Woodbury, New York, March 10, 1999 (UPDATED)
What talent might insect-eating bats possess that most human musicians would envy? Can the sounds of a person's voice reveal warning signs of suicide? How might the naturally occurring background noise in the Arctic Ocean provide indications of climate change?
These questions are all explored in the science of sound--otherwise known as die Akustik, les acoustiques, acoustics and many other names around the world. Researchers will be gathering at what is expected to be the largest meeting ever devoted exclusively to this scientific discipline: the joint 137th Meeting of the Acoustical Society of America and the 2nd Convention of the European Acoustics Association integrating the 25th German Acoustics DAGA Conference, to be held March 14-19, 1999 at the Technical University of Berlin in Germany.
Approximately 1,950 abstracts of meeting papers have been submitted by acoustical scientists and engineers from 44 countries, including Germany, the United States, the UK, Russia, France, Japan, Brazil and many others. Therefore, this meeting is poised to break the record attendance set by last year's joint meeting of the International Congress on Acoustics and the Acoustical Society in America in Seattle, where 1,600 papers were delivered.
The ASA is the largest scientific organization in the United States devoted to acoustics, with nearly 7000 members. Founded in 1992, EAA provides services to 25 acoustical societies throughout Europe with more than 8500 individual members. One of these member societies is Deutsche Gesellschaft fuer Akustik--the German Acoustical Society.
The opening ceremony will be held in the Berlin Philharmonic Hall on Monday morning, March 15 at 10:00 a.m. On Sunday, March 14, there will be a guided tour on the architectural acoustics of the Berlin Parliament House (Preussischer Landtag) and Konzerthaus (another well-known concert hall different from the philharmonic hall) in Berlin. Tours to various labs at the Technical University of Berlin will take place during the week of the meeting.
Information on traveling to the meeting can be obtained at http://forum99-asa.tu-berlin.de/fp_travel.html. Reporters interested in attending the meeting should pre-register by returning the form at the end of the release, or register on-site by supplying the appropriate credentials.
Before and during the meeting, we encourage you to visit ASA's " Press Room" (http://www.acoustics.org). Right now, you can access an online version of the meeting program and learn about the ASA Science Writing Contest (the deadline for this year's award is Monday, February 15.) Starting on February 26, we will post lay-language versions of many meeting papers.
Are Day-Care Centers Dangerously Noisy? Refrigerator Music Acoustical Warning Signs of Suicide Risk Images of Sound Waves at the Nanometer Scale Do Bats Have Perfect Pitch? A Real-Life WB Frog? Ancient Greek Theaters Shakespeare's Globe Theater The Silent Flight of the Owl Silicon Microphones The Secrets of Swing The Memory of Rocks Acoustic Weapons? Listening for Arctic Climate Change with Naturally Occurring Noise The Comprehensive Nuclear Test Ban Treaty (CTBT) Why Seals Don't Have Sonar Sound Waves Reveal Intense Turbulence in Middle Atmosphere Unplugged Singers and a Virtual Band Acoustic Fatheads New and Renovated Concert Halls
Anyone who has every visited a day-care center knows that it can be a very clamorous environment. After conducting extensive measurements at numerous facilities, Michel Picard (email@example.com) and Chantal Boudreau, both at the University of Montreal, have accumulated evidence which suggests that their noise levels may often be dangerous to children's hearing. Collecting noise measurements at 25 day-care sites with 4-16 children each, the researchers measured sound levels that frequently exceeded levels considered safe for children. According to the researchers, "This suggests that children may be at risk of noise-induced hearing loss dependent on the length of stay in the day-care centers." Moreover, the researchers observed that the children can often communicate effectively only by employing extreme vocal exertion to make their voices heard above the racket. (Paper 3aNSa1)
Researchers will present new (and sometimes unconventional) uses for an innovative, environmentally friendly refrigerator design known as a thermoacoustic refrigerator. In this design, researchers broadcast sound waves through a container filled with inert gas, which takes the place of toxic or ozone damaging refrigerants such as CFCs. The sound waves create areas of compression and expansion in the gas, resulting in hot and cold regions which can then be tapped to chill objects. Werner Lauterborn at the University of Goettingen in Germany (firstname.lastname@example.org) and his colleagues ran a thermoacoustic design in reverse--by applying a temperature difference across the chamber--causing it to generate musical tones when they opened the chamber. Lauterborn will present musical sounds from such devices and discuss novel musical instruments that may be possible with this approach--including trombone-like contraptions and "thermoacoustic organs" (2aPAa3). Gregory W. Swift of Los Alamos National Lab (email@example.com) has built a thermoacoustic natural-gas liquefier, which cools and liquefies a stream of methane gas (2aPAa1). Scott Backhaus of Los Alamos (firstname.lastname@example.org) will present the most efficient thermoacoustic refrigerator yet one that operates according to a sequence of steps known as the Stirling cycle (2aPAa2).
