Acoustic, Visual and Spatial Indicators for the Description of the Soundscape of Waterfront Areas with and without Road Traffic Flow

The interactive effects of traffic sound and window views on indoor soundscape perceptions in the residential area

Environmental noise has long been considered one of the unwelcome aspects of urban life at home. An increasing number of scholars have studied improving indoor acoustic comfort by using the soundscape approach. However, much uncertainty still exists about the relationship between the audio-visual environment and indoor soundscape perception. The current study investigates the interaction effects of traffic sound and window views on indoor soundscape perceptions in residential contexts. Thirty-two participants were presented with 51 scenarios (a combination of 17 window views and three aural stimuli) and requested to assess their soundscape perceptions in a VR experiment. Results showed that traffic noise could moderate the impact of nature, road, and building views on pleasantness, while it can also moderate the effect of water sound and road view on eventfulness. In particular, natural window views were found not to lead to a more pleasant indoor soundscape necessarily; natural window views even decrease the pleasantness of indoor soundscape in the case of heavy traffic noise outside the window. Besides, overall visual indicators, including complexity and openness, have an interactive effect with traffic sound on pleasantness. Last, pleasantness is found to be associated with the appropriateness of indoor soundscape.

The Acoustic Environment and University Students' Satisfaction with the Online Education Method during the COVID-19 Lockdown

The acoustic environment has been pointed out as a possible distractor during student activities in the online academic modality; however, it has not been specifically studied, nor has it been studied in relation to parameters frequently used in academic-quality evaluations. The objective of this study is to characterize the acoustic environment and relate it to students' satisfaction with the online learning modality. For that, three artificial neural networks were calculated, using as target variables the students' satisfaction and the noise interference with autonomous and synchronous activities, using acoustic variables as predictors. The data were obtained during the COVID-19 lockdown, through an online survey addressed to the students of the Universidad de Las Américas (Quito, Ecuador). Results show that the noise interference with comprehensive reading or with making exams and that the frequency of noises, which made the students lose track of the lesson, were relevant factors for students' satisfaction. The perceived loudness also had a remarkable influence on engaging in autonomous and synchronous activities. The performance of the models on students' satisfaction and on the noise interference with autonomous and synchronous activities was satisfactory given that it was built only with acoustic variables, with correlation coefficients of 0.567, 0.853, and 0.865, respectively.

What Constitutes the High-Quality Soundscape in Human Habitats? Utilizing a Random Forest Model to Explore Soundscape and Its Geospatial Factors Behind

Soundscape is the production of sounds and the acoustic environment, and it emphasizes peoples' perceiving and experiencing process in the context. To this end, this paper focuses on the Pearl River Delta in China, and implements an empirical study based on the soundscape evaluation data from the Participatory Soundscape Sensing (PSS) system, and the geospatial data from multiple sources. The optimal variable set with 24 features are successfully used to establish a random forest model to predict the soundscape comfort of a new site (F1 = 0.61). Results show that the acoustic factors are most important to successfully classify soundscape comfort (averaged relative importance of 17.45), subsequently ranking by built environment elements (11.28), temporal factors (9.59), and demographic factors (9.14), while landscape index (8.60) and land cover type (7.71) seem to have unclear importance. Furthermore, the partial dependence analysis provides the answers about the appropriate threshold or category of various variables to quantitatively or qualitatively specify the necessary management and control metrics for maintaining soundscape quality. These findings suggest that mainstreaming the soundscape in the coupled natural-human systems and clarifying the mechanisms between soundscape perception and geospatial factors can be beneficial to create a high-quality soundscape in human habitats.

The Sound of a Circular City: Towards a Circularity-Driven Quietness

The circular economy paradigm can be beneficial for urban sustainability by eliminating waste and pollution, by circulating products and materials and by regenerating nature. Furthermore, under an urban circular development scheme, environmental noise can be designed out. The current noise control policies and actions, undertaken at a source-medium-receiver level, present a linearity with minimum sustainability co-benefits. A circular approach in noise control strategies and in soundscape design could offer numerous ecologically related co-benefits. The global literature documenting the advantages of the implementation of circular economy in cities has highlighted noise mitigation as a given benefit. Research involving circular economy actions such as urban green infrastructure, green walls, sustainable mobility systems and electro-mobility has acknowledged reduced noise levels as a major circularity outcome. In this research paper, we highlight the necessity of a circularity and bioeconomy approach in noise control. To this end, a preliminary experimental noise modeling study was conducted to showcase the acoustic benefits of green walls and electric vehicles in a medium-sized urban area of a Mediterranean island. The results indicate a noise level reduction at 4 dB(A) when simulating the introduction of urban circular development actions.

