Take a peek inside a flickering candle flame with these 3D-printed shapes

New research from MIT explores fire from a whole series of new perspectives. The research uses deep-learning approaches that extract the vibrational features of flames as flickering objects and, in turn, renders them into sounds and materials.

The 19th-century physicist Michael Faraday was known not only for his seminal experimental contributions to electromagnetism but also for his public speaking. His annual Christmas lectures at the Royal Institution evolved into a holiday tradition that continues today. One of his most famous Christmas lectures concerned the chemical history of a candle. Faraday illustrated his points with a simple experiment: He placed a candle inside a lampglass in order to block out any breezes and achieve “a quiet flame.” Faraday then showed how the flame’s shape flickered and changed in response to perturbations.

“You must not imagine, because you see these tongues all at once, that the flame is of this particular shape,” Faraday observed. “A flame of that shape is never so at any one time. Never is a body of flame, like that which you just saw rising from the ball, of the shape it appears to you. It consists of a multitude of different shapes, succeeding each other so fast that the eye is only able to take cognizance of them all at once.”

Now, MIT researchers have brought Faraday’s simple experiment into the 21st century. Markus Buehler and his postdoc, Mario Milazzo, combined high-resolution imaging with deep machine learning to sonify a single candle flame. They then used that single flame as a basic building block, creating “music” out of its flickering dynamics and designing novel structures that could be 3D-printed into physical objects. Buehler described this and other related work at the American Physical Society meeting last week in Chicago.

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#acoustics, #biomaterials, #biomimicry, #candle-flame, #fire, #gaming-culture, #machine-learning, #materials-science, #science

Jennie C. Jones, a Minimalist Who Calls Her Own Tune

In paintings, drawings, sculpture and sound art, she explores the relationship between hearing and seeing.

#acoustics, #art, #content-type-personal-profile, #guggenheim-solomon-r-museum, #jones-jennie-c, #music

Physicists captured, quantified the sound of champagne’s effervescence

The physics behind champagne's bubbly delights is surprisingly complex—including the source of its distinctive crackling sound.

Enlarge / The physics behind champagne’s bubbly delights is surprisingly complex—including the source of its distinctive crackling sound. (credit: Jon Bucklel/EMPICS/PA/Getty Images)

There’s rarely time to write about every cool science-y story that comes our way. So this year, we’re once again running a special Twelve Days of Christmas series of posts, highlighting one science story that fell through the cracks in 2020, each day from December 25 through January 5. Today: Researchers have uncovered the specific physical mechanism that links champagne’s distinctive crackle with the bursting of its tiny bubbles.

There’s nothing quite like the distinctive crackling and fizzing sound of a glass of freshly served champagne. It’s well established that the bursting of the bubbles produces that sound, but the specific physical mechanism isn’t quite clear. So physicists from Sorbonne University in Paris, France, decided to investigate the link between the fluid dynamics of the bursting bubbles and the crackly fizzy sounds. They described their work in a paper published back in January in the journal Physical Review Fluids.

As we’ve reported previously, the first mention of a sparkling wine dates back to 1535 in the Languedoc region of France. The classic brand Dom Perignon gets its name from a 17th-century monk who had the job of getting rid of the bubbles that developed in his abbey’s bottled wine, lest the pressure build up so much they exploded. Legend has it that upon sipping such a bubbly wine, the monk realized the bubbles might not be such a bad thing after all, declaring, “Come quickly, brothers, I am drinking stars!”

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#12-days-of-christmas, #acoustics, #bubbles, #effervescence, #fluid-dynamics, #food-science, #hydrodynamics, #physics, #science

From a Burger King to a Concert Hall, With Help From Frank Gehry

The Los Angeles Philharmonic’s ambitious new home for its youth orchestra is the latest sign of the changing fortunes of Inglewood.

#acoustics, #architecture, #beckmen-judith-and-thomas-l-yola-center, #california, #classical-music, #disney-walt-concert-hall, #dudamel-gustavo, #el-sistema, #gehry-frank, #inglewood-calif, #los-angeles-calif, #los-angeles-philharmonic, #restoration-and-renovation, #smith-chad-music-executive, #stadiums-and-arenas

Focusing sound vibrations precisely can knock over one Lego minifig among many

Brian Anderson's experiments with Lego minifigs led to the development of an interactive museum exhibit in Switzerland.

Enlarge / Brian Anderson’s experiments with Lego minifigs led to the development of an interactive museum exhibit in Switzerland. (credit: Brian Anderson)

Legos are a beloved staple of educational science activities and have even proved useful in particle physics experiments at CERN to explore the properties of hadrons. For Brian Anderson, a physicist at Brigham Young University, Legos are an essential component of his acoustics research. At a meeting of the Acoustical Society of America in Seattle earlier this month, Anderson described how he figured out how to focus sound-wave energy precisely enough to knock over a single Lego minifig without disturbing other minifigs clustered around it.

The key is a signal-processing technique called “time reversal,” originally used by submarines in the 1960s to help focus signal transmission in the ocean. The name is a bit misleading, since it’s sound waves that are being reversed, not time. The technique involves playing a sound (impulse) from a sound source—Anderson uses speakers for playing music through a computer or laptop—and using a sensor (like a microphone or a laser) at a targeted location on a metal plate to record the response to the impulse there.

