Soundscape Research Research Articles

Acceptability and appeal: How visitors’ perceptions of sounds can contribute to shared learning and transdisciplinary protected area governance

This paper demonstrates how protected area (PA) acoustic environments , or soundscapes, can provide a boundary object for transdisciplinary conservation governance, informing and facilitating better communication, transdisciplinary learning, and decision making. Through visitor intercepts and on-site listening exercises (N = 899), research examined the appeal and acceptability of perceived sounds, to understand the congruence between visitors’ ratings for the ten open-coded sound categories that emerged. Discussion presents a hypothetical transdisciplinary governance scenario demonstrating how actors can employ similar research to advance collaborative transdisciplinary conservation learning and governance, through collaborative consideration of emergent trends across sound categories and local, national, and international tourist visitor groups. For example, all participants frequently observed Birds, Forest, and Water sounds, as highly appealing and acceptable. This aligns well with core natural PA attributes and conservation objectives. Wind and Insect sounds were less appealing, particularly for international tourists; yet considered acceptable within the PA, for all groups. Perhaps divergence can be addressed through programming and/or infrastructure. Low acceptability for Machine sounds should concern conservation governance; participants seemingly did not connect machine sounds with important PA conservation practices. • Soundscape research can assist collaborative stakeholder ecological governance and learning. • Research employs soundscape acceptability/appeal measures for transdisciplinary governance. • Assessing congruence in acceptability and appeal helps gauge visitor understanding of PA values. • Better visitor understanding/education around human-nature soundscape relationships is needed.

Baseline soundscapes of deep‐sea habitats reveal heterogeneity among ecosystems and sensitivity to anthropogenic impacts

AbstractUnderwater soundscapes, though invisible, are crucial in shaping the biodiversity of marine ecosystems by acting as habitat‐specific settlement cues for larvae. The deep sea has received little attention in soundscape research, but it is being targeted for mineral extraction to feed the ever‐growing needs of our society. Anthropogenic impacts on soundscapes influence the resilience of key shallow‐water habitats, and the same likely applies to the deep. Japan is a forerunner in deep‐sea mining, but virtually no deep soundscape baselines exist for Japanese waters. Here, we report baseline soundscapes from four deep‐sea locations in Japan, including the Suiyo Seamount hydrothermal vent, the abyssal plain around the Minamitorishima Island home to manganese nodule fields and muds rich in rare‐earth elements, twilight depths off Sanriku, as well as a typical bathyal system in Suruga Bay. Long‐duration audio recordings were visualized and factorized by an unsupervised machine learning model, revealing differing characteristics among the habitats. Two locations near the coast are highly influenced by shipping noise. The Suiyo vent is characterized by low‐frequency sounds from venting, and the abyssal Minamitorishima is quiet with a flat spectral shape. Noise from observation platforms is likely sufficient to alter soundscape characteristics, especially in offshore locations, suggesting offshore mining‐targeted areas are susceptible to impacts from anthropogenic noise. We argue that the monitoring of soundscapes is an indispensable component for assessing potential mining impacts on deep‐sea ecosystems. Our results establish reference points for future soundscape monitoring and assessment in Japanese waters as well as similar ecosystems globally.

The effects of aural and visual factors on appropriateness ratings of residential spaces in an urban city.

This study investigates the aural and visual factors that influence appropriateness perception in soundscape evaluations in residential spaces, where people may spend most of their time in. Appropriateness in soundscape is derived from the expectation of sound sources in a specific environment, place or function heard by a listener. Appropriateness of soundscapes in 30 locations in an urban residential environment is investigated with varying landscape, visual and aural elements through a questionnaire. Participants experienced the soundscape in-situ and were asked to evaluate the appropriateness of soundscape as well as the dominance of specific sound sources such as traffic, human activities and birdsongs in the residential space. The effect of type of traffic on appropriateness is also investigated. A strong relationship is found between appropriateness and affective soundscape qualities such as pleasantness, highlighting the importance of considering appropriateness in soundscape research. In audio-visual combination of specific elements and the partial correlation with appropriateness, specific aural sound sources are found to correlate uniquely to appropriateness while controlling for relevant visual elements, whereas visual elements became redundant in its partial correlation to appropriateness. Residents' perception of appropriateness is found to likely be more dependent on the individual visual elements rather than the overall landscape. This study investigates the factors that influences appropriateness perceptual in soundscape evaluations in residential spaces, where people may spend most of their time in. Appropriateness in soundscape is derived from the expectation of sound sources in a specific environment, place or function and heard by a listener. The appropriateness of soundscapes of 30 locations in an urban residential environment is investigated with varying visual (greenery, building, waterbody) and aural elements through a questionnaire approach. Participants experienced the soundscape in-situ and were asked to evaluate the appropriateness of soundscape as well as the dominance of specific sound sources such as traffic, human activities and birdsongs in a residential space. The type of traffic is also investigated to explore the effect of traffic load on appropriateness.