Tranquillity in Urban Classical Chinese Gardens and Modern Parks: The Effect of Natural and Contextual Features

Parks and green spaces are an integral part of many urban areas. Such spaces offer a variety of psychological, physical and social benefits promoting a stronger sense of community and allowing people to cope better with everyday stress. These parks are often designed to provide tranquillity for people, and it is now an emerging area of policy in the promotion of quality of life. Tranquillity is considered a natural asset. Although they are vital, tranquil spaces are under threat, and it is, therefore, important to identify and understand such places so that they can be further planned and managed for the benefits that they provide. This study conceptualises the understanding of tranquillity and determines the extent to which a tranquil environment can be achieved. The study identified six parks referred to as “modern parks (MPs)” and “classical Chinese gardens (CCGs)”. Three parks each are located in Hong Kong and Guangzhou. Questionnaires were used to ascertain the importance of tranquil areas and the contribution of park components towards tranquillity. This study investigates the contribution of park elements that include both natural and contextual features. Furthermore, park characteristics and park elements were similarly identified. There were clear differences between natural and contextual features in terms of their potential contribution towards park users’ perceived tranquillity. There is also a striking importance and potential contribution of contextual features within classical Chinese gardens in relation to perceived tranquillity. This study concludes that there is the need to continue to enhance the quality of park spaces with regard to fostering tranquillity in urban areas.

Singapore Soundscape Site Selection Survey (S5): Identification of Characteristic Soundscapes of Singapore via Weighted k-Means Clustering

The ecological validity of soundscape studies usually rests on the choice of soundscapes that are representative of the perceptual space under investigation. For example, a soundscape pleasantness study might investigate locations with soundscapes ranging from “pleasant” to “annoying”. The choice of soundscapes is typically researcher led, but a participant-led process can reduce selection bias and improve result reliability. Hence, we propose a robust participant-led method to pinpoint characteristic soundscapes possessing arbitrary perceptual attributes. We validate our method by identifying Singaporean soundscapes spanning the perceptual quadrants generated from the “Pleasantness” and “Eventfulness” axes of the ISO 12913-2 circumplex model of soundscape perception, as perceived by local experts. From memory and experience, 67 participants first selected locations corresponding to each perceptual quadrant in each major planning region of Singapore. We then performed weighted k-means clustering on the selected locations, with weights for each location derived from previous frequencies and durations spent in each location by each participant. Weights hence acted as proxies for participant confidence. In total, 62 locations were thereby identified as suitable locations with characteristic soundscapes for further research utilizing the ISO 12913-2 perceptual quadrants. Audio–visual recordings and acoustic characterization of the soundscapes will be made in a future study.

Exploring the Multisensory Interaction between Luminous, Thermal and Auditory Environments through the Spatial Promenade Experience: A Case Study of a University Campus in an Oasis Settlement

This paper aimed to develop a multisensory approach in a university campus, based on quantitative and qualitative approaches, investigating sense walk experiences (thermo-visual sound walk) under interactions of luminous, thermal, and auditory environments. The study was conducted in October 2021, in Chetma university campus in Biskra city, southern Algeria, which remains a famous oasis settlement of arid regions over the country. A comparative and correlation analysis was performed between the physical dimensions collected through a walking experience in three campus routes (outdoor, semi-outdoor and indoor). In addition, a multisensory survey of the walking experience on perceptual dimensions was evaluated in parallel to the empirical contribution. The paper shows that walkers’ thermal levels were balanced between neural and slightly hot in different spatial aspects. The glare was almost unperceived regarding the luminous conditions in the study site. The auditory experience reveals that the conducted points were generally quiet and well placed for educational requirements. Findings also show a strong relationship between the physical dimensions of the luminous and auditory environment. Furthermore, the findings suggest that the thermal and luminous environments are more perceptible than the auditory environment for the walkers of the outdoor and indoor routes. In contrast, the semi-outdoor route is often perceptible by the perceptual dimensions of the luminous and auditory environments. The findings on sensorial thresholds and spatial adaption are essential for the educational practices’ architectural and urban strategies for the Saharan cities and oasis settlements.

