By studying the aeroacoustics of a dental drill, researchers can pinpoint the anxiety-causing sounds and design drills to lessen them. #ASA_ASJ2025 #ASA189
HONOLULU, Dec. 2, 2025 — Dental anxiety, also known as odontophobia, prevents people from getting their regular cleanings and keeping up with necessary dental hygiene.
One aspect of the anxiety comes from the sound of the dental drill, which makes a high-pitched whining sound. As a dentist, Tomomi Yamada has witnessed discomfort and fear in her patients firsthand.
“Originally, I was doing research on dental materials, but I realized that almost no one — not even dentists — was tackling this sound problem scientifically,” Yamada said.
Yamada, an assistant professor at the University of Osaka’s graduate school of dentistry, will present her work Tuesday, Dec. 2, at 8:20 a.m. HST as part of the Sixth Joint Meeting of the Acoustical Society of America and Acoustical Society of Japan, running Dec. 1-5 in Honolulu, Hawaii.
A dental drill being used in a patient’s mouth. Credit: Tomomi Yamada
To understand the aerodynamics of the drill, Yamada and her collaborators from the University of Osaka, Kobe University, and National Cheng Kung University used Japan’s flagship supercomputer to conduct large-scale aeroacoustics simulations. They analyzed the internal and external airflow of the dental drill, which is powered by compressed air and rotates at about 320,000 revolutions per minute.
From these simulations, they were able to visualize how air moves through and around the drill to create the noise.
“Our research showed that just making the drill quieter isn’t enough to make the sound less unpleasant,” Yamada said. “What really matters is improving its sound quality.”
The researchers also tested the psychological effects of the dental drill, which can generate high-pitched sounds reaching nearly 20 kilohertz, with children and adults. They found that younger listeners had different reactions to the drill, perceiving the sounds as louder and more unpleasant.
“This indicates that children’s fear of dental sounds is not merely psychological but also physiological in nature,” said Yamada. “Children truly hear these sounds differently, so their fear of dental treatment is a genuine sensory response, not just imagination.”
To address this, Yamada and her colleagues are working on optimizing the blade geometry and exhaust port of the drill to minimize the noise while maintaining the performance.
To get the dental industry to adopt this new technology, achieving a balance between the device’s performance and safety is key, since a quieter drill won’t necessarily get the job done.
“Moving forward, we hope to work with dental manufacturers through industry–academia partnerships, progressing toward commercialization after completing the necessary regulatory and durability testing,” Yamada said.
Contact:
AIP Media
+1 301-209-3090
media@aip.org
——————— MORE MEETING INFORMATION ——————–
Main Meeting Website: https://acousticalsociety.org/honolulu-2025/
Technical Program: https://eppro02.ativ.me/web/planner.php?id=ASAASJ25
ASA PRESS ROOM
In the coming weeks, ASA’s Press Room will be updated with newsworthy stories and the press conference schedule at https://acoustics.org/asa-press-room/.
LAY LANGUAGE PAPERS
ASA will also share dozens of lay language papers about topics covered at the conference. Lay language papers are summaries (300-500 words) of presentations written by scientists for a general audience. They will be accompanied by photos, audio, and video. Learn more at https://acoustics.org/lay-language-papers/.
PRESS REGISTRATION
ASA will grant free registration to credentialed and professional freelance journalists. If you are a reporter and would like to attend the meeting and/or press conferences, contact AIP Media Services at media@aip.org. For urgent requests, AIP staff can also help with setting up interviews and obtaining images, sound clips, or background information.
ABOUT THE ACOUSTICAL SOCIETY OF AMERICA
The Acoustical Society of America is the premier international scientific society in acoustics devoted to the science and technology of sound. Its 7,000 members worldwide represent a broad spectrum of the study of acoustics. ASA publications include The Journal of the Acoustical Society of America (the world’s leading journal on acoustics), JASA Express Letters, Proceedings of Meetings on Acoustics, Acoustics Today magazine, books, and standards on acoustics. The society also holds two major scientific meetings each year. See https://acousticalsociety.org/.
ABOUT THE ACOUSTICAL SOCIETY OF JAPAN
ASJ publishes a monthly journal in Japanese, the Journal of the Acoustical Society of Japan as well as a bimonthly journal in English, Acoustical Science and Technology, which is available online at no cost https://www.jstage.jst.go.jp/browse/ast. These journals include technical papers and review papers. Special issues are occasionally organized and published. The Society also publishes textbooks and reference books to promote acoustics associated with various topics. See https://acoustics.jp/en/.