Understanding the Effect of Restorativeness in Indoor Soundscapes through a Conceptual Model

The soundscape is defined as the acoustic environment perceived or experienced by a person or people. Soundscape research, where human perception is at the center, has generally been conducted on unwanted sound sources to identify sounds' negative health effects. Therefore, wanted sound sources and their impact on being exposed to soundscapes that may induce positive outputs on health has been neglected. People tend to be in places that reduce stress and increase restoration. However, many indoor places cause stress in our daily lives and decrease the quality of living. This study aims to generate the conceptual model that would be used to identify what causes stress indoors and what can be done to transfer these spaces into restorative ones from the soundscape perspective. To generate a comprehensive model, by centering the soundscape framework of ISO, its constructs were combined with Attention Restorative Theory (ART), Stress Recovery Theory (SRT), and Biophilic Design approach into positive and negative relations based on their effects on health.

Environmental sound as a mirror of landscape ecological integrity in monitoring programs

Soundscape research has acquired a paramount role in biodiversity conservation as it may provide timely and reliable information about the ecological integrity. The relationship between soundscape complexity and ecological integrity in highly biodiverse environments, as well as the factors affecting this relationship require a thorough understanding. We determined how the soundscape relates to the landscape ecological integrity at different spatial and temporal scales in a montane forest in the northern Andes of Colombia. Between May–July 2018 we obtained acoustic recordings from 31 sampling sites in the protected area of a hydropower plant, and estimated nine acoustic indices and an ecological integrity index (EII) derived from fragmentation, connectivity, and habitat quality. Five of the acoustic indices, linked to the evenness of the acoustic signals and levels of the biophonic signals, were associated with changes in the EII and indicated the presence of more even, saturated, and acoustically rich soundscapes in sites with higher integrity. Relationships between acoustic indices and the EII were stronger at a smaller spatial scale (100 m) and responded to daily variation of the soundscape, with the strongest associations occurring mainly from sunrise to noon. We show that acoustic indices measuring the evenness of the acoustic activity distribution and the number of frequency peaks reliably reflect the changes in the ecological integrity, and can be integrated with remote sensing as a tool for landscape management. Our results highlight the soundscape analysis as a feasible approach for the monitoring and conservation planning of acoustically unknown and threatened Andean landscapes.

Flow in soundscape: the conceptualization of soundscape flow experience and its relationship with soundscape perception and behaviour intention in tourism destinations

ABSTRACT The soundscape is an essential type of attraction in tourism destinations. Music can serve as a significant tourist attraction that makes people immersed in it. Similarly, while tourists linger in the leisure and recreation environment, they may have a flow experience of the soundscape in tourism attractions. Yet, there is little research about the relationship between tourists’ perception of soundscape and flow experience. Taking Lijiang old town, a world heritage site, as an example, this study explored the dimensions of tourists’ perception of soundscape and soundscape flow experience and examined the influence of soundscape perception on soundscape flow experience. The results indicate that soundscape perception includes three dimensions: preference, comfort, and richness. The flow experience of soundscape is a second-order construct in this research, which contains four dimensions: time distortion, control, enjoyment, and concentration. Besides, preference and richness positively influence flow experience, and flow experience contributes to behavioural intention, whereas comfort does not significantly affect flow experience. This study applied flow theory to soundscape research, which enriches the study of soundscape experience. This study has also provided management strategies for tourism destinations to improve the quality of the soundscape experience.