Relationship between Subjective and Biological Responses to Comfortable and Uncomfortable Sounds

Various kinds of biological sensors are now embedded in wearable devices and data on human biological information have recently become more widespread. Among various environmental stressors, sound has emotional and biological impacts on humans, and it is worthwhile to investigate the relationship between the subjective impressions of and biological responses to such sounds. In this study, the relationship between subjective and biological responses to acoustic stimuli with two contrasting kinds of sounds, a murmuring river sound and white noise, was investigated. The subjective and biological responses were measured during the presentation of the sounds. Compared with the murmuring river sound, the white noise had a significantly decreased EEG-related index of α-EEG and HRV-related index of SD2/SD1. The correlation between each index of subjective and biological responses indicated that α-EEG was highly correlated with the results of subjective evaluation. However, based on a more detailed analysis with clustering, some subjects showed different biological responses in each trial since they felt the sound was powerful when listening to the murmuring river sound, as well as feeling that it was beautiful. It was suggested that biological responses to sound exposure may be affected by the impression of the sound, which varies by individual.

Evaluation of Acoustic Noise Level and Impulsiveness Inside Vehicles in Different Traffic Conditions

Recently, the issue of sound quality inside vehicles has attracted interest from both researchers and industry alike due to health concerns and also to increase the appeal of vehicles to consumers. This work extends the analysis of interior acoustic noise inside a vehicle under several conditions by comparing measured power levels and two different models for acoustic noise, namely the Gaussian and the alpha-stable distributions. Noise samples were collected in a scenario with real traffic patterns using a measurement setup composed of a Raspberry Pi Board and a microphone strategically positioned. The analysis of the acquired data shows that the observed noise levels are higher when traffic conditions are good. Additionally, the interior noise presented considerable impulsiveness, which tends to be more severe when traffic is slower. Finally, our results suggest that noise sources related to the vehicle itself and its movement are the most relevant ones in the composition of the interior acoustic noise.

Effect of Road and Railway Sound on Psychological and Physiological Responses in an Office Environment

The present study aims to explore the psychophysiological impact of different traffic sounds in office spaces. In this experiment, 30 subjects were recruited and exposed to different traffic sounds in a virtual reality (VR) office scene. The road traffic sound and three railway sounds (conventional train, high-speed train, and tram) with three sound levels (45, 55, and 65 dB) were used as the acoustic stimuli. Physiological responses, electrodermal activity (EDA) and heart rate (HR) were monitored throughout the experiment. Psychological evaluations under each acoustic stimulus were also measured using scales within the VR system. The results showed that both the psychological and the physiological responses were significantly affected by the traffic sounds. As for psychological responses, considerable adverse effects of traffic sounds were observed, which constantly increased with the increase in the sound level. The peak sound level was found to have a better performance than the equivalent sound level in the assessment of the psychological impact of traffic sounds. As for the physiological responses, significant effects of both the acoustic factors (sound type and sound level) and the non-acoustic factors (gender and exposure time) were observed. The relationship between sound level and physiological parameters varied among different sound groups. The variation in sound level hardly affected the participants’ HR and EDA when exposed to the conventional train and tram sounds. In contrast, HR and EDA were significantly affected by the levels of road traffic sound and high-speed train sound. Through a correlation analysis, a relatively weak correlation between the psychological evaluations and HR was found.

