Abstract
Concert hall acoustics influence the emotional impact of music
Aalto University researchers found that the emotional impact experienced by music listeners depends on the concert hall’s acoustics.
Earlier research has shown that the strongest emotional experiences by music listening may elicit shivers or goosebumps in the listener. Much weaker reactions can be detected from the variations in the electrical skin conductance. Based on this knowledge, the researchers presented the test subjects with an excerpt of Beethoven’s symphony with the acoustics measured in different concert halls. During listening, the skin conductance was measured with sensors attached in the listeners’ fingers in order to record the magnitude of the emotional reactions to different acoustic conditions.
The results revealed that an identical performance of classical orchestra music evoked stronger emotional impact when presented in the acoustics of shoebox-type concert halls, such as Vienna Musikverein or Berlin Konzerthaus. The study included identically selected two positions from six European concert halls: Vienna Musikverein, Amsterdam Concertgebouw, Berlin Konzerthaus and Philharmonie, Cologne Philharmonie, and Helsinki Music Centre.
Dr Jukka Pätynen says, Some interpretations of a same music piece can evoke stronger emotions than others. Similarly, our study has succeeded in demonstrating that the hall’s acoustics plays an important part in the overall emotional impact. After all, emotional experiences are a key factor in music to many listeners.
For decades, researchers on concert hall acoustics have aspired to explain the acoustical success of certain halls with room-acoustic parameters. The study by Finnish researchers is the first to assess the acoustics of existing concert halls as the emotional impact.
Dr Jukka Pätynen works as an Academy of Finland post-doctoral researcher in Professor Tapio Lokki’s Virtual Acoustics research group. The group aims to understand how room acoustics affect sound signals, and how people perceive room-acoustic properties. Research focuses on improved prediction and understanding of concert halls and other acoustically demanding spaces.
For more information, follow the link: https://www.sciencedaily.com/releases/2016/03/160323082708.htm
Infrasound from tornados: theory, measurement, and prospects for their use in early warning systems
Infrasound is propagating sound waves with frequencies below the range of human hearing. A practical frequency range for infrasound that will propagate over long distances is 0.01–20 Hz. The lower frequency cut off for propagating infrasound arises because the buoyancy of parcels of air becomes comparable to the pressure gradient forces of acoustic waves at sufficiently low frequencies. The precise frequency for this cut off occurs at the Brunt–Väisälä frequency (Stull, 1995), the exact value of which depends on details of the vertical profile of the atmosphere.
One of the more famous examples of long-range propagating infrasound is the explosive eruption of Krakatoa Volcano in Indonesia. Audible sounds were heard as far away as 5000 km, and low-frequency infrasound signals with periods greater than 1 min were propagated around the Earth at least seven full times (e.g. Fee and Matoza, 2013).
Because infrasound propagates over a long range, it can be used for hazard monitoring. For volcanic warnings, atmospheric blasts can be detected by infrasound stations even when the peak of the volcano is obscured by clouds so that optical observations are not possible. Another important infrasound source is hurricanes, which produce characteristic tone-like signals called “microbaroms” produced by the nonlinear interaction between ocean waves and the atmosphere (Waxler and Gilbert, 2006). It was reported by Raveloson et al. (2012) that infrasound signals from the 2011 Tohoku-Oki, Japan, earthquake could have been used as an early warning of the impending tsunami.
Tornados represent one of the most common natural hazards posed in the USA. Within any given year, on average, some 800 tornados will occur within the USA, east of the Rockies, resulting in 80 deaths and 1500 injuries (National Oceanic and Atmospheric Administration (NOAA) National Severe Storms Laboratory). Despite the mystique associated with “Tornado Alley” (typically listed as the states of Oklahoma, Kansas, and Nebraska as well as adjoining areas from neighboring states), southern states, including Mississippi, remain a primary target for tornadic activity.
