The validation of acoustic environment simulator to determine the relationship between sound objects and soundscape

An acoustic environment simulator is a system that facilitates acoustic environment composition by controlling the parameters of sound objects (both background and sound events), allowing the user to compose and compare soundscapes against their expectations. By using the acoustic environment simulator, data regarding parameters of sound objects, such as their sound level and selection, can be obtained. Furthermore, these data can be used to understand the relationship between the sound objects and the soundscapes. This paper describes the development and validation of an acoustic environment simulator, which can be used to design a complex acoustic environment in the laboratory according to the expectations of the user. Validation of the simulated soundscape, whether the composed acoustic environment has the same soundscape dimension characteristics as previous in-situ and other laboratory experiments, was conducted by reproducing acoustic environment compositions using a two-dimensional ambisonic system in the laboratory. Listener responses on semantic differential scales were reduced to three reliable soundscape dimensions by principal component analysis: Calmness/Relaxation (40%), Dynamics/Vibrancy (12%), and Communication (11%). These three soundscape dimensions are consistent with a previous study conducted in situ. The results reported here indicate that acoustic environment composition can successfully imitate the soundscape dimensions of an actual acoustic environment

Comparison of noise indicators in an urban context

Inter-Noise 2016, 45th International Congress and Exposition of Noise Control Engineering, HAMBOURG, ALLEMAGNE, 21-/08/2016 - 24/08/2016Noise is a major environmental issue, which gave birth in the last decades to the development of many engineering methods dedicated to both its estimation and mitigation. The specificity of the noise pollution problem lies in the complexity of human hearing and subjective assessment, and in the high spatiotemporal variation and rich spectral content of the noise generated by a wide variety of sources in urban context. Indicators that encompass all these dimensions are required for the description of sound environments and for the evaluation of noise mitigation strategies. This paper compares usual and more specific indicators, dedicated to environmental noise analyses, by means of a literature review. The comparison is based on the three following criteria: i) the ability of indicators to describe and physically categorize the urban sound environments, ii) the relevance of indicators for describing the perceptive appreciations of urban sound environments, iii) the ability of indicators to be estimated through classical or more advanced traffic noise estimation models. A discussion compares the pro and cons of the selected indicators in an operational scop

Noise and Vibration Control in the Built Environment

With global urbanization rapidly rising and the increasing need of high-quality built environments, the requirement of achieving improved sound quality, both for outdoor and indoor environments, has received a lot of attention. This Special Issue collection reflects the current state of the art, with 12 papers covering environmental acoustics; the influence of soundscapes on people’s behavior; soundscape pleasantness estimation; tranquility; perceived quality of sonic environments; sound and vibration-related health complaints concerning tramways; and the disturbance of construction machines; as well as in building and room acoustics, including natural ventilation-enabling façade noise control devices; the effect of external shading devices; rating method of airborne sound insulation; water supply and drainage noise, and the effect of diffusive surfaces in auditoria. Some papers cover research on the engineering aspects of sound and vibration, such as sound propagation and noise control techniques, as well as perception aspects of sound, such as indoor acoustic comfort and environmental soundscapes. The book is prefaced by Prof. S Wu, entitled ‘Sustainable Urban Sound Environment’

A new methodology for modelling urban soundscapes: a psychometric revisitation of the current standard and a Bayesian approach for individual response prediction

Measuring how the urban sound environment is perceived by public space users, which is usually referred as urban soundscape, is a research field of particular in terest for a broad and multidisciplinary scientific community besides private and public agencies. The need for a tool to quantify soundscapes would provide much support to urban planning and design, so to public healthcare. Soundscape liter ature still does not show a unique strategy for addressing this topic. Soundscape definition, data collection, and analysis tools have been recently standardised and published in three respective ISO (International Organisation for Standardization) items. In particular, the third item of the ISO series defines the calculation of the soundscape experience of public space users by means of multiple Likert scales. In this thesis, with regards to the third item of the soundscape ISO series, the soundscape data analysis standard method is questioned and a correction paradigm is proposed. This thesis questiones the assumption of a point-wise superimposition match across the Likert scales used during the soundscape assessment task. In order to do that, the thesis presents a new method which introduces correction values, or metric, for adjusting the scales in accordance to the results of common scaling behaviours found across the investigated locations. In order to validate the results, the outcome of the new metric is used as tar get to predict the individual experience of soundscapes from the participants. In comparison to the current ISO output, the new correction values reveal to achievea better predictability in both linear and non-linear modelling by increasing the ac-curacy of prediction of individual responses up to 52.6% (8.3% higher than theaccuracy obtained with the standard method).Finally, the new metric is used to validate the collection of data samples acrossseveral locations on individual questionnaires responses. Models are trained, in aiterative way, on all the locations except the one used during the validation. Thisprocedure provides a strong validating framework for predicting individual subjectassessments belonging to locations totally unseen during the model training. The results show that the combination of the new metrics with the proposed modelling structure achieves good performance on individual responses across the dataset withan average accuracy above 54%. A new index for measuring the soundscape is fi-nally introduced based on the percentage of people agreeing on soundscape pleas-antness calculated from the new proposed metric and performing a r-squared valueequals to 0.87.The framework introduced is limited by cultural and linguistic factors. Indeed,different corrected metric space are expected to be found when data is collected from different countries or urban context. The current values found in this thesis areso expected to be valid in large British cities and eventually in international hub andcapital cities. In these scenarios the corrected metric would provide a more realisticand direction-invariant representation of how the urban soundscape is perceived compared to the current ISO tool, showing that some components in the circumplex model are perceived softer or stronger according to the dimension. Future research will need to understand better the limitations of this new ramework and to extendand compare it towards different urban, cultural, and linguistic contexts

