Even though timber requires extra material to insulate noise, it can still be more climate-friendly than steel or concrete. #ASA_ASJ2025 #ASA189
HONOLULU, Dec. 3, 2025 — Many modern buildings are “green buildings,” adhering to a complex set of standards to ensure they are environmentally friendly and sustainably designed, with minimal impact on nature and the humans that inhabit them. These standards can govern everything from energy efficiency to construction materials used for acoustic privacy between rooms.
The sheer number of factors to consider when designing such a building can make even veteran architects stumble. Even deciding which construction material to use requires accounting for cost, lifetime carbon emissions, and acoustic performance.
Acoustic consultant George Edgar will present his assessment of various wall and floor types for their climate impact and acoustic performance Wednesday, Dec. 3, 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.
The global warming potential (A1-A3) of two wall systems calculated using INSUL®’s in-development carbon calculation tool. Credit: Marshall Day Acoustics
Sound and noise have a major impact on our ability to focus and communicate, which is why acoustic requirements often feature in green building standards, such as LEED in the U.S. and BREEAM in the U.K.
“The leading voluntary green building schemes in major English-speaking countries and Japan all include credits for acoustics,” said Edgar. “These schemes acknowledge the impact acoustic comfort has on the well-being of a building’s occupants.”
Edgar evaluated multiple materials, including timber, steel, and concrete, for their sound insulating properties along with their global warming potential (GWP), a measure of the carbon emissions involved in manufacturing them.
“The primary factor that influences GWP in the manufacturing phase is the amount of energy, and therefore carbon emissions, required to produce the material,” said Edgar. “Concrete and steel are more energy-intensive to produce than timber products, so they have higher GWP values in the manufacturing phase.”
Edgar found that, for floors with a given sound insulation performance, concrete could have a far higher GWP than timber, and walls that incorporated timber outperformed standard steel studs, even when they needed more wall linings to achieve the same acoustic performance.
Despite the importance of these results, little research has been done examining both the acoustic performance and climate impacts of building materials. Edgar is optimistic that his work will lead to buildings that are both quiet and climate-friendly.
“As acoustic consultants, an awareness of the GWP associated with the design solutions we specify can help us to make a positive impact on our environment for generations to come,” said Edgar. “I’d like to see more research in this area so we can all make more informed decisions when considering acoustics and sustainability.”
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/.
–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–
Motivation
In many cities, people want to keep their windows open to allow fresh air into their homes. However, especially in busy urban areas, open windows also let in unwanted noise from traffic, trains, aircraft, and general city activity. Constant exposure to this noise is not just annoying, it can affect sleep, concentration, and even long-term health. To address this problem, researchers at the Helmut Schmidt University in Hamburg have spent the past fifteen years developing systems that can reduce noise coming through partially open windows while still allowing natural ventilation.
Passive Absorbers
The approach combines two methods: passive noise reduction and active noise control (ANC). Passive noise reduction involves using materials that naturally absorb or block sound, such as foam-like acoustic panels or special seals. These materials are very good at reducing high-frequency noise but are less effective for deeper, low-pitched sounds like engines or traffic rumble.
ActiveNoise Control
This is where active noise control comes in. ANC works in a way similar to noise-cancelling headphones. Small loudspeakers placed near the window play “anti-noise sound waves” that are shaped to cancel out incoming noise. When the incoming noise and the anti-noise meet, they interfere with each other and reduce the amount of sound that reaches inside the room. To make this happen, microphones are used to measure the sound, while computer algorithms constantly adjust the sound from the speakers to keep the cancellation effective.
Figure 1: Internoise 2020, J. Hanselka, D. Sachau, Converting an Active Noise Blocker for a Tilted Window from Feedforward Control into a Feedback System
Algorithm
worked on improving the computer algorithms that run the ANC system. These algorithms need to react quickly to changing noise, remain stable, and avoid using too much power. Therefor analyses conduction different real-time-controller platforms were evaluated, including DSP and FPGA technology
Figure 2: ISMA 2014, D. Sachau, S. Jukkert, Real-time implementation of the frequency-domain FxLMS algorithm without block delay for adaptive noise blocker
Simulation
However, using ANC at an open window is much more complicated than inside headphones. The sound field near an open window is irregular and constantly changing because of airflow, reflections, and outdoor conditions. The research team therefore studied how sound moves through small openings of different shapes and sizes. One important discovery is that the depth of the opening relative to the wavelength of the sound plays a enormous role in how much noise gets through. This knowledge helps guide how the ANC system can be designed and placed.
Figure 3: Internoise2020, M. Sandner, D. Sachau, Influence of parameters of small gaps regarding sound transmission and ANC-performance-a numerical simulation
Position Optimization
Another major research effort focused on the best positions for microphones and speakers. Their placement determines how well the noise can be cancelled. The researchers found that placing the speaker near the center of the opening often provides the most even noise reduction throughout the room. Meanwhile, microphone placement is very important for stability, because the microphone input is what guides the control system in real time.