Recognition of sound source components in soundscape based on deep learning

Sound source components are a crucially important aspect in soundscape, since humans’ perception and evaluation of soundscape strongly depend on the recognition of the constituent sound sources of the acoustic environment. Over the last few years, numbers of studies examined the methods of automated recognition of environmental sound sources/events using machine learning technology. However, the recognition of sound source components in soundscapes remains a challenge for real applications. This present study utilizes the deep learning, a latest developed and advanced machine learning technology, to develop an algorithm to solve this challenge. Without manually extracted acoustic or psychoacoustic features based on expertise, this algorithm automatically extracts features from the spectrogram representation of the sound signals and makes the recognition. It produces the sound source components recognized in the acoustic environment and their respective present time. The algorithm achieves high recognition accuracy, based on binaural recordings of outdoor acoustic environment. For new recordings, i.e., test samples, the recognition accuracies vary from 81.3% to 100%, depending on the specific sound source. This algorithm developed can greatly help soundscape research, and can be applied in automatic soundscape description of sound source components, prediction of soundscape perception and evaluation, and soundscape management.

Acoustic research at the National University of Singapore

Noise pollution is a major problem in many major cities in particular a small island state like Singapore with residential buildings very close to the major trunk roads and expressways. There are therefore increased interest in designs and solutions that will contribute to better sonic ambience. In this presentation, I will focus on the recent research and investigation in related to sonic crystals, acoustic metamaterials, noise barriers, and soundscape. The focus on sonic crystal research is on the use of sonic crystals in the form of sonic windows and sonic cage that would provide noise mitigation in addition to natural ventilation and day light. The design would also include the incorporation of Helmholtz’s resonators, labyrinth and micro-perforated features into the sonic crystal structures. The focus on acoustic metamaterials would be on ventilated acoustic meta-structures incorporating Helmholtz’s resonators and labyrinth or coiled-up space features. For soundscape research, a novel calibration method has been put forward for making the typical smartphone to be accurate enough as a sound level meter for the measurement of environmental noise. Some studies in terms of cabin noise of subway systems, aircraft cabins, high speed trains would be presented.

Audio-visual interactions enhance soundscape perception in China’s protected areas

Coordination of sound and view management is essential to construct tranquility and enhance the visitor experience in protected areas. However, research on audio-visual interactions has historically primarily focused on urban environments, revealing a significant gap in protected areas. In China, soundscape research is urgently needed in protected areas to preserve the long tradition of soundscape appreciation and the high social and ecological values of soundscapes under overwhelming tourism pressure. Using the Wulingyuan World Heritage Site as the case study and through the lens of ten semantic differentials (SDs), this article employed a lab experiment to explore the influence of audio-visual interactions on soundscape assessment to inform the management of protected areas. Our results show that, regardless of the soundscape composition (i.e., primarily natural vs. mixed vs. anthropogenic), the two types of visual stimuli tested, which either matches or mismatches the sound sampling sites, generally led to higher soundscape assessment than when no visual stimuli were present. This positive effect of audio-visual interaction on soundscape assessment, however, would potentially be offset by the adverse visual impacts of overly artificial non-matching scenes. The nature of the sound, characteristics of the visual stimuli, and the personality dimension of extraversion were significantly associated with soundscape assessment. Different SDs exhibited varied influences from visual vs. audio stimuli. In particular, irritating/happy and ugly/beautiful showed the highest sensitivity to visual stimuli, whereas artificial/natural was mainly determined by the sound characteristics.These results call for multi-scale landscape interventions to address the increasingly prevalent low audio-visual congruence in China’s protected areas. Identifying critical mismatches between the visual and audio environment and developing coordinated management strategies will be essential to preserving the tranquility of protected areas and improving public perception.

Estimating the Economic Value of Soundscapes in Nature-Based Tourism Destinations: A Separation Attempt of a Pairwise Comparison Method

Recent soundscape research is notable owing to the increasing demand for “multisensory” tourism experiences. However, the traditional economic value assessment of tourism destinations mostly takes each type of landscape as a whole for measurement, and it has been challenging to separate the soundscape from the whole landscape. Therefore, research on the economic value of soundscapes is still lacking. This study chose the characteristic soundscape of the Qiantang River tide as the research object, and tried to apply the pairwise comparison method to calculate the separation coefficient of the soundscape from the overall landscape. The results showed that the separation coefficient of the soundscape was 0.138 and the economic value of the Qiantang River tide soundscape was between CNY 315.145 million (USD 48.7 million) and CNY 333.841 million CNY (USD 51.6 million). Finally, we discuss the effectiveness of the separation methods, the differences in willingness to pay between the interviewees, and the sustainable use of the natural soundscape resources in tourism destinations.