After many years of experience in emergency rooms and office consultations with suicidal patients, clinical professionals can often successfully detect at-risk patients. While such professionals typically listen very closely to the content of a patient's words, they often detect warning signs just by listening to the sound of the patient's voice. Many professionals have identified a distinctly "hollow" or "toneless" quality in the voices of these patients. Motivated by these qualitative descriptions, Richard Shiavi and colleagues at Vanderbilt University (email@example.com) have set out to quantify these vocal patterns, with the goal of developing an acoustical tool that can aid professionals in identifying at-risk patients. Lacking other means to perform a controlled study, the researchers analyzed suicide notes left on tapes recorded by survivors, recordings of patients that required hospitalization, and recordings of 911 calls. According to the researchers, "Preliminary results suggest that the frequency spectrum patterns of the suicidal voice may have utility in the assessment of near-term risk. " (4aSCb12)
Studying how sound waves pass through materials at the atomic and molecular level can give important information on a material's basic properties, such as its elasticity. At session 2aPAb, researchers will present new methods that make this possible for the first time. These methods can capture details in sound waves as small as 50 nanometers (billionths of a meter). To accomplish this, numerous groups have combined conventional acoustic imaging techniques with such devices as the atomic force microscope, which can take snapshots of surfaces at the atomic and molecular scale. Among the speakers to be presenting images and techniques: Eduard Chilla, Paul-Drude Institute for Solid State Electronics, Germany, firstname.lastname@example.org (2aPAb1); Andrew Kulik, Federal Polytechnic School, Switzerland, email@example.com (2aPAb2); Ute Rabe, Fraunhofer Inst. for Nondestructive Testing, Germany, firstname.lastname@example.org (2aPAb3)
Certain animals, such as bats and dolphins, perceive their environment through natural sonar systems, in which they broadcast sound at objects and listen to their echoes to obtain detailed representations of them. New experiments suggest that bats may have something that most human musicians envy: perfect pitch, the ability to recognize the pitch of a particular echo tone in isolation rather than in relation to other tones, which is what most human musicians have to do when they hear musical notes. Sabine Schmidt of the University of Munich (email@example.com) will describe how this ability may allow bats to build an "acoustical library" for identifying objects (4aABb3). Determining how bats use their sonar to recognize the textures of different surfaces in their environment, Rolf Mueller (firstname.lastname@example.org) and Roman Kuc of Yale University (email@example.com) have incorporated these properties into an artificial system that can distinguish between different types of trees. And if you've ever wondered what it's like to be one of these creatures, the researchers will play audible versions of the sounds that a bat hears when it operates its sonar. Mueller and Kuc use the term "acoustic ecology" to describe their work on characterizing the bat's sonic environment (2pAB8).