Employing low-frequency noise can help electric vehicles stand out in busy environments. #ASA_ASJ2025 #ASA189
HONOLULU, Dec. 1, 2025 — One of the many benefits of electric vehicles is that they are much quieter than traditional gasoline-powered vehicles. In some cases, though, they are too quiet. Automakers are required to design their vehicles so they emit sounds at low speeds to alert pedestrians to their presence.
However, aside from some basic regulations regarding volume, automakers are free to choose whatever noise they wish their vehicles to emit. This freedom gives researchers a unique opportunity to design custom sounds to maximize their effectiveness.
Graduate student Mei Suzuki will present her team’s efforts to design custom approach sounds for electric vehicles Monday, Dec. 1, at 2:35 p.m. HST as part of the Sixth Joint Meeting of the Acoustical Society of America and Acoustical Society of Japan, running Dec. 1-5 in Honolulu, Hawaii.
A listening test for an electric vehicle. Credit: Mei Suzuki
To test their library of created sounds, the team played them to volunteers, both in a studio and in real road conditions. They then asked the volunteers to rate each based on criteria such as “The sound has a sense of urgency” and “The sound is easy to notice.” The noises were then ranked based on this feedback.
They found the best performer was a version of pink noise — a type of noise dominated by lower-frequency notes.
“The reason this sound stimulus was rated highest was its strong low-frequency components and its similarity to automotive running noise,” said Suzuki.
This low-frequency noise distribution was less susceptible to being drowned out by other sources of ambient noise, which meant that approaching vehicles could be heard clearly by the volunteers in all conditions.
The researchers are planning to introduce similar sounds for electric bicycles, e-scooters, and other small lightweight mobility devices.
“Starting this year, we are conducting research on the sound design of approach warning sounds specifically for micromobility devices,” said Suzuki. “Since research on approach warning sounds for micromobility devices is largely unexplored, we believe this could contribute to reducing collisions involving pedestrians and visually impaired individuals.”
Contact:
AIP Media
+1 301-209-3090
media@aip.org
——————— MORE MEETING INFORMATION ——————–
Main Meeting Website: https://acousticalsociety.org/honolulu-2025/
Technical Program: https://eppro02.ativ.me/web/planner.php?id=ASAASJ25
ASA PRESS ROOM
In the coming weeks, ASA’s Press Room will be updated with newsworthy stories and the press conference schedule at https://acoustics.org/asa-press-room/.
LAY LANGUAGE PAPERS
ASA will also share dozens of lay language papers about topics covered at the conference. Lay language papers are summaries (300-500 words) of presentations written by scientists for a general audience. They will be accompanied by photos, audio, and video. Learn more at https://acoustics.org/lay-language-papers/.
PRESS REGISTRATION
ASA will grant free registration to credentialed and professional freelance journalists. If you are a reporter and would like to attend the meeting and/or press conferences, contact AIP Media Services at media@aip.org. For urgent requests, AIP staff can also help with setting up interviews and obtaining images, sound clips, or background information.
ABOUT THE ACOUSTICAL SOCIETY OF AMERICA
The Acoustical Society of America is the premier international scientific society in acoustics devoted to the science and technology of sound. Its 7,000 members worldwide represent a broad spectrum of the study of acoustics. ASA publications include The Journal of the Acoustical Society of America (the world’s leading journal on acoustics), JASA Express Letters, Proceedings of Meetings on Acoustics, Acoustics Today magazine, books, and standards on acoustics. The society also holds two major scientific meetings each year. See https://acousticalsociety.org/.
ABOUT THE ACOUSTICAL SOCIETY OF JAPAN
ASJ publishes a monthly journal in Japanese, the Journal of the Acoustical Society of Japan as well as a bimonthly journal in English, Acoustical Science and Technology, which is available online at no cost https://www.jstage.jst.go.jp/browse/ast. These journals include technical papers and review papers. Special issues are occasionally organized and published. The Society also publishes textbooks and reference books to promote acoustics associated with various topics. See https://acoustics.jp/en/.