Figure 4: DAGA 2025, T. Karl, D. Sachau, Numerical position optimization approach for sensor and actuator placement in an active noise cancelling system
Conclusion
Overall, the research shows that a combination of passive materials and active noise control is the best approach. Passive elements reduce parts of the noise that are hard to cancel electronically, while ANC handles the deep, low-frequency noise that humans find especially disturbing. Together, these methods make it possible to keep windows open for fresh air -without letting in the city.
–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: Max Addae 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 (Max Addae) added by Alaa Algargoosh. Right: Max Addae vocalizing in Boston Symphony Hall.
–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–
Western churches typically evoke the impression of long, reverberant echoes. This acoustic quality is largely influenced by their domed ceilings and stone construction, which amplify and sustain sound. A single note from an organ or choir can travel far and linger in the air, creating a bright and grand sound field.
In contrast, Asian temples often have acoustic characteristics that differ significantly from those of Western churches. In particular, traditional Korean temples have a soft and warm sound environment. Their structures are primarily composed of wood, soil, and paper, reflecting Korea’s architectural philosophy of harmony with nature and the surrounding landscape. Instead of a strong, ringing echo, the listener experiences a gentle and intimate atmosphere.
Our study explores the acoustic characteristics of Magoksa Temple in South Korea, a Buddhist temple complex whose main halls date back to the 17th century. We measured the reverberation and other acoustic properties of three main temple halls and analyzed how sound behaves in these wooden spaces. The goal of this study is to understand these unique sound behaviors and to consider how they can be recreated when digitally restoring historical sites in virtual reality content and other media.
Figure 1: Main worship hall (Daegwangbojeon) of Magoksa Temple and surrounding courtyard.
To carry out the measurements, we played test signals through a loudspeaker and recorded the responses using microphones, including a three-dimensional (3D) microphone array. These room impulse responses capture the “acoustic fingerprint” of each hall: how long sound lasts, which frequency bands are emphasized or reduced, and how sound energy arrives from different directions around a listener.
Figure 2: Acoustic measurement setup inside a temple hall with a loudspeaker and 3D microphone array.
We found that all three temple halls share two distinctive features:
Strong low-frequency resonance – Deep sounds, such as drums or low chanting, tend to linger longer than higher-pitched sounds. One important reason is structural: the floors are hollow beneath the wooden planks, and this cavity reinforces low-frequency energy, similar to the body of a musical instrument.
High-frequency absorption – Soft materials such as paper doors, soil walls, and exposed wood absorb much of the high-frequency content. This reduces sharp reflections and makes the space sound calm and close, rather than bright or very echoey like a stone cathedral.
Figure 3: Frequency responses of the three main halls at Magoksa Temple.
Using the 3D microphone array, we also examined spatial characteristics, such as which parts of the structure (floor, ceiling, or side walls) create the most prominent reflections, and how sound surrounds a seated listener. These results help us understand more deeply how traditional Korean temples use their wooden structures and natural materials to create such distinctive acoustics.
Understanding these sound patterns helps us preserve more than just the visual beauty of cultural heritage—it allows us to capture the aural identity of a place. By integrating these findings into digital reconstructions and virtual reality experiences, we can make presentations of traditional Korean architecture feel more realistic and immersive, allowing future generations not only to see history but also to hear it.
NEW ORLEANS, May 23, 2025 – When children are dropped off at a school or day care for the first time, there can be a lot of feelings and sometimes meltdowns caused by being separated from parents, meeting new people, and hearing new noises. Could the architecture of the room help to soothe at least some of the children’s concerns?
“Classrooms without any sound absorption are the majority in Japan,” said Ikuri Matsuoka, a master’s student at Kumamoto University in Japan. “My motivation was to make people aware of the importance of acoustics in classrooms because in Japan, there are no standards or guidelines for acoustic design of preschool and school classrooms.”
Children in the process of developing language and speech can have a hard time listening, and so a classroom with lots of noise and reverberation can disturb communication and cause them to talk louder.
“We expect that preschool children entering school for the first time normally feel stressed by the difficulty of verbal communication,” Matsuoka said. “Therefore, this study examined whether sound absorption could mitigate such adverse effects.”
A classroom in Japan with polyester fiberboard tiles on the ceiling to promote sound absorption. Credit: Ikuri Matsuoka
To test the effect of sound absorption on children’s noise, Matsuoka installed polyester fiberboard, a type of sound-absorbing material, onto one classroom’s ceiling and compared it to another without any.
Matsuoka will present their findings Friday, May 23, at 1:40 p.m. CT as part of the joint 188th Meeting of the Acoustical Society of America and 25th International Congress on Acoustics, running May 18-23.
Matsuoka analyzed the indoor activities using video and audio to determine noise levels and the number of times the children cried. After six months, Matsuoka found that children were louder in the room without the insulation.
