Our acoustic environment is a critical part of our everyday experience; it is often unconsciously processed with all other stimuli to form an impression of a place and time, but its impact is not always fully understood. Soundscape is a method of assessing the acoustic environment where perception is prioritized. The soundscape method and the soundwalk tool integrate measurements of the human perception of sound with other observations that characterize the environment, such as the sound levels, the type of location and the various sound sources. The combination of these perceptual measurements with other observations helps us to understand how the acoustic environment impacts the people there and can provide directions for possible changes that can improve their quality of life.
The soundscape method suggests assessing all sounds which occur in an environment using collected data related to human perception, the physical acoustic setting, and context. Context includes visual cues, geographic, social, psychological and cultural aspects, including one’s mental image or memory of a place. Soundscape transcends the common studies of noise and sound levels, and is a powerful tool for effecting positive results with regard to the quality of life for stakeholders in the acoustic environment; standardized methodology has been developed that can be adapted to various applications, using sound as a resource. Soundwalks are an important part of the soundscape method and are a useful way to engage stakeholders who participate by consciously observing and evaluating the soundscape.
A soundwalk is an element of the soundscape method that typically will include a walking tour of observation locations over a predetermined route to solicit perceptual feedback from the participants regarding the acoustic environment (see Figures 1 and 2). The participants of the soundwalk typically include stakeholders or “local experts”: members of the community that experience the soundscape daily, users/patrons of a space, residents, business people, and local officials. Soundwalks can be performed from urban areas to wilderness settings, indoors and outdoors; the information collected can have many applications including ordinances and planning, preservation or improvement of the acoustic environment, and building public/self-awareness of the acoustic environment.
The perceptual information collected during a soundwalk includes the sounds heard by the participants and often directed questions with scaled answers; this along with objective sound level measurements and audio recordings can be used to assess an acoustic space(s) in an effort to effect the purpose of the soundwalk. (see Figures 3 and 4) In some cases, the participants are interviewed to get a deeper understanding of their responses or the data can be taken to a lab for further study.
The soundwalk and post processing of collected information is flexible relative to soundscape standard methods to target an acoustic space and purpose of the investigation. This makes it an adaptable and powerful tool for assessing an acoustic environment and improving the quality of life for the those that live in or use that environment, using their own perceptions and feedback.
Have you ever wondered how a museum’s subtle backdrop of sound affects your experience? Are you drawn to the tranquility of silence, the ambiance of exhibition-congruent sounds, or perhaps the hum of people chatting and footsteps echoing through the halls?
Museums increasingly realize that acoustics are crucial in shaping a visitor’s experience. There are acoustic challenges in museum environments, such as finding the right balance between speech intelligibility and privacy, particularly in spaces with open-plan exhibition halls, coupled rooms, high volumes, and highly reflective surfaces.
Addressing the Challenge
Our proposal focuses on using sound masking systems to tackle these challenges. Sound masking is a proven and widely used technique in diverse settings, from offices to public spaces. Conventionally, it involves introducing low-level broadband noise to mask or diminish unwanted sounds, reducing distractions.
Context is Key
In recognizing the pivotal role of context in shaping human perception, strategically integrating sounds as design elements emerges as a powerful tool for enhancing visitor experiences. In line with this, we propose using sounds congruent with the museum environment more effectively than conventional masking sounds like low-level broadband noise. This approach reduces background noise distractions and enhances artwork engagement, creating a more immersive and comprehensive museum experience.
Evaluating the Effects: The Cognitive Immersive Room (CIR)
We assessed these effects using the Cognitive Immersive Room at Rensselaer Polytechnic Institute. This cutting-edge space features a 360° visual display and an eight-channel loudspeaker system for spatial audio rendering. We projected panoramic photographs and ambisonic audio recordings from 16 exhibitions across five relevant museums — MASS MoCA, New York State Museum, Williams College Museum of Art, UAlbany Art Museum, and Hessel Museum of Art.