Andrew Brown – andrewdb@uw.edu
University of Washington, Department of Speech and Hearing Sciences, Seattle, WA, 98105, United States
Additional authors: DJ Audet Jr, Aoi A. Hunsaker, Mallory Butler, Carol Sammeth, Alexandria Podolski, Theodore F. Argo, David A. Anderson, Nathaniel T. Greene,
Popular version of 2pNSa4 – Two-dimensional sound localization during hearing protector use in a large sample of human listeners
Presented at the 189th ASA Meeting
Read the abstract at https://eppro02.ativ.me//web/index.php?page=Session&project=ASAASJ25&id=3982069
–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–
In noisy professions – from manufacturing to the military – hearing protection and perception are often at odds. The sense of hearing normally enables listeners to detect and locate sounds arriving from any direction – an especially valuable ability in settings with low visibility (darkness, fog, smoke), visual clutter, or in which important sound sources may be outside the field of vision altogether, whether off in the distance or “right behind you!” However, when noisy settings demand the use of hearing protectors (usually earplugs or earmuffs), the ability to determine sound direction is reduced. Hearing protectors lower the level of transmitted sound – their designed purpose – but they also change the quality of the transmitted sound, disrupting the subtle bits of acoustic information the brain relies on to determine sound direction. This means listeners may confuse forward and rearward sounds, or struggle to locate sounds overhead. The trade-off between protection and perception can contribute to disuse of hearing protectors in critical settings where situational awareness and personal safety may be acutely valued above long-term hearing health.
Methods to evaluate hearing protector impacts have varied widely across previous studies; hearing protectors come in many shapes and sizes, and directional hearing ability varies across people even before hearing protectors enter the picture. Here, in an effort to identify key factors that mediate hearing protector impacts, we measured directional hearing during hearing protector use in a large sample of listeners across two different sites (130 subjects enrolled study-wide). Listeners were asked to orient to sounds that varied in horizontal and vertical location while wearing a variety of commercially available hearing protector styles, with orientation accuracy measured using wireless sensors.
All hearing protectors reduced directional hearing ability, but variation across devices pointed to key variables that may impact performance – and may be captured using relatively simple acoustic measurements. This work is part of an effort to develop metrics beyond the industry-standard “Noise Reduction Rating” that consumers and hearing conservation professionals alike might use to select job-appropriate hearing protectors, and that hearing protection manufacturers might leverage to design and build better devices.
This work was funded by the US Department of Defense Joint Warfighter Medical Research Program.
Alaa Algargoosh – algargoosh@vt.edu
Virginia Polytechnic Institute and State University (Virginia Tech), Perry St, Blacksburg, VA, 24061, United States
Megan Wysocki
Virginia Polytechnic Institute and State University (Virginia Tech)
Amneh Hamida
RWTH Aachen University.
Popular version of 1pNSa4 – Cognitive Restoration in Virtual Interactions with Indoor Acoustic Environments
Presented at the 189th ASA Meeting
Read the abstract at https://eppro02.ativ.me//web/index.php?page=Session&project=ASAASJ25&id=3977035
–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–
People often associate restorative experiences with nature: the sound of birds, wind, or flowing water. But what if indoor spaces could offer their own kind of mental escape, not through what we see, but through how we interact with sound?
This idea began with a simple observation. When you walk into a space and notice how your footsteps and voice are reflected back to you, the echoes create a subtle sense of awe. According to Attention Restoration Theory, experiences that evoke fascination and effortless engagement can help replenish mental resources. We wanted to explore whether these moments of acoustic interaction between a person and a space could invite gentle attention and, in turn, support cognitive restoration. In Attention Restoration Theory, this is referred to as soft fascination, a type of stimulus that is engaging but not overwhelming.
Exploring Echoes as a Path to Mental Restoration:
During a live demonstration at the MIT Museum, we used auralization a technology that allows you to hear your voice as if you were in a different place using that place’s sound signature or impulse response. A volunteer hummed into the acoustic signature of Hagia Sophia. Later, the entire audience hummed together and reflected on their experiences. The conversation pointed to the potential of such acoustic interaction to support a meditative state by impacting sense of space, time, and self.
This inspired a controlled experiment to study the restorative potential of indoor acoustic environments. We asked people to experience different sound environments (Figure 1) and measure their cognitive activity before and after each interaction. Early results suggest that interactive acoustics may support attention restoration depending on the acoustic characteristics, opening a new way of thinking about how sound affects us indoors.