For more information, follow the link: http://acousticstoday.org/infrasound-tornados-theory-measurement-prospects-use-early-warning-systems-carrick-talmadge/
Mapping whale brains for sound effects
Can powerful noises affect whales? There is circumstantial evidence to suggest that they might. Now a team of researchers is attempting to find out for sure.
The notion that at least some species of whales might be adversely affected by loud noises rests on two pillars. First, the cetacean world is one of sound, rather than vision; toothed whales use echolocation to find their way around and locate prey; and several species of baleen whales in particular emit deep vocalizations that can travel hundreds, and possibly thousands, of miles across the ocean.
Second, there have been more than a few occasions on which whales have beached or been found dead in close proximity to a powerful noise source.
In particular, accusatory fingers have frequently been pointed at military use of powerful active sonar, which has been linked to numerous cases of strandings and death, particularly in various beaked whale species. While few, if any, of the individual cases can be linked unequivocally to a specific use of sonar, the accumulation of incidents is making a powerful case for the prosecution. Some have theorized that the sound panics the whales, forcing them to flee to the surface too quickly, causing them to suffer from rapid decompression.
But there is still surprisingly little clarity on the precise mechanisms by which sound could impact a cetacean, or even how an external source would propagate inside a cetacean’s head—a hole in the knowledge base that a joint US-Swedish team is attempting to fill.
In a recent paper in the online journal PLoS ONE, scientists from San Diego State University, University of California, San Diego, and the Kolmarden Zoo in Sweden developed an approach that “integrates advanced computing, X-ray CT scanners, and modern computational methods that give a 3D simulated look inside the head of a Cuvier’s beaked whale”—the species seemingly most affected by active sonar tests.
Petr Krysl of UC San Diego says, Our numerical analysis software can be used to conduct basic research into the mechanism of sound production and hearing in these whales, simulate exposure at sound pressure levels that would be impossible on live animals, or assess various mitigation strategies.
It is just the first step in an ongoing effort to understand what goes on—at least on one level—inside a beaked whale’s head. It does not definitively answer whether Navy sonar is killing cetaceans—yet. But by creating a greater understanding of the pathways by which sound travels inside a whale brain, it may very well help answer that question in the future.
“We believe that our research can enable us to understand, and eventually reduce, the potential negative effects of high-intensity sound on marine organisms”, says Krysl.
For more information, follow the link: http://news.discovery.com/earth/mapping-whale-brains-for-sound-effects.htm
International Qantas flight makes emergency landing in Brisbane due to engine “vibration” issue
A third Qantas flight in a week has made an emergency landing after a Japan-bound flight was forced to return to Brisbane due to an unknown “vibration” issue.
Flight QF61 headed for Tokyo made an unscheduled return to Brisbane 30 min into the flight when the pilots noted a mechanical issue in one of the plane’s engines. Engineers have been examining the Airbus A330 aircraft but the cause of the vibration is not yet known. The plane landed safely and passengers were put up in hotels in Brisbane overnight.
It was the second mechanical-related emergency landing for a Qantas flight in a week after an A380 plane en-route from Melbourne to Dubai was forced to land in Sydney, Tuesday, due to a mechanical issue.
The plane was flying over central Australia when the pilot made the decision to turn back, circling above New South Wales for hours before landing in Sydney on Tuesday morning. The problem was noted hours into the trip when the plane was over Western Australia.
The flight, carrying 410 passengers, left Melbourne on Monday night and circled above Sydney for several hours before it touched down safely just before 7 a.m. on Tuesday. One passenger described the ordeal as a “minor inconvenience”.
“We were kept well informed and it’s better to be safe then sorry”, Bree Turner told Yahoo7. The airline quoted engine trouble as the reason behind the emergency landing. Photo: Supplied. The flight was in the air for 8 h, enough time to travel to Indonesia or Malaysia.
On Friday, another Qantas flight from Melbourne to London was forced to make an emergency landing in Oman after a man suffered a heart attack on board.
For more information, follow the link: https://au.news.yahoo.com/a/31312466/international-qantas-flight-makes-emergency-landing-in-brisbane-due-to-engine-vibration-issue/