Visualisation and auralisation for perception-driven decision supports in planning: A comparative review

Visualisation and auralisation are among the essential technologies for perception-driven decision support in landscape planning and soundscape planning, respectively. By making proposed developments and environmental changes visible and audible, they allow decision-makings based on perceptual experience, providing a “common language” that all the stakeholders are capable of using to communicate and to exchange ideas. While they share common function and criteria when used for decision support in planning, they are not in parallel developments and have been approached differently regarding their applications. This chapter comparatively reviews the developments and applications of visualisation and auralisation for perception-driven decision support in planning, aiming to provide technological and methodological insights into the two interconnected yet somewhat independent subjects. This led to indications for new developments and optimized applications in the near future. The chapter addresses three issues: validity, contents to present, and ways to present

Research into the practical and policy applications of soundscape concepts and techniques in urban areas

Executive Summary 1 The aim of this review was to investigate existing research into soundscape concepts and to produce recommendations for future research into the practical identification, management and enhancement of soundscapes in urban areas. 2 Existing research on soundscapes was investigated using four methods: i. a survey of more than 500 papers in the academic literature, ii. an analysis of 27 case studies of soundscape assessment, iii. an analysis of 15 case studies of soundscape design, and iv. interviews with five key soundscape experts. Analysis of this data was conducted to identify significant gaps in the knowledge base and suggest a way of obtaining a practical soundscape assessment method. 3 Soundscapes were found to be a highly multi-disciplinary topic, with many different ideas, concepts, aims and methods evident in the literature. The definition of the term soundscape is itself not settled; for the purposes of this project, we have defined it as “the totality of all sounds within a location with an emphasis on the relationship between individual’s or society’s perception of, understanding of and interaction with the sonic environment.” 4 This review highlights that a range of methodological approaches have been used to establish classifications and categorisations of sounds and soundscapes. The relationship between different categories of sounds and their interaction needs to be considered to increase the understanding of soundscape assessments and to derive soundscape classifications. 5 The different methods and tools used to assess soundscapes, in a variety of locations, each have advantages and disadvantages; using a number of methods in one case study can help to mitigate against the disadvantages of any one method. The case studies assessed in this report demonstrate the importance of individual and demographic similarities/differences, people’s behaviour, physical aspects of the soundscape, other sensory and environmental elements, and the general location and context, in understanding and assessing soundscapes. 6 Soundscape assessments involving a subjective component have highlighted a number of variables that play a part in the assessment. These include the individual’s knowledge and prior experience of the soundscape, the meaning they derive from it, their attitude towards the sound source, their behaviour, their noise sensitivity, demographic and cultural dimensions, and their sense of control over the noise. 7 Research has shown that sometimes a soundscape is perceived as a collection of the individual sounds of which it is comprised; soundscape assessments are therefore related to the assessment of those sound types. This implies that soundscape assessment relies upon the identification of the sounds, the prominence of the sounds, and potentially the ratio of certain sound types to other sound types within the soundscape. It is also highlighted that, because the soundscape varies over time, note must be taken of the fact that any soundscape assessment relates to a singular moment in time. Furthermore, research has shown that soundscape assessments can be dependent on an individual’s memory (when using subjective assessments methods) and/or the segment of the soundscape that was recorded (when playing back recorded soundscapes in a laboratory situation). 8 Multi-sensory experience is also shown to be highly relevant to soundscape assessment and must therefore be acknowledged as soundscapes are not perceived in sensory isolation; in particular audio-visual interactions have been shown to have an effect on soundscape perception. Many researchers point to the importance of understanding the full environmental and social context for soundscape assessment, the relevance of comparing similar place types, and the effect of moving between one soundscape and another on an assessment. 9 Turning to the subject of soundscape design, it is noted that there is a dearth of case studies involving the modification and design of soundscapes, both in the UK and internationally. The rationale behind many of the case studies’ focus upon or consideration of sound was the improvement of a soundscape that was negatively affected by the sound of traffic. Approaches to soundscape design varied, ranging from the use of noise control elements, such as barriers and absorbers, to the utilisation or exploitation of natural elements that already exist in the location. Some case studies introduced sounds to the soundscape, in particular water sounds, while others incorporated specific sonic art installations to alter the soundscape or detract attention from existing features of the soundscape. A number of case studies used design alterations to improve the soundscape and perception of the soundscape including altering visual aspects of the place, altering the layout of the area, pedestrianisation of the area, and providing entertainment facilities (e.g. cafes). 