Figure 1: Virtual interaction with an acoustic environment during the experiment, where a person hears their own voice transformed through the acoustic signature of another space.
Why does this matter?
We spend most of our time indoors, yet discussions of restorative environments often focus on natural settings. This is especially relevant for workplaces and schools, where mental fatigue is common. It may also hold meaningful promise for neurodivergent individuals, including those with ADHD, who often benefit from environments that support attention without overstimulating it.
We imagine applications in immersive restorative spaces where people can interact with sound to reset and return to their activities with greater clarity. We also envision subtle integration into transitional spaces such as staircases, corridors, and building entrances that provide gentle cognitive relief as people move throughout their day.
Sound(e)scape reframes acoustics not as background, but as a tool for well-being. By understanding how interactive sound shapes attention and cognition, we can design buildings that do not simply avoid harmful noise. They can actively help the mind take a restorative break.
Figure 2: Visualization of interacting with different acoustic environments. Left: A person vocalizing in an office environment (MIT Media Lab). Middle: “Hagia Sophia – Muhammad, Allah, Abu Bakr” by Rabe!, licensed under CC BY-SA 3.0 (https://commons.wikimedia.org/wiki/File:Hagia_Sophia_-_Muhammad,_Allah,_Abu_Bakr.jpg) Cropped and one person added by Alaa Algargoosh. Right: A person vocalizing in Boston Symphony Hall.
Sound recordings:
1. Vocalizing in an office environment (MIT Media Lab).
2. Virtual vocalization in Hagia Sophia.
3. Virtual vocalization in Boston Symphony Hall.
The virtual vocalizations were generated using the impulse responses available at ODEON software library.
Ki-Hong Kim – kim.kihong@surugadai.ac.jp
Faculty of Media and Information Resources, Surugadai University, 698 Azu, Hanno-shi, Saitama, 357-8555, Japan
Misaki Yamaguchi
Undergraduate School of Media and Information Resources
Surugadai University
Shin-ichiro Iwamiya
College of Art
Nihon University
Popular version of 1pNSb10 – The effects of visual content and gender on optimal listening levels in audio-visual productions
Presented at the 189th ASA Meeting
Read the abstract at https://eppro02.ativ.me//web/index.php?page=Session&project=ASAASJ25&id=3977078
–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–
Note on Publication
This article is a new version prepared for the Acoustics Lay Language Paper. Our research was originally published in the Journal of Music Perception and Cognition: Kim, K-H., Yamaguchi, M., Iwamiya, S. (2021). Optimal listening level for audio-visual media: Influence of gender difference, presence or absence of video, and display size. Journal of Music Perception and Cognition, 26(2), 67-80. (in Japanese with English abstract)
Tired of arguing with family or a partner over the TV volume? Someone often says it’s “too loud” while the other insists they “can’t hear it well.” This common conflict suggests that the preferred volume is not just an acoustic phenomenon. Our research reveals that gender and the presence or absence of video play a crucial role in determining the volume people find “just right.”
In our daily lives, we constantly process sound alongside visual cues. The preferred playback volume for a comfortable experience is known as the Optimal Listening Level (OLL). Our study demonstrates that simply measuring physical sound intensity is insufficient; we must adopt a multisensory approach to fully comprehend loudness perception.
To clarify the effects of video and gender on OLL, we examined twenty Japanese university students (10 men and 10 women). All participants used a remote control to adjust the volume freely until they reached their “most comfortable level” (OLL). They did this while watching various video clips of diverse genres or simply listening to the audio only. We then precisely measured the sound level at their ear position.
The Main Discovery: Video Affects Women’s Volume More Than Men’s
The most important finding is that the multisensory integration effect—the way we integrate sight and sound—is significantly stronger in women when setting the OLL:
1. Women Turn Up the Volume with Video
When women transitioned from listening to audio only to watching an audio-visual (AV) clip, they increased their preferred volume by an average of 1.7 dB (up to 3.3 dB). This increase was a statistically significant change, demonstrating that visual information leads women to set the volume louder.
2. Men’s Volume Setting Stays Consistent
For men, the addition of the video element resulted in no significant change in their OLL.
This indicates that female viewers tend to use visual context to modify their ideal sound level, a sensitivity that male viewers did not exhibit.