The Study Setup
Each participant experienced four soundscape scenarios: the original recorded soundscape in each exhibition, the recorded soundscape combined with a conventional sound masker, the recorded soundscape combined with a congruent sound masker, and “silence” which does not involve any recording, comprising the ambient room noise of 41 dB. Figure 1 shows one of the displays used in the experiment and below the presented sound stimulus.
Figure1: Birds of New York exhibition – New York State Museum. The author took the photo with the permission of the museum’s Director of Exhibitions.
Scenario 1: originally recorded soundscape in situ. Scenario 2: recorded soundscape combined with a conventional sound masker. Scenario 3: the recorded soundscape combined with a congruent sound masker.
After each sound stimulus, they responded to a questionnaire. It was applied through a program developed for this research where participants could interact and answer the questions using an iPad. After experiencing the four soundscapes, a final question was asked regarding the participants’ soundscape preference within the exhibition context. Figure 2 shows the experiment design.
The statistically significant results showed a clear preference for congruent sounds, significantly reducing distractions, enhancing focus, and fostering comprehensive and immersive experiences. A majority of 58% of participants preferred the congruent sound scenario, followed by silence at 20%, original soundscape at 14%, and conventional maskers at 8%.
Unknown fish species are singing in large aggregations along almost the entire southern Australian continental shelf on a daily basis, yet we still have little idea of what species these fish are or what this means to them. These singing aggregations are known as fish choruses, they occur when many individuals call continuously for a prolonged period, producing a cacophony of sound that can be detected kilometres away. It is difficult to identify fish species that chorus in offshore marine environments. The current scientific understanding of the sound-producing abilities of all fish species is limited and offshore marine environments are challenging to access. This project aimed to undertake a pilot study which attempted to identify the source species of three fish chorus types (shown below) detected along the southern Australian continental shelf off Bremer Bay in Western Australia from previously collected acoustic recordings.
Each fish chorus type occurred over the hours of sunset, dominating the soundscape within unique frequency bands. Have a listen to the audio file below to get a feeling for how noisy the waters off Bremer Bay become as the sun goes down and the fish start singing. The activity of each fish chorus type changed over time, indicating seasonality in presence and intensity. Chorus I and II demonstrated a peak in calling presence and intensity over late winter to early summer, while Chorus III demonstrated peak calling over late winter to late spring. This informed the sampling methodology of the pilot study, and in December 2019, underwater acoustic recorders and unbaited video recorders were deployed simultaneously on the seafloor along the continental shelf off Bremer Bay to attempt to collect evidence of any large aggregations of fish species present during the production of the fish choruses. Chorus I and the start of Chorus II were detected on the acoustic recordings, corresponding with video recordings of large aggregations of Red Snapper (Centroberyx gerrardi) and Deep Sea Perch (Nemadactylus macropterus). A spectrogram of the acoustic recordings and snapshots from the corresponding underwater video recordings are shown below.
The presence of large aggregations of Red Snapper present while Chorus I was also present was of particular interest to the authors. Previous dissections of this species had revealed that Red Snapper possessed anatomical features that could support sound production through the vibration of their swimbladder using specialised muscles. To explore this further, computerized tomography (CT) scans of several Red Snapper specimens were undertaken. We are currently undertaking 3D modelling of the sound-producing mechanisms of this species to compute the resonance frequency of the fish to better understand if this species could be producing Chorus I.
Listening to fish choruses can tell us about where these fish live, what habitats they use, their spawning behaviour, their feeding behaviour, can indicate their biodiversity, and in certain circumstances, can determine the local abundance of a fish population. For this information to be applied to marine spatial planning and fish species management, it is necessary to identify which fish species are producing these choruses. This pilot study was the first step in an attempt to develop an effective methodology that could be used to address the challenging task of identifying the source species of fish choruses present in offshore environments. We recommend that future studies take an integrated approach to species identification, including the use of arrays of hydrophones paired with underwater video recorders.
Picture a typical evening in the heart of a bustling city: pubs and bars come alive, echoing with laughter, music, and the clink of glasses. These hubs of social life create a vibrant tapestry of sounds. But what happens when this symphony overshadows the tranquility of those living just around the corner?