10 Case studies whereby design modifications or interventions have taken place, have had little or no formal evaluation of their success. The studies that were evaluated used a number of different methods involving both objective and subjective measures and included the experimental comparison of subjective ratings, observations of people’s behaviour, recognition and awards for good designs, and level of complaints about the soundscape. This demonstrates that different evaluation tools may be necessary dependent upon the type of soundscape intervention being evaluated. Additionally, by combining methods to produce an interdisciplinary evaluation, a more accurate understanding of the success of the soundscape design is possible, hence improving future interventions. 11 The relationship between environment and individual is complex, with many factors, some of which cannot currently be quantified. Important factors include: prominent individual sound sources, the interaction of sources, other sensory stimuli and contextual and individual factors such as meaning, and expectation. Some of these factors can be captured by subjective rating scales for high-level concepts like ‘calmness’, ‘vibrancy’ and ‘spaciousness’. Other factors, such as the semantic meaning of a soundscape are best characterised currently by qualitative descriptors. There are good prospects for developing objective acoustic metrics to evaluate some factors but in most cases this work is still at an early stage, and the methods developed so far have only been applied in specific contexts; to provide metrics that are more broadly applicable they would need to be evaluated in a broader range of locations and conditions. The expert interviews and case studies illustrated the diversity of views across different disciplines on the most promising soundscape methods. All the interviewees agreed on the need for an interdisciplinary approach, and on the need to retain some form of subjective rating when assessing soundscapes. 12 Ultimately, six important gaps have been identified in the soundscape knowledge base. These are areas where more research would significantly improve understanding soundscape assessments. These gaps have been identified as: i. a lack of genuinely interdisciplinary projects (characterised by a shared perspective) instead of multidisciplinary projects (where researchers work in parallel within their own disciplines). These are needed to deal with the multidimensional experience of soundscape perception. ii. a lack of basic knowledge on many aspects of soundscape cognition, perception and classification. iii.a need for large-scale robust field trials of soundscape assessment methods instead of the more common experiment of a new method in a single location. iv. a need to develop more soundscape-specific indicators and tools that could eventually be used for soundscape design. v. a need to rigorously assess deliberate soundscape interventions to understand which design aspects work and which do not. vi. a lack of a close connection between soundscape research, design and planning practice. 13 Finally, a new research project is proposed to develop a robust field assessment method. The aim of this project is to develop a method based on existing research methods but introducing greater confidence by trialling the method across many real urban soundscapes. Options are presented for developing a purely qualitative assessment tool or one that incorporates and integrates both qualitative and quantitative ratings. 14 We recommend that a first step for an assessment method, which could realistically be developed in the near future, should be based on qualitative methods. A second iteration of this soundscape assessment tool could supplement the qualitative techniques with quantitative methods, first based on subjective rating scales and eventually on objective metrics which predict the subjective ratings

Soundscape composition and relationship between sound objects and soundscape dimensions of an urban area

Previous studies of soundscape have tried to understand the relationship between sound objects and soundscape rating, resulting in the categorisation of general sound objects according to positive or negative perceptions. This study tries to determine the relationship and interaction between specific sound objects in a soundscape and the soundscape dimensions. This study is divided into four steps: testing the validity of soundscape study in the laboratory, the application of soundscape recording, the development of a soundscape environment simulator, and the determination of the relationship between specific sound objects and soundscape dimensions according to expectations and preferences regarding sound objects. The first step confirms three reliable soundscape dimensions from in situ and laboratory experiments (measured using the same semantic scales for both): Relaxation, Dynamics and Communication. It also confirms the validity of laboratory experiments compared with in situ ones. Furthermore, the effect of sound level adjustment on soundscape reproduction in the laboratory is investigated.The second step, using soundscape recording, confirms that the common method of analysing the relationship between sound objects and soundscape rating (in situ experiment and soundscape reproduction) is not adequate due to limitations in the selection of sound objects and control over their parameters. A different method is proposed to deal with these limitations: using a soundscape environment simulator. A soundscape environment simulator is therefore developed to understand the relationship and interaction between sound objects in a soundscape and the perception of the soundscape. The soundscape environment simulator can be used to compose complex soundscapes. Furthermore, semantic differential analysis confirms that soundscape composition can represent an actual soundscape. Finally, two experiments are conducted using the soundscape environment simulator to study expectations and preferences of sound objects in a soundscape. The study succeeds in explaining the relationship and interaction between specific sound objects and the rating of soundscape. Furthermore, a perception model regarding the preference of sound objects used in the soundscape environment simulator and the soundscape dimensions is developed and implemented in the soundscape environment simulator. This implementation allows the simulator to predict perceptions of the soundscapes composed by the simulator