Transient soundscape production

Over the past decade, there has been a steady increase of scholarly output examining the multidisciplinary, creative, and theoretical aspects of sound and music production in the recording studio and beyond (Zagorski-Thomas & Bourbon, 2020; Bennett & Bates, 2019; Hepworth- Sawyer, Hodgson, & Marrington, 2019; Thompson, 2019; Zagorski-Thomas, 2014; Frith & Zagorski-Thomas, 2012). Accordingly, a broad range of literature examines sound as a widespread cultural phenomenon (Papenburg & Schulze, 2016) and an essential source for pedagogical and ethnographic modeling in music technology education (Bell, 2018). Advances in technology make the “studio,” long viewed as a site of artistic and commercial production, available to a broader group of composers, musicians, and artists. Similarly, portable digital recorders afford sound artists and fi eld recordists an expansive range of choices to conduct soundscape research and creative practice. What emerges is a hybrid “composer- producer” identity and a studio’s function in the artistic process. This growth is the rise of an independent and transient practice in soundscape production among multidisciplinary composers and musicians. This article advocates for an updated notion of soundscape composition that integrates fi eld recordings, studio production, and collaboration from musicians representing a broad range of stylistic infl uences. Positioning the studio as a site of cultural production and creativity has implications for how soundscape production is taught to young composers. The author argues for a more inclusive, process-oriented view on both creativity and the places where musicians, composers, and producers work. The article includes a case study from the author’s recent album project, narrative analysis, concluding with a discussion on the pedagogical implications of independent soundscape production in education.

The “sound of silence” in Granada during the COVID-19 lockdown

Abstract Exceptional circumstances in the city of Granada due to the COVID-19 lockdown have provided the opportunity to characterise the impact of humans on its urban acoustic climate. Traditional environmental noise management and urban sound planning usually take into account noise sources in the city, such as industrial activities or road traffic noise, in model estimations, as well as in empirical research. But trying to isolate human impact by itself, human activity including social activity, walking, talking or just going around the city, has always been a difficult or even impossible task. The COVID-19 lockdown measures have provided the opportunity to study urban climate as never before, affected just by natural or animal noise sources. Previous soundscape research at some iconic sites in the city of Granada carried out in 2019 before the lockdown and a special measuring campaign carried out at the same locations during the lockdown in 2020 offered valuable information on sound levels and local characteristics in order to carry out this comparison. Results show a great change in environmental noise levels that is interesting not only because of its magnitude, but also for its implications, especially at those sites where social human activity was an identifying characteristic. Natural or animal sounds became surprisingly evident at some study sites, especially where road traffic noise dramatically decreased, leading to significantly lower background noise levels. Important spectral changes are observed before and during the lockdown, suggesting a shift from anthropic to animal sources in the acoustic environment.

Ecological Validity of Immersive Virtual Reality (IVR) Techniques for the Perception of Urban Sound Environments

Immersive Virtual Reality (IVR) is a simulated technology used to deliver multisensory information to people under different environmental conditions. When IVR is generally applied in urban planning and soundscape research, it reveals attractive possibilities for the assessment of urban sound environments with higher immersion for human participation. In virtual sound environments, various topics and measures are designed to collect subjective responses from participants under simulated laboratory conditions. Soundscape or noise assessment studies during virtual experiences adopt an evaluation approach similar to in situ methods. This paper aims to review the approaches that are utilized to assess the ecological validity of IVR for the perception of urban sound environments and the necessary technologies during audio–visual reproduction to establish a dynamic IVR experience that ensures ecological validity. The review shows that, through the use of laboratory tests including subjective response surveys, cognitive performance tests and physiological responses, the ecological validity of IVR can be assessed for the perception of urban sound environments. The reproduction system with head-tracking functions synchronizing spatial audio and visual stimuli (e.g., head-mounted displays (HMDs) with first-order Ambisonics (FOA)-tracked binaural playback) represents the prevailing trend to achieve high ecological validity. These studies potentially contribute to the outcomes of a normalized evaluation framework for subjective soundscape and noise assessments in virtual environments.