In a rain forest in East Madagascar, Peter Narins of UCLA (firstname.lastname@example.org) and his colleagues have discovered a creature with the largest known vocal repertoire of any amphibian. Known as Boophis madagascariensis (Rhacophoridae), it produces call notes that can be classified into 28 types. The animals produced notes inconsistently and unpredictably. Narins will discuss the evolutionary significance of an extended vocal repertoire and a random call note production scheme (3aABa3). In a sense, this amphibian may be the closest thing to a real-life version of "Michigan J. Frog"--the animated amphibian first featured in a 1955 Warner Brothers cartoon, which showed it singing a wide range of songs but never at the behest of its owner.
Often very large or in noisy environments, modern open-air theaters are endowed with electrical amplification that allow performers' voices to travel to the farthest reaches of the audience. Paradoxically, reliance on these amplification systems has retarded the pace of innovation in modern-day designs of open-air theaters. Emmanuel G. Tzekakis of Aristotle Univ. of Thessaloniki in Greece (email@example.com) will describe the design of a 5000-seat outdoor theater based on ancient Greek prototypes, and intended to provide the best possible sound without electrical amplification (2pAAa1). His colleague, acoustical consultant Gottfried Schubert, will discuss myths and realities of the acoustical properties of relatively well-preserved theaters of ancient Greece. These include the Dionysus Theater of Athens and the Epidaurus Theatre, which is used for modern theater festivals (2pAAa2).
Russell Richardson of South Bank University in England (firstname.lastname@example.org) will describe acoustical measurements of Shakespeare's Globe Theater. Built for William Shakespeare's company of actors in the late 16th century, the theater was recreated and reopened for performances in the summer of 1997. Making careful measurements of the restored theater's acoustical properties, the authors find that the speech in the new theater is intelligible, but achieving an adequate volume level is more of a problem. (2pAAa3)
Next-generation commercial aircraft, such as the proposed Airbus A3XX, will be so large that they will likely create a significantly greater amount of noise, especially during landing, in part because they will require extended landing gear. To make these aircraft as quiet as possible, researchers are not only testing their designs in wind tunnels and computer simulations. They are looking to the owl--whose remarkably silent flight results from its feathers, which have features different from all other birds. Geoffrey M. Lilley of NASA-Langley and the University of Southampton in England (email@example.com) will discuss new experiments exploring the noise-minimizing effects of the owl's feathers and the reasons why the owl remains silent to its prey even though they have excellent hearing in the high-frequency range. (1pNSd1)
In the same way that transistors replaced bulky vacuum tubes in computers, researchers are aiming to supplant conventional microphones with a new generation of tiny microphones that can fit on silicon chips with other electronic components. Marc Fischer and Gerhard Sessler of the Darmstadt University of Technology (firstname.lastname@example.org) will present several experimental designs, many of which employ new sound- recording principles not possible with conventional designs (2aEA1). Allan D. Pierce and colleagues at Boston University (email@example.com) will describe an underwater acoustic sensor built with an emerging technology known as microelectromechanical systems (MEMS)--in which various sensors and mechanical devices are constructed on a single chip (2aEA5). Joerg Sennheiser, the chairman of Germany's Sennheiser Electronics, will demonstrate of a microphone that does not need an outer "membrane"--the part of the microphone that affects the quality most (2aEA1). Wolfgang Niehoff of Sennheiser will demonstrate an optical microphone, in which sound is recorded by measuring changes in the intensity of a light beam inside the microphone (2aEA2).
When jazz and blues musicians read sheet music containing a sequence of notes with equal length, they often play these notes in a pattern in which a long note alternates with a short note. Studying recordings of professional jazz drummers, Anders Friberg and colleagues at the Royal Institute of Technology in Sweden (firstname.lastname@example.org) noted the swing ratio--the ratio between the length of the long note to that of a short note. They found that the ratio was not constant for fast and slow sounds, but instead varied greatly with the tempo: ranging from 3.5 to 1 for slow tempos to roughly 1 to 1 for fast tempos. Interestingly, they found the length of the short note was about the same for all tempos--about a tenth of a second. According to Friberg, this provides information about the role of a short note in a swing rhythm (5aMUb10). Observing arm motion, timing, and striking force in drummers, Sofia Dahl of the Royal Institute of echnology (email@example.com) and a colleague studied how the drummers played differently depending upon the type of surface that was struck (5aMUa5).