The effects of expectation on the perception of soundscapes

This thesis discusses how expectation is a contributory factor in the perception ofsoundscapes. "Soundscape" is a term attributed to R.Murray Schafer to define the acousticenvironment, a recent ISO workgroup has proposed a formal definition as the "perception andunderstanding of an acoustic environment, in context, by the individual, or by a society" Assuch there is a move away from traditional acoustic methods of understanding environmentalsound towards a more holistic, and interdisciplinary, approach to the sound environment.Previous soundscape research has identified the importance of semantic meaning attributed tosoundscapes focusing on investigating linguistic and textual approaches of how peopledescribe the soundscape. This thesis aims to extend the concept of meaning to give an insightinto what particular soundscapes mean to people, and if this related to a predefinedexpectation based on context. This work expands Truax's notion of soundscape competence,and investigates how people perceive the soundscape. In particular how expectation of aparticular space impacts on the perception of that space. This in turn addresses the issue ofdefining a context for a space and understanding how the soundscape is of importance toperception of spaces.The research which forms this work uses a number of interdisciplinary methods, from thefields of acoustics, social science and psychology, with the aim of developing a newqualitative and quantitative methodology for soundscape research. The work consists ofqualitative fieldwork, and the development of a soundscape simulator in the laboratory.Through the use of an enhanced version of soundwalking, participants were asked questionsaimed to analyse their pre-determined environmental expectation and their actual experienceof a number of different spaces, and how this impacts on their perception and evaluation ofthe soundscape. The soundscape simulator was a tool by which participants could control anddesign their own soundscapes, whilst providing useful quantitative and qualitative data aboutchoices made in the design process. Soundscape expectation is shown to relate not only tocompetence in perceiving the components of the soundscape but also to attitudes towardssafety, social norms, accepted behaviour, visual aesthetics and control attributed to the space.Expectation based on competence forms the basis of place expectation or context, and relatesto the overall perception of the soundscape for each space. When one or more of these factorsconflict with a perceived place expectation, then perception of the soundscape becomes moreimportant and impacts on the perception of the space. This work concludes that the meaningof a soundscape and its perception is related to an individual's expectation of the context of aspace

Development of a window system with optimised ventilation and noise-reduction performance: an approach using metamaterials.

Noise transmission is a key factor regarding indoor comfort and energy-smart Architecture and Engineering. In most cases, occupants of the building must choose between a naturally ventilated indoor environment or a quiet one. On the other hand, the acoustic metamaterials (AMMs) allow more customisable physical properties according to their spatial configurations, proving significant merits over traditional architecture and engineering materials. This PhD study will investigate AMMs techniques to develop a window system that can control the incoming noise while allowing natural ventilation. This is a crucial point for AMMs research. So far, even if many solutions have been developed to pursue this objective, they still lack ergonomics and human perception analysis. Through a multi-disciplinary methodology, the author first a) highlighted which are the ergonomic principles that add value to the window system from the users perspective, then b) investigated a series of suitable AMMs techniques to be applied for noise reduction and natural ventilation, c) developed a specific AMM design suitable to follow those ergonomic principles previously highlighted and assessed it through human perception, and finally d) optimised a full-scale prototype for a broad acoustic range and customisable ergonomic application. Social science, ergonomic, numerical, analytical and experimental studies were used throughout the PhD project to draw a full-scale window prototype using AMMs to allow natural ventilation independently from the outdoor noise situation. The so-called acoustic metawindow (AMW) allows Transmission Loss (TL) of 10-80dB on a significant frequency range for human hearing (50-5000Hz) in an open configuration while allowing sufficient natural ventilation. In addition, the AMW is proved to positively impact the indoor environment from both physical and human perception points of view thanks to its ergonomic nature. This project will open a new AMMs field of investigation that is not limited to noise reduction but also includes outdoor stimuli optimisation towards a more comprehensive indoor comfort