Investigating contextual influences on urban soundscape evaluations with structural equation modeling

Previous soundscape research has shown a complex relationship between soundscapes, public space usage and contexts of users’ visits to the space. Yet many of these findings are restricted to one study site at a time and may not generalize to a global understanding of urban sound environments. The present study is a comparative analysis of in situ questionnaires collected over four study sites in Montreal (N = 1429) in both French and English. At each site, the questionnaire included items from the Swedish Soundscape Quality Protocol and other soundscape variables, as well as person-related (age, gender, extraversion, noise sensitivity) and situation-related (social interaction) variables. We first tested measurement invariance between the French and English versions of the used soundscape questionnaire. We then investigated the influence of contextual factors (combining person-related and situation-related variables) on soundscape evaluations. The analyses confirmed the underlying conceptualizations of proposed soundscape assessment questionnaires, confirmed metric invariance between French and English questionnaires, and revealed significant influences of contextual factors on soundscape dimensions. Our analysis further suggests that younger people, women, and extraverted people occupy the public space more in groups, and that people in groups rate the soundscape as more pleasant and less eventful. Older people and women were found to be more sensitive to noise, and more sensitive people tended to perceive the soundscape as less pleasant and less monotonous. This research represents a critical step in rigorously assessing soundscape evaluation methods and establishes solid groundwork to build more complex models of contextual influences on soundscape evaluation.

Assessments of Acoustic Environments by Emotions - The Application of Emotion Theory in Soundscape.

Human beings respond to their immediate environments in a variety of ways, with emotion playing a cardinal role. In evolutionary theories, emotions are thought to prepare an organism for action. The interplay of acoustic environments, emotions, and evolutionary needs are currently subject to discussion in soundscape research. Universal definitions of emotion and its nature are currently missing, but there seems to be a fundamental consensus that emotions are internal, evanescent, mostly conscious, relational, manifest in different forms, and serve a purpose. Research in this area is expanding, particularly in regards to the context-related, affective, and emotional processing of environmental stimuli. A number of studies present ways to determine the nature of emotions elicited by a soundscape and to measure these reliably. Yet the crucial question—which basic and complex emotions are triggered and how they relate to affective appraisal—has still not been conclusively answered. To help frame research on this topic, an overview of the theoretical background is presented that applies emotion theory to soundscape. Two latent fundamental dimensions are often found at the center of theoretical concepts of emotion: valence and arousal. These established universal dimensions can also be applied in the context of emotions that are elicited by soundscapes. Another, and perhaps more familiar, parallel is found between emotion and music. However, acoustic environments are more subtle than musical arrangements, rarely applying the compositional and artistic considerations frequently used in music. That said, the measurement of emotion in the context of soundscape studies is only of additional value if some fundamental inquiries are sufficiently answered: To what extent does the reporting act itself alter emotional responses? Are all important affective qualities consciously accessible and directly measurable by self-reports? How can emotion related to the environment be separated from affective predisposition? By means of a conceptual analysis of relevant soundscape publications, the consensus and conflicts on these fundamental questions in the light of soundscape theory are highlighted and needed research actions are framed. The overview closes with a proposed modification to an existing, standardized framework to include the meaning of emotion in the design of soundscapes.

Modeling Evaluations of Low-Level Sounds in Everyday Situations Using Linear Machine Learning for Variable Selection.

Human sound evaluations not only depend on the characteristics of the sound but are also driven by factors related to the listener and the situation. Our research aimed to investigate crucial factors influencing the perception of low-level sounds as they—in addition to the often-researched loud-level sounds—might be decisive to people’s quality of life and health. We conducted an online study in which 1,301 participants reported on up to three everyday situations in which they perceived low-level sounds, resulting in a total of 2,800 listening situations. Participants rated the sounds’ perceived loudness, timbre, and tonality. Additionally, they described the listening situations employing situational eight dimensions and reported their affective states. All sounds were then assigned to the categories natural, human, and technical. Linear models suggest a significant difference of annoyance ratings across sound categories for binary loudness levels. The ability to mentally fade-out sound was the most crucial situational variable after valence, arousal, and the situation dimensions positivity and negativity. We ultimately selected the most important factors from a large number of independent variables by applying the percentile least absolute shrinkage and selection operator (Lasso) regularization method. The resulting linear regression showed that this novel machine-learning variable-selection technique is applicable in hypothesis testing of noise effects and soundscape research. The typical problems of overfitting and multicollinearity that occur when many situational and personal variables are involved were overcome. This study provides an extensive database of evaluated everyday sounds and listening situations, offering an enormous test power. Our machine learning approach, whose application leads to comprehensive models for the prediction of sound perception, is available for future study designs aiming to model sound perception and evaluation.