That recording essentially maps the acoustic wave as it bounces around. One can then use software to reverse that signal and play it back so the waves retrace their steps and constructively interfere with each other, enabling Anderson to precisely focus that acoustic energy on the targeted location. The spatial extent of the focusing depends on the frequencies being used. Higher frequencies typically have smaller wavelengths, enabling Anderson to focus the acoustic energy to a more narrow point in space.

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#acoustics, #focused-vibrations, #lego, #natural-frequency, #science, #time-reversal

The Philharmonic Is Out of Its Hall This Year. It Doesn’t Pack Light.

With David Geffen Hall under renovation, the orchestra — and eight of its cellos, six double basses, six timpani and two grand pianos — must move from hall to hall.

#acoustics, #alice-tully-hall-manhattan-ny, #borda-deborah, #brey-carter, #classical-music, #geffen-david-hall-manhattan-ny, #lincoln-center-for-the-performing-arts, #new-york-philharmonic, #restoration-and-renovation, #rose-theater, #van-zweden-jaap

Study confirms superior sound of a Stradivari is due to the varnish

Violin against a red background.

Enlarge / A 1729 Stradivari known as the “Solomon, Ex-Lambert” on display at Christie’s in New York in March 2007. (credit: Don Emmert/AFP/Getty Images)

Along with Andrea Amati and Andrea Guarneri, Antonio Stradivari dominated the so-called Golden Age of Violins (roughly 1660 to 1750), and the instruments they crafted remain the gold standard today in terms of acoustic quality. World-renowned cellist Yo-Yo Ma has long favored a Stradivarius instrument, as does violinist Joshua Bell. But scientists have been arguing for years about precisely why these instruments have such superior sound. A recent paper published in the journal Angewandte Chemie confirms a theory dating back to 2006: the secret lies in the chemicals used to soak the wood, most notably borax, zinc, copper, alum, and lime water.

I’ve written extensively about this topic in the past. The (perceived) unique sound can’t just be due to the instrument’s geometry, although Stradivari’s geometrical approach did give us the violin’s signature shape. One hypothesis is that Stradivari may have used Alpine spruce that grew during a period of uncommonly cold weather, which caused the annual growth rings to be closer together, making the wood abnormally dense. Another prevailing theory has to do with the varnish: namely, that Stradivari used an ingenious cocktail of honey, egg whites, and gum arabic from sub-Saharan trees—or perhaps salts or other chemicals.

Then again, the difference may be all in our heads. A player’s instrument preference is highly subjective, and there’s some evidence of so-called “psychoacoustics” at play: that is, we’ve become so awed by the name Stradivarius that it influences how we evaluate or respond to the sound of one of Stradivari’s instruments.

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#acoustics, #antonio-stradivarius, #chemistry, #gaming-culture, #musical-instruments, #science, #stradivarius-violins

A Piece of Music Will Speak Once More. For 26 Hours.

“I am sitting in a room,” Alvin Lucier’s classic work of sound art, will be performed by 90 artists in honor of his 90th birthday.

#acoustics, #content-type-personal-profile, #i-am-sitting-in-a-room-musical-work, #issue-project-room, #lucier-alvin-1931, #music, #voice-and-speech

Listen to haunting notes from an 18,000-year-old conch shell trumpet

Color photo of a person with a conch shell raised to their mouth, silhouetted against a red-painted cave wall.

Enlarge / Archaeologists in 1931 found the conch shell near the entrance of Marsoulas Cave. This is a reconstruction of where and how the shell might have been played. (credit: G. Tosello)

After 18,000 years of silence, an ancient musical instrument played its first notes. The last time anyone heard a sound from the conch shell trumpet, thick sheets of ice still covered most of Europe.

University of Toulouse archaeologist Carole Fritz and her colleagues recently recognized the shell as a musical instrument. To understand more about how ancient people crafted a trumpet from a 31cm (1 foot) long conch shell, the archaeologists used high-resolution CT scans to examine the shell’s inner structure: delicate-looking whorls of shell and open chambers, coiled around a central axis, or columella. A series of overlapping photographs and careful measurements became a full-color, 3D digital model of the shell, and image enhancement software helped reveal how Magdalenian people had decorated the instrument with red ocher dots.

And in a lab at the University of Toulouse, a horn player and musicology researcher became the first person in 18,000 years to play the conch shell. The musician blew into the broken tip, or apex, of the shell and vibrated his lips as if he were playing a trumpet or trombone. Very carefully, he coaxed three loud, clear, resonant notes from the ancient instrument:

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#acoustics, #ancient-people-did-stuff, #anthropology, #archaeology, #cave-paintings, #conch-shells, #experimental-archaeology, #ice-age, #magdalenian, #music, #musical-instruments, #musicology, #paleolithic-europe, #science

In the Oceans, the Volume Is Rising as Never Before

A new review of the scientific literature confirms that anthropogenic noise is becoming unbearable for undersea life.