Effects of Evocative Audio-Visual Installations on the Restorativeness in Urban Parks

Road traffic noise is responsible for several negative health effects for citizens in modern cities. Inside urban parks, which citizens use for social inclusion and cohesion, psychological and physical restoration, and physical activities, road traffic noise may significantly reduce the potential of these places to induce or enhance well-being. Although access restriction schemes and screens could be effective solutions to limit noise inside urban park areas, preserving their potential regenerative role may engender mobility, social, aesthetic, and architectural issues. Due to the positive effects that natural elements and water sounds can have on human perception, and based on the previous findings of the beneficial effects of audio-visual installations, this paper investigates the possibility of using audio-visual installations that simply evoke some natural features to improve the restoration of individuals inside urban parks. The study has been carried out using immersive virtual environments in two different experimental laboratory sessions in Hong Kong (China) and Aversa (Italy). The results showed that the positive effects provided by evocative installations were similar to those provided by traditional installations. Furthermore, the effects on the restoration increased as the installations became larger and included enveloping shapes. Furthermore, we found that the amount of evocative water installations’ material was responsible for changes in restoration. In contrast, the Chinese groups were less influenced by these installations.

Sound Water Masking to Match a Waterfront Soundscape with the Users’ Expectations: The Case Study of the Seafront in Naples, Italy

In the last decades, the soundscape approach has attracted the attention of architects and urban planners, leading them to incorporate the acoustic features into the enjoyment of their creations. One of the key aspects for an appreciated urban environment is to match the expectations of the users. In this study, the matching of the waterfront soundscape with the users’ expectations is evaluated by laboratory tests using semantic differential scales applied to reproduced virtual scenarios obtained adding different water sound pressure levels (SPLs) to the original in-situ setting. The tests were carried out by an immersive virtual reality (IVR) device, using 360° videos and spatial audio recorded in two sites of the waterfront in Naples, Italy. The scenarios were presented to the participants according to three experimental protocols, namely audio-only (A), video-only (V), and simultaneous audio-video (AV) reproduction. The examined different acoustic scenarios were the original one recorded in situ and others obtained adding seawater sounds at SPL increments of 5 dB. The results show that all the scenarios with water sounds added are rated more pleasant than the original one for the audio-only scenario. When video and audio are displayed simultaneously, two scenarios are more pleasant than the original one, likely because there is a need for coherence between the water sound SPL heard and the visible noise sources. Sounds coherent with the type of shore show a higher matching with expectations and pleasantness appraisals, rather than those that are uncoherent with the layout scenario.

A Comparison between Numerical Simulation Models for the Prediction of Acoustic Behavior of Giant Reeds Shredded

Giant reeds represent a natural fiber widely available in some areas of the world. Its use can be particularly useful as the uncontrolled growth of giant reeds can be a problem because large areas are invaded by them and the crops are damaged. In this study, two models of numerical simulation of the acoustic behavior of giant reeds were put in comparison: the Hamet model and a model based on artificial neural networks. First, the characteristics of the reeds were examined and the procedures for the preparation of the samples to be analyzed were described. Then air flow resistance, porosity and sound absorption coefficient were measured and analyzed in detail. Finally, the results of the numerical modeling of the acoustic coefficient were compared. The neural network-based model showed high Pearson correlation coefficient value, indicating a large number of correct predictions.

The Influence of Audio-Visual Interactions on Psychological Responses of Young People in Urban Green Areas: A Case Study in Two Parks in China

Audio-visual interactions in green spaces are important for mental health and wellbeing. However, the influence of audio-visual interactions on psychological responses is still less clear. This study introduced a new method, namely the audio-visual walk (AV-walk), to obtain data on the audio-visual context, audio-visual experiences, and psychological responses in two typical parks, namely Cloves Park and Music Park in Harbin, China. Some interesting results are as follows: First, based on Pearson’s correlation analysis, sound pressure level and roughness were significantly correlated with psychological responses in Cloves Park (p < 0.05). Second, the results of stepwise regression models showed the impact intensity of acoustic comfort was 1.64–1.68 times higher than that of visual comfort on psychological responses of emotion dimension, while visual comfort was 1.35–1.37 times higher than acoustic comfort on psychological responses of cognition dimension in Music Park. In addition, an orthogonal analysis diagram explained the influence of audio-visual interactions on psychological responses of young people. The audio-visual context located beside the waterscape with a relatively higher level of acoustic and visual comfort was the most cheerful (2.60), relaxed (2.45), and energetic (2.05), while the audio-visual context close to an urban built environment tended to be both acoustically and visually uncomfortable, and the psychological state was decreased to the most depressed (−0.25), anxious (−0.75), fatigued (−1.13) and distracted (−1.13).