Rocks have some very unusual properties that researchers are only beginning to discover. As explained by James A. TenCate of Los Alamos (firstname.lastname@example.org), repeatedly expanding and compressing sandstone rock with high-magnitude strain forces can "condition" the rock to respond with less stiffness to the applied forces after a few minutes, so that it behaves like a softer spring. Intriguingly, the rock remains soft for minutes or even hours, constituting a sort of "memory" of the past forces applied to it (4aPAc11). Paul Johnson of Los Alamos (email@example.com) will describe how the rock's elastic properties seem to originate from processes at the mesoscopic scale (between the microscopic and the macroscopic), unlike liquids and crystalline solids, whose elasticity properties are determined by atomic-scale forces. Surprisingly, the researchers discovered damaging an atomic elastic material" causes it to behave like a "mesoscopic" elastic material (4aPAc9).
The world already faces threats from biological, chemical, nuclear, and artillery weapons. Now, some military publications have printed unconfirmed reports that several nations are conducting research on using intense sound as a weapon, often as a nonlethal agent that causes no permanent damage but is nonetheless insidious. According to Juergen Altmann of the University of Dortmund and Ruhr University-Bochum in Germany (Altmann@EP3.Ruhr-Uni-Bochum.DE), many of these reports focus on the use of powerful blasts of infrasound, sound waves too low-pitched to hear. According to these reports, intense levels of infrasound can trigger non-lethal effects in humans such as nausea and vomiting; for inanimate objects, they allegedly can cause embrittlement of metals and even local earthquakes. While Altmann could not confirm many of these effects in a thorough review of the literature, he did find evidence of non-auditory effects caused by the application of low-pitched audio above 150 decibels; in addition, very strong blast waves at higher frequencies can cause lung rupture and death. Altmann says that protective bans on such weapons should not be restricted to warfare because such tactics, especially the nonlethal ones, could be used for riot control and protection of property. (Papers 2aPPb10 and 2aPPb12)
The Arctic Ocean and its surroundings exert a profound influence in the world's climate; scientists and others are concerned that the melting of glaciers and rises in sea level would drastically alter the world's climate. To measure climate variability and look for signs of global warming in this part of the world, a Norway-UK-Germany-Russian collaboration has embarked on a program called AMOC short for Acoustic Monitoring of the Ocean Climate in the Arctic Ocean AMOC researchers have been developing and designing an acoustic system for long-term monitoring of the ocean temperature and ice thickness in the Arctic Ocean and surrounding areas. Ola M. Johannessen (Ola.Johannessen@nrsc.no) of the Nansen Environmental and Remote Sensing Center (NERSC) in Norway will give an overview of the system (3aAOb4) and Hanne Sagen of NERSC (firstname.lastname@example.org) will present preliminary results. (3pAOb10) In addition to the more conventional acoustical techniques that are being used, Sagen will describe how listening to the naturally present "ambient" noise in the ocean can provide additional indications of climate change in the environment (3aAOb6).
Signed by 149 countries at the end of 1996, the Comprehensive Nuclear Test Ban Treaty (CTBT) is a global moratorium on nuclear weapons testing. To verify the treaty, scientists are building a worldwide network of 337 monitoring stations. At session 2aUWa, Martin Lawrence of the CTBT Organization in Vienna, Austria (email@example.com) and others will report the latest progress on 11 hydroacoustic stations that would detect nuclear explosions and shock waves travelling underwater. At session 2pUWa, Douglas Christie of the CTBT Organization (firstname.lastname@example.org) and others will describe another part of this network, a 60-station array that can detect infrasound, sounds too low-pitched for the human ear to hear. Such a network, says Christie, will not only detect the distinctive infrasound signature of a nuclear blast, but also a wide range of man-made and naturally occurring sources, including large chemical explosions, meteors, and volcanic explosions. And it will also provide fundamental knowledge, as the propagation of infrasound in the atmosphere is still not completely understood (2pUWa1).
