers holding aloft rock-blaring boom boxes, like some John Milius-directed remake of Say Anything—when I read, in a very different context, that bark beetles can be driven out of the pine forests they currently infest if you play digitally-altered sounds of their own chewing back at them through loud speakers. The high-volume sound of themselves drives them away.

A research assistant suggested using sounds to aggravate the beetles, much as police sometimes blare music in hostage situations. The researchers tried Queen and Guns N’ Roses and played snippets of radio talker Rush Limbaugh backward. None produced the desired results.

Then, the beetles were exposed to digitally altered recordings of their own calls, the sounds they make to attract or repel other beetles. The response was immediate. The beetles stopped mating or burrowing. Some fled, helter-skelter. Some violently attacked each other.

Most important, they stopped chewing away at the pine tree, suggesting that the scientists may have discovered a sort of sonic bullet that could help slow the beetles’ destructive march.

Again, I do not mean to imply that infestation metaphors are the most appropriate to use when discussing Operation Phantom Fury, or that military action in that city was analogous to clearing a forest of bark beetles; but the audio possibilities here, and the specifics of the set-up, seem amazing.


[Image: A ponderosa pine forest; within those trunks might be beetles].

More about the actual experiment, run at Northern Arizona University’s Forestry Lab:

They collected tree trunks infested with bark beetles… Working in the lab, [research assistant Reagan McGuire] piped in the music through tiny speakers, the sort you might find in a singing greeting card. He watched the reaction of the beetles using a microscope. The rock music didn’t seem to annoy the bugs, nor did Rush in reverse.

McGuire and [Northern Arizona University forest entomologist Richard Hofstetter] decided to try something different. They recorded the sounds of the beetles and played them back, manipulating them to test the response.

Suddenly, every little thing they did seemed to provoke the beetles.

“We could use a particular aggression call that would make the beetles move away from the sound as if they were avoiding another beetle,” Hofstetter said.

When they made the beetle sounds louder and stronger than a typical male mating call, he said, the female beetle rejected the male and moved toward the electronic sound.

These audio simulations, in other words, had demonstrable physical effects on another species; their own warped sonic portrait drove them crazy.

So could you reprogram your Marsona 1288A (“create a personalized sound environment“) with the digitally-altered ambient sounds of termites and thus clear your house of insectile pests? The USDA, after all, has published a paper—download the PDF—explaining how a “portable, low-frequency acoustic system was used to detect termite infestations in urban trees.” Indeed, “termite sounds could be detected easily underneath infested trees, despite the presence of high urban background noise.” So why not reverse this—drive them out of the city using weird MP3s specially produced for boom cars?

Perhaps we should petition Clear Channel or Sirius XM to premiere a new, insect-only broadcast hour, killing ants and roaches in every city where it’s played (or perhaps just driving them all out, streaming from the floorboards, in a moment of utter horror).

I’m reminded here of the famous example of Sgt. Pepper’s Lonely Hearts Club Band by The Beatles, with its “dog whistle—which humans can’t hear—buried on the album’s second side.” Only, in our case, it would be a different kind of beetle-whistle, and one with anti-infestational effects.

(Bark beetle story found via @treestrategist).

The exact acoustic shape of
the skies above Los Angeles

[Image: Photo by John Gay: an F/A-18 creates a condensation cone as it breaks the speed of sound].

An email was sent out last week from the Regional Public & Private Infrastructure Collaboration Systems (RPPICS) – an organization with no apparent web presence – warning many businesses in and around Los Angeles that city residents “could hear up to a dozen sonic booms this morning [June 11] as some NASA F/A-18 aircraft fly at supersonic speeds around Edwards Air Force Base.”

While the “loudness of the booms will vary,” we read, these are only “preliminary calibration flights for an upcoming NASA study” that will research how “to reduce the intensity of sonic booms.” Part of this will be studying “local atmospheric conditions,” including air pressure, wind speed, and humidity, as these all entail acoustic side-effects.

It’s a sonic cartography of the lower atmosphere: an echo-location exercise. The geometry of noise.

Sound-bombing L.A. from above in order to know the exact acoustic shape and structure of the sky.

Dolby Earth / Tectonic Surround-Sound

“In any given instant,” the Discovery Channel reminds us, “one or more rocky plates beneath Earth’s surface are in motion, and now visitors to a California museum exhibit can hear virtually every big and small earthquake simultaneously in just a few seconds off real time. Scientists have captured earthquake noises before, but this is believed to be the first instantaneous, unified recording of multiple global tectonic events, and it sounds like the constant, dull roar of the world’s biggest earthquake chorus.”

The planet, droning like a bell in space.

Of course, the musicalization of the earth’s tectonic plates has come up on BLDGBLOG before, specifically in the context of 9/11 and the collapse of the Twin Towers. Among many other things, 9/11 was an architectural event which shook the bedrock of Manhattan; the resulting vibrations were turned into a piece of abstract music by composer Mark Bain (more info at the Guardian – and you can listen to an excerpt here).