#acoustics, #animals, #biodiversity, #fish-and-other-marine-life, #law-of-the-sea-un-convention, #noise, #oceans-and-seas, #reefs, #ships-and-shipping, #united-nations-convention-on-biological-diversity, #whales-and-whaling, #your-feed-animals, #your-feed-science

Could Listening to the Deep Sea Help Save It?

In the abyss, everyone can hear you scream.

#acoustics, #animal-behavior, #biodiversity, #chen-chong, #dolphins-and-porpoises, #fish-and-other-marine-life, #japan, #noise, #oceans-and-seas, #recording-equipment, #ships-and-shipping, #volcanoes, #your-feed-animals, #your-feed-science

MIT develops a battery-free method for navigating underwater that could transform ocean exploration

MIT has developed a new navigation system designed for use underwater that could do for underwater wayfinding what GPS has done for travel on and above the surface. GPS doesn’t really penetrate underwater, because radio waves aren’t really water-friendly. It’s why you commonly see things like sonar employed on submarines, which emit sound waves and measure their reflection off of other underwater objects and surfaces. Typical sonar and other acoustic signalling methods are power-hungry, however – which is why MIT’s new battery-free system has so much potential.

GPS is also a relatively power-efficient technology, which is part of the reason it has done so much to transform how we get around, from in-car navigation to maps on smartphones. The limitations of current underwater navigation technology has meant that we typically need to use large, quick-to-deplete battery packs to power sound generation and transmission devices. MIT’s system would replace all that with a new type of battery-free acoustic navigation systems that sues signals already found in the environment rather than creating its own.

The system works by employing piezoelectric materials, which generate an electric charge when hit with mechanical stress, including the strain resulting from a sound wave impacting against them. Researchers created a way from these sensors to translate sound wave information into binary code, which they used to measure things like the temperature of the surrounding ocean or its salt content, but they theorized that it could also be used to figure out location information.

That’s more complicated than it might appear rat first, because sound reflects off of various surfaces underwater and travels back at often unpredictable angles. But the research team was actually able to account for this with an approach called ‘frequency hopping’ and collecting information across a range of different wavelentghts. This was effective in deep water, and now they’re working on making it more effective in the even noisier environment of shallow water.

Ultimately, the system and future versions that are based upon the same technology could enable future robotic submarine explorers to better map the ocean floor, and perform all kinds of automated monitoring and sub-sea navigation.

#acoustics, #gps, #in-car-navigation, #mit, #navigation, #navigation-system, #science, #science-and-technology, #ships, #smartphones, #sonar, #sound, #submarine, #tc

“Stonehenge Lego” scale model reveals the pagan monument’s unique soundscape

Adorable scale model of Stonehenge inside a large room.

Enlarge / Acoustic research using a scale model 1/12th the size of Stonehenge finds that the completed monument would have magnified speech and improved musical sounds, but only for those inside the stone circle. (credit: Acoustics Research Centre/University of Salford )

Scientists built a scale model of Stonehenge, the famous megalithic structure of stones in Wiltshire, England, and used it to recreate how sound would have been reflected off the surfaces of the stones. They found that the arrangement of the stones likely would have amplified speech and enhanced music but only if one was within the circle, according to a recent study in the Journal of Archaeological Science.

Dubbed “Stonehenge Lego,” the scale model is the work of acoustical engineer Trevor Cox of the University of Salford in England and several colleagues. (Fun fact: way back in 2007/2008, Cox conducted a yearlong study to identify the top 10 worst sounds. The sound of someone vomiting topped the list, followed by microphone feedback, wailing babies, and a train scraping along the track rails.) This latest paper builds on their preliminary findings last year. They’ve since been working on testing the acoustics of different configurations of the stones that would have existed at different times in the monument’s long history.

Recreating historical “soundscapes” is part of a relatively young field known as acoustic archaeology (or archaeoacoustics). For instance, researchers have sought to understand how acoustics may have influenced the outcome of key Civil War battles, like the Battle of Seven Pines on May 31, 1862. Another effect of interest to acoustic archaeologists is the chirping sound—reminiscent of the call of the quetzal, a brightly colored exotic bird native to the region—when you clap your hands at the bottom of one of the massive staircases of the Mayan Temple of Kukulkan at Chichen Itza in central Mexico.

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#acoustics, #archaeological-acoustics, #archaeology, #gaming-culture, #physics, #science, #stonehenge

Can You Hear Yourself Think?

Working from home often means having to cope with street noise and the clamor of children and pets. Here are some tips on how to quiet things down.

#acoustics, #content-type-service, #home-repairs-and-improvements, #interior-design-and-furnishings, #noise, #quarantine-life-and-culture, #real-estate-and-housing-residential, #telecommuting, #windows

How a Historian Stuffed Hagia Sophia’s Sound Into a Studio

Bissera Pentcheva used virtual acoustics to bring Istanbul to California and reconstruct the sonic world of Byzantine cathedral music.

#abel-jonathan-s, #acoustics, #cappella-romana-music-group, #hagia-sophia-istanbul-turkey, #music, #pentcheva-bissera