Why do certain evolutionary relatives of dolphins--such as sea lions--completely lack sonar systems even though they live in similar environments? The reason, argues Ronald Schusterman of UC-Santa Cruz (email@example.com) and colleagues, is that sea lions and other "pinnipeds" are true amphibians which perform reproductive activities in many cases on land and ice. Such animals have to adapt their hearing systems for land as well as water. And they developed other talents too--Schusterman will describe observations of an elephant seal with eyes that become completely dark-adapted in the approximately 5 minutes it takes to dive from a bright surface to a depth of 500 meters. (4aABb5)
Computer models for forecasting weather have improved so greatly in resolution and sophistication that they call for similar improvements in making actual measurements of the atmosphere. To determine such properties as wind speeds and air temperatures, most people think of radar, which is based on radio waves, an invisible form of light. At sessions 5aPAb and 5pPAa, researchers will discuss advances in using sound waves to study the atmosphere. Sergei V. Shamanaeva of the Russian Academy of Sciences (firstname.lastname@example.org) will discuss the promise of using acoustic sensors to make detailed measurements of fog and rain (5pPAa5). Sergey N. Kulichkov, also at the Russian Academy of Sciences, has found that intense turbulence exists in the middle atmosphere (20-80 kilometers above ground) during all seasons (5aPAb4).
Ingo Titze of the University of Iowa (email@example.com) will describe why classical vocalists, who are trained to sing without electric amplification, often do not use their full vocal abilities. For example, they use falsetto voice sparingly because it does not balance with the chest voice in terms of loudness. For better or worse, electrical amplification removes the need to restrict these qualities (4aMU2). Esther J. Langeheinecke of the University of Tuebingen in Germany (firstname.lastname@example.org) will discuss the acoustical signatures of joy, fear, anger, and sadness in singing (5aMUb11). Tapio Lokki of the Helsinki University of Technology in Finland (Tapio.Lokki@hut.fi) will describe a virtual reality system in which a musical band with four animated musicians is controlled by a pair of users. One person moves a baton which controls the tempo of the band's music, and another controls the viewpoint of the audience (1pSP1).
Dolphins, seals, aquatic birds, and turtles often live in similar environments but their ears have strikingly different anatomies. Now, Darlene Ketten of the Woods Hole Oceanographic Institution and Harvard Medical School (email@example.com ) and colleagues have found a commonality: all of these creatures have bundles of fat emerging from the middle ear. The evidence suggests that these species evolved, in parallel, soft-tissue structures that conduct underwater sound very well. (3aABb3)
At sessions 1pAA and 2aAA, researchers will present detailed case studies of many new or recently renovated music halls. Henrik Moeller (firstname.lastname@example.org) will discuss the conversion of a German gothic cathedral--destroyed at the end of World War II--into Marienkirche concert hall, which is scheduled to open in fall 1999 (1pAA6). Karlheinz Mueller of Mueller-BBM in Germany will discuss The Festspielhaus in Bayreuth--the only opera house of the world founded and designed mostly by a composer Richard Wagner. (1pAA7) Yasuhira Toyota of Nagata Acoustics (email@example.com) will discuss the design of the Walt Disney Concert Hall, scheduled to open in downtown Los Angeles to serve as the home of the LA Philharmonic Orchestra and feature mainly orchestral music (2aAAa9). Christopher Jaffe will describe how the renovated Kennedy Center Concert Hall in Washington DC seems to defy conventional acoustical orthodoxy. The acoustics of the renovated concert hall is well regarded even though the values for a key acoustical parameter known as "midfrequency reverberation time" in the hall are much shorter than is believed required for acoustic excellence (2aAAa12).
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