Acoustics for Supportive and Healthy Buildings: Emerging Themes on Indoor Soundscape Research

The focus of the building industry and research is shifting from delivering satisfactory spaces to going beyond what is merely acceptable with a wave of new research and practice dedicated to exploring how the built environment can support task performance and enhance people’s health and well-being. The present study addresses the role of acoustics in this paradigm shift. Indoor soundscape research has recently emerged as an approach that brings a perceptual perspective on building and room acoustics in order to shape built environments that “sound good” according to building occupants’ preference and needs. This paper establishes an initial discussion over some of the open questions in this field of research that is still in an embryonic stage. A thematic analysis of structured interviews with a panel of experts offered a range of perspectives on the characterization, management, and design of indoor soundscapes and health-related outcomes. The discussion pointed out the importance of both perceptual and multisensory research and integrated participatory design practices to enable a holistic view regarding the complex building–user interrelations and the design of just cities. Soundscape methodologies tailored to the peculiarities of indoor soundscapes can help to measure and predict the human perceptual response to the acoustic stimuli in context, thus reducing the risk of mismatches between expected and real building experiences. This perceptual perspective is expected to widen the scientific evidence for the negative and positive impacts of the acoustic environment on human health, well-being, and quality of life. This will support prioritizing the role of acoustics in building design and challenge many current design practices that are based on a noise control approach.

Valuing transport noise impacts in public urban spaces in the UK: Gaps, opportunities and challenges

Transport noise is the dominant noise source in urban areas. Its impacts on people at their residential locations are included in economic appraisal in the UK and many other countries, and guidance and analysis tools were developed for the valuation of the impacts. However, for transport noise impacts on people in public urban spaces, e.g., urban streets, squares and parks, there is still a lack of national methodologies. This paper will discuss the gaps, opportunities and challenges in developing a national methodology for these places in the UK. Currently, evidence is lacking on pathways of transport noise impact on people and dose–response relationships at non-residential locations, and the values people place on sound environment quality at these locations. However, opportunities are emerging, with increasing attention to the urban realm in UK transport policy, and recent progress and transitions in urban sound environment research, including association between public health and urban soundscape, standardisation in soundscape research and practice, and crowdsourcing sound environment evaluations. The associated challenges, as compared to methodology for residential locations, may include calculating noise from non-free-flow traffic, defining and adding diverse receptor types, estimating dynamic affected population, accounting for diversity in level and source of background sound, and obtaining large and consistent data for dose–response or willingness-to-pay analyses.

A review of audio-visual interaction on soundscape assessment in urban built environments

The sense of sight or ‘visual’ plays a crucial role in the perception of soundscape. Since the concept of soundscape is put forward, audio-visual interaction has been incorporated in soundscape research, particularly in urban planning and noise control. The study on audio-visual interactions have not only enhanced and expanded the contents of soundscape assessment, but also helped to develop more comprehensive approaches for the recording and reproduction of audio-visual signals. This paper aims to evaluate the effects of audio-visual interactions on soundscape assessment and noise control through an extensive review of existing literatures. Methodologies of in situ surveys and laboratory experiments are summarized and discussed, which allows a classification system and conceptual framework for soundscape study and design with audio-visual interaction to be constructed. Accordingly, this framework can provide a guideline for the methodologies to be used in future audio-visual assessments of soundscapes and blueprint for how an audio-visual experiment should be designed.

Noise acceptance of acoustic sequences for indoor soundscape in transport hubs.

Noise acceptance is an aspect of indoor soundscape research. While staying or walking in a transport hub, sequential sounds form sequence sounds sessions, which are referred to as an acoustic sequence. The basic phenomenon and effects of acoustic sequences on acceptance evaluations have been explored. A total of 209 sections of 30 s acoustic units were extracted before performing acceptance evaluations. The acoustic units were divided into strong, medium, and weak levels, and compiled into 37 pieces of acoustic sequences, which were then subjected to four tests for acceptance evaluation: sound content, acceptance level, and effects of weak and strong acceptance units. One piece of an acoustic sequence consists of 20 acoustic units. The results show that all acoustic sequences exhibit "attenuation effects"-as for any acoustic unit that makes up the sequence, general acceptance decreases with time. The lower the acceptance, the faster the decay in score. High acceptance units have an "enhancement effect," and the acceptance increases after a high acceptance unit. Low acceptance units have a "boost effect," and the acceptance increases after a low-level acceptance. Both enhancement and boost effects could improve the acceptance evaluation of acoustic sequences and sound experiences in transport hubs.