Image courtesy of Kvikoo, Singapore
Our journey begins in the lively interiors of these establishments. In countries rich in nightlife, you’ll find a high concentration of pubs and bars – sometimes up to 150 per 100,000 people. Inside a pub in Hong Kong, for instance, noise levels can soar to 80 decibels during peak hours, akin to the din of city traffic. Even during ‘happy hours,’ the decibel count hovers around 75, still significant.
But let’s step outside these walls. Here, the story takes a different turn. In residential areas adjacent to these nightspots, the evening air is often filled with an unintended soundtrack: the persistent hum of nightlife. In a study from Macedonia, for instance, residents experienced noise levels of about 67 decibels in the evening – a consistent background murmur disrupting the peace of homes.
This issue isn’t just about sound; it’s about the voices of those affected. Residents’ complaints about noise pollution have become a chorus in many parts of the world, including the United Kingdom, Hong Kong, and Australia. These complaints highlight a pressing question: How can we maintain the lively spirit of our cities while respecting the need for quiet?
Governments and communities are tuning into this challenge. Their responses, colored by cultural and historical factors, range from strict regulations to innovative solutions. For example, in Hong Kong, efforts to control noise at its source, as detailed in a government booklet, showcase one way of striking a balance.
This is a story of harmony – finding a middle ground where the joyous buzz of pubs and bars coexists with the serene rhythm of residential life. It’s about understanding that in the symphony of city life, every note, from the loudest cheer to the softest whisper, plays a crucial role.
NUWC Division Newport, NAVSEA, Newport, RI, 02841, United States
Dr. Lauren A. Freeman, Dr. Daniel Duane, Dr. Ian Rooney from NUWC Division Newport and
Dr. Simon E. Freeman from ARPA-E
Popular version of 1aAB1 – Passive Acoustic Monitoring of Biological Soundscapes in a Changing Climate
Presented at the 184 ASA Meeting
Read the abstract at https://doi.org/10.1121/10.0018023
Climate change is impacting our oceans and marine ecosystems across the globe. Passive acoustic monitoring of marine ecosystems has been shown to provide a window into the heartbeat of an ecosystem, its relative health, and even information such as how many whales or fish are present in a given day or month. By studying marine soundscapes, we collate all of the ambient noise at an underwater location and attribute parts of the soundscape to wind and waves, to boats, and to different types of biology. Long term biological soundscape studies allow us to track changes in ecosystems with a single, small, instrument called a hydrophone. I’ve been studying coral reef soundscapes for nearly a decade now, and am starting to have time series long enough to begin to see how climate change affects soundscapes. Some of the most immediate and pronounced impacts of climate change on shallow ocean soundscapes are evident in varying levels of ambient biological sound. We found a ubiquitous trend at research sites in both the tropical Pacific (Hawaii) and sub-tropical Atlantic (Bermuda) that warmer water tends to be associated with higher ambient noise levels. Different frequency bands provide information about different ecological processes (such as fish calls, invertebrate activity, and algal photosynthesis). The response of each of these processes to temperature changes is not uniform, however each type of ambient noise increases in warmer water. At some point, ocean warming and acidification will fundamentally change the ecological structure of a shallow water environment. This would also be reflected in a fundamentally different soundscape, as described by peak frequencies and sound intensity. While I have not monitored the phase shift of an ecosystem at a single site, I have documented and shown that healthy coral reefs with high levels of parrotfish and reef fish have fundamentally different soundscapes, as reflected in their acoustic signature at different frequency bands, than coral reefs that are degraded and overgrown with fleshy macroalgae. This suggests that long term soundscape monitoring could also track these ecological phase shifts under climate stress and other impacts to marine ecosystems such as overfishing.
A healthy coral reef research site in Hawaii with vibrant corals, many reef fish, and copious nooks and crannies for marine invertebrates to make their homes.
Soundscape segmented into three frequency bands capturing fish vocalizations (blue), parrotfish scrapes (red), and invertebrate clicks along with algal photosynthesis bubbles (yellow). All features show an increase in ambient noise level (PSD, y-axis) with increasing ocean temperature at each site studied in Hawaii.