Figure 1: Gender differences in the multisensory integration effect on the Optimal Listening Level (OLL). † p< .10, * p< .05 , ** p< .01, n.s.: not significant
Other Findings
Beyond the influence of video, we confirmed other substantial factors influencing the OLL:
1. The Overall Gender Difference: Men Prefer It Louder
Across all experimental conditions, men consistently preferred a higher listening level than women. On average, the volume set by men was 5.3 dB higher than the volume set by women. This difference is large enough to be easily perceived as a noticeable difference in loudness. In this way, the gender difference was maintained regardless of whether the video was present.
2. The Influence of Content and Display Size
We also found that the preferred volume varied significantly based on the type of content. In particular, the listening level was notably higher for music-related productions (Pop and classical concerts) than for other genres. However, the size of the display (16-inch small vs. 46-inch large) had no significant effect on the volume setting.
Conclusions and Takeaways
To create a truly comfortable listening experience in movies, television, and gaming, we must look beyond sound alone. Recognizing gender differences and the multisensory interaction effects—specifically, the shift in women’s preferred volume with video—highlights the necessity of considering gender-specific viewing experiences in all AV productions. Adopting this approach leads to more inclusive AV experiences for all viewer-listeners.
Mark Anderson – anderson.mark.az@gmail.com
X: @AerospaceMark
Brigham Young University, Provo, UT, 84602, United States
Additional Authors
Kent L. Gee
X: @KentLGee
Brigham Young University
Lucas K. Hall
California State University Bakersfield
Institutional Social Media
Brigham Young University
X: @BYU
Instagram: @brighamyounguniversity
Department of Physics and Astronomy
X: @BYU_PhysAstro
Popular version of 2aNSb9 – Modeling seasonal variation in rocket ascent sonic booms
Presented at the 189th ASA Meeting
Read the abstract at https://eppro02.ativ.me//web/index.php?page=IntHtml&project=ASAASJ25&id=3989257
–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–
Residents in Southern California have reported hearing sudden, explosion-like sounds that have been startling individuals and causing vibrations in buildings. It turns out, these sounds are actually the sonic booms from rockets launched 70 or more miles away. And whether you’ll hear one is often determined by the season.
These sonic booms are produced during the rocket’s ascent toward orbit (see Fig. 1). As the vehicle pitches over during flight, it produces a sonic boom that can hit the ground below. This has happened with every orbital rocket, including the Saturn V and Space Shuttle, all the way to the modern Falcon 9. The difference is that while, historically, these sonic booms have only been audible over the ocean, rockets today are being launched closer to the coast, making these sonic booms audible on land.
A SpaceX Falcon 9 rocket launches to orbit. Photo credit: SpaceX. CC BY-NC 2.0 (https://www.flickr.com/photos/spacex/51027443336/). Annotation by the authors.
As part of a project funded by Vandenberg Space Force Base, researchers at Brigham Young University and California State University Bakersfield have teamed up to measure these rocket ascent sonic booms. Almost immediately, a question arose: why is it that we can measure sonic booms on land for a few months, followed by a period of almost nothing, even if the rocket’s trajectory stays the same? To answer this question, we used NASA’s state-of-the-art sonic boom modeling software, PCBoom. After verifying that we could reproduce our measured results using day-of weather data inputs, we simulated a commonly flown coastal trajectory using five and a half years’ worth of weather balloon data. This trajectory is among the closest currently-flown trajectories to the coast.
The results came back clearly. The seasonal weather causes predictable patterns in where sonic booms are most likely to be heard on land. More specifically, it typically comes down to which direction the upper-level winds (above 10 miles) are blowing, either from the east (summer) or the west (spring/fall). Because these winds change rather predictably throughout the year, we conclude that, for this launch trajectory, sonic booms on land are most likely to be heard in the spring and fall, with somewhat fewer in the winter and very few in the summer. To visualize these trends, Fig. 2 shows representative examples of where the sonic boom will land for each of the four seasons.
Representative sonic boom footprints from each of the four seasons, generated using PCBoom with day-of weather inputs. Actual footprints for a given day are subject to daily weather differences and thus will not exactly match these plots.
With this new understanding of how the seasonal weather affects the sonic boom footprint, we will continue to work with Vandenberg Space Force Base on further rocket ascent sonic boom research. We hope that one day this research will contribute to a world where future rockets can launch regularly while minimizing disruptions to communities and environments.