Meanwhile, if somebody set up a radio station – perhaps called Dolby Earth – permanently dedicated to realtime platecasts of the earth’s droning motions… at the very least I’d be a dedicated listener. A glimpse of what could have been: Earth: The Peel Sessions.

In any case, if I could also remind everyone here of an interview with David Ulin, in which he discusses the intellectual and philosophical perils of earthquake prediction – the topic of his excellent book, The Myth of Solid Ground. One of the predictors discussed in Ulin’s book, for instance, spends his time “monitoring a symphony of static coming from an elaborate array of radios tuned between stations at the low end of the dial.”

Dolby Earth, indeed.

(Thanks to Alex P. for the Discovery Channel link! Related: Sound Dunes).

Sound dunes

“Sand dunes in certain parts of the world are notorious for the noises they make,” New Scientist reports, “as sand avalanches down their sides. Some [dunes] emit low powerful booms, others sound like drum rolls or galloping horses, and some are even tuneful. These dune songs have been reported to last for up to 15 minutes and can sound as loud as a low-flying airplane.”

To test for the causes, properties, and other effects of these sand dune booms, “Stéphane Douady of the French national research agency CNRS and his colleagues shipped sand from Moroccan singing dunes back to his lab to investigate.” There, Douady’s team “found that they could play notes by pushing the sand by hand, or with a metal handle.”

The transformation of a sand dune – and, by extension, the entire Sahara desert, indeed any desert – even, by extension, the rust deserts of Mars – into a musical instrument. Music of the spheres, indeed.

“When the sand avalanches, the grains jostle each other at different frequencies, setting up standing waves in the cascading layer, says Douady. These waves reinforce one another, making the layer vibrate like the surface of a loud speaker. ‘What’s funny is that in these massive dunes, only a thin layer of 2 or 3 centimetres is needed to set up the resonance,’ says Douady. ‘Soon all grains begin to vibrate in step.'”

Douady has so perfected his technique of dune resonance that he has now “successfully predicted the notes emitted by dunes in Morocco, Chile and the US simply by measuring the size of the grains they contain.” The music of the dunes, in other words, was determined entirely by the size, shape, and roughness of the sand grains involved, where excessive smoothness dampened the dunes’ sound.

I’m reminded of the coast of Inishowen, a peninsula south of Malin Head in the north of Ireland, where the rocks endlessly grind across one another in the backwash of heaving, metallic, grey Atlantic waves. Under constant pressure of the oceanic, the rocks carve into themselves and each other, chipping down over decades into perfectly polished and rounded spheres, columns, and eggs – as if Archimedean solids or the nested orbits of Kepler could be discovered on the Irish ocean foreshore –

– all glittering. The rocks, I later learned, were actually semi-precious stones, and I had a kind of weird epiphany, standing there above the hush and clatter of bejewelled rocks, rubbing and rubbed one to the other in the depopulated void of a coastal November. It was not a sound easy to forget.

Because the earth itself is already a musical instrument: there is “a deep, low-frequency rumble that is present in the ground even when there are no earthquakes happening. Dubbed the ‘Earth’s hum‘, the signal had gone unnoticed in previous studies because it looked like noise in the data.”

Elsewhere: “Competing with the natural emissions from stars and other celestial objects, our Earth sings like a canary – it drones on in a constant hum of a gazillion notes. If it were several octaves higher, and hence, audible to the human ear,” it could probably get recorded by the unpredictably omnidirectional antennas of ShortWaveMusic and… you could download the sound of the earth. Free Radio Interterrestrial. [Note: the “drones on” link, a sentence or two back, offers a contrary theory (published in 2000) about the origins of these planetary sound waves.]

Which, finally, brings us to Ernst Chladni and his Chladni figures, or: architectonic structures appearing in sand due to patterns of acoustic resonance. The architecture of sand, involving sound—or architecture through sound, involving sand. Silicon assuming structure, humming.

The gist of Chladni’s experiments involved spreading a thin layer of sand across a vibrating plate, changing the frequency at which the plate vibrated, and then watching the sand as it shivered round, forming regular, highly geometric patterns. Those patterns depended upon, and were formed in response to, whatever vibration frequency it was that Chladni chose.

So you’ve got sand, dune music, terrestrial vibration, some Chladni figures – one could be excused for wondering whether the earth, apparently a kind of carbon-ironic bell made of continental plates and oceanic resonators, is really a vast Chladni plate, vibrating every little mineral, every pebble, every grain of sand, perhaps every organic molecule, into complex, three-dimensional, time-persistent patterns for which we have no standard or even technique of measurement. Or maybe William Blake knew how to do it, or Pythagoras, or perhaps even Nikola Tesla, but…

The sound dunes continue to boom and shiver. The deserts roar. The continents hum.