“During the experiment, I interviewed the four teachers in the four classes several times,” Matsuoka said. “Three of the four teachers answered that they felt the reverberation had changed, and one of them, a veteran teacher with 25 years of experience, answered that she felt clearly more comfortable talking to the children.”
To complement their results, Matsuoka and their professor also used artificial intelligence and machine learning to analyze the data automatically. They used an acoustic event detection method to identify children’s crying instead of manually scrubbing through the data. This work will also be presented during a session on “Materials for Sound Absorption, Diffusion, and Transmission Loss” on Friday, May 23, at 1:00 p.m. CT.
“We expect that machine learning will be necessary for long-term observations,” Matsuoka said. “From our research, we hope that those involved in both the child care and architectural fields recognize how important it is to have reduced reverberation that mitigate noisy atmosphere and promote clear verbal communication for children.”
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 INTERNATIONAL COMMISSION FOR ACOUSTICS The purpose of the International Commission for Acoustics (ICA) is to promote international development and collaboration in all fields of acoustics including research, development, education, and standardization. ICA’s mission is to be the reference point for the acoustic community, becoming more inclusive and proactive in our global outreach, increasing coordination and support for the growing international interest and activity in acoustics. Learn more at https://www.icacommission.org/.
NEW ORLEANS, May 21, 2025 – Have you ever walked through the ruins of an ancient city and wondered what life sounded like back then? So has Sezin Nas, a researcher of interior architecture and acoustics at Istanbul Galata University.
The ancient, underground city of Derinkuyu caught Nas’s eye early on. Located in modern-day Turkey, Derinkuyu was built underground to defend against invasion, protect its citizens from harsh weather, and safely store agricultural products. At its peak, it could hold up to 20,000 people. The city spanned seven levels underground, with four main ventilation channels and over 50,000 other smaller shafts
“There is a notable gap in the literature regarding the acoustic environment and soundscape of underground cities,” Nas said. “Studying the Derinkuyu underground city aimed to contribute both to the preservation of cultural heritage and to provide data that could inform the design of future underground urban spaces.”
A collection of images from the underground tunnels of Derinkuyu. Credit: Sezin Nas
“The integration of ventilation and communication functions within the same architectural elements is considered one of Derinkuyu’s most unique features,” Nas said. “This multifunctional use of the ventilation system strongly highlights the exceptional construction process of the site and plays a central role in shaping its soundscape.”
To re-create the ancient soundscape, Nas studied both the history of the city as well as its architecture. She analyzed three types of spaces — a church, a living area, and a kitchen. The room functions, sources of sounds, and even reverberations were considered when creating a 3D virtual soundscape that will eventually allow a listener to experience the sounds of the city.
Nas will present work on the soundscape of the ancient city of Derinkuyu on Wednesday, May 21, at 11:20 a.m. CT as part of the joint 188th Meeting of the Acoustical Society of America and 25th International Congress on Acoustics, running May 18-23.
“Derinkuyu underground city is considered an interior environment on an urban scale, which distinguishes it from the open-space urban soundscapes,” Nas said. “Listening to the reconstructed soundscape provides insights into how sound influenced spatial experience, communication practices, and social organization within the underground city.”
Nas said Derinkuyu’s soundscape can inspire the design of future underground urban spaces. She hopes that, in general, soundscapes will be used in the future as systematic tools for studying history.
“This research also highlights the role of historical sound environments as an important and often overlooked component of cultural heritage,” Nas said.
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 INTERNATIONAL COMMISSION FOR ACOUSTICS The purpose of the International Commission for Acoustics (ICA) is to promote international development and collaboration in all fields of acoustics including research, development, education, and standardization. ICA’s mission is to be the reference point for the acoustic community, becoming more inclusive and proactive in our global outreach, increasing coordination and support for the growing international interest and activity in acoustics. Learn more at https://www.icacommission.org/.
Figure 1: Internoise 2020, J. Hanselka, D. Sachau, Converting an Active Noise Blocker for a Tilted Window from Feedforward Control into a Feedback System
Figure 2: ISMA 2014, D. Sachau, S. Jukkert, Real-time implementation of the frequency-domain FxLMS algorithm without block delay for adaptive noise blocker
Figure 3: Internoise2020, M. Sandner, D. Sachau, Influence of parameters of small gaps regarding sound transmission and ANC-performance-a numerical simulation
Figure 4: DAGA 2025, T. Karl, D. Sachau, Numerical position optimization approach for sensor and actuator placement in an active noise cancelling system
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.
Figure 2: Visualization of interacting with different acoustic environments. Left: Max Addae vocalizing in an office environment (MIT Media Lab). Middle: “Hagia Sophia – Muhammad, Allah, Abu Bakr” by Rabe!, licensed under CC BY-SA 3.0 (
Figure 1: Main worship hall (Daegwangbojeon) of Magoksa Temple and surrounding courtyard.
Figure 2: Acoustic measurement setup inside a temple hall with a loudspeaker and 3D microphone array.
Figure 3: Frequency responses of the three main halls at Magoksa Temple.
