The acoustic designer: Joining soundscape and architectural acoustics in architectural design education

Origins of acoustic design theory

It is widely acknowledged that the first person writing about Architectural Acoustics was the architect-engineer Marcus Vitruvius Pollio.^7–9 Vitruvius wrote the acclaimed 10 books on architecture, called ‘De Architectura’, between 40 and 20 bc. ¹⁰ This publication has been for many centuries the first and only handbook on architecture and architectural acoustics, fostering interest in the discipline. According to Walden, ¹¹ Vitruvius was aware of the teachings of the father of medicine, Ippocrate. When planning new buildings and in the specific theatres, he advises that ‘a site as healthy as possible’ (p. 137) be selected. ¹² Vitruvius also acknowledges the expertise of the Greek architects in designing open-air theatres.

Hence, the ancient architects, following the footsteps of nature, perfected the ascending rows of seats in theatres from their investigations of the ascending voice, and, by means of the canonical theory of the mathematicians and that of the musicians, endeavoured to make every voice uttered on stage come with greater clearness and sweetness to the ears of the audience. For just as musical instruments are brought to perfection of clearness in the sound of their strings by means of bronze plates or horn echeia, so the ancients devised methods of increasing the power of the voice in theatre through the application of harmonics. ¹²

Vitruvius introduced his famous theory on dis-sonnantes, con-sonnantes, circum-sonnantes and re-sonnantes design solutions, as reminded by Postma et al. ⁸ and D’Orazio and Nannini. ¹³ Thanks to his contribution, acoustic design through centuries largely focused on the control of the building shape and the application of the resonant tuning devices called echeia. ¹⁴

Acoustic design and medieval tradition

During the Middle Ages, we have no trace of important acoustic developments, although the echeia were found in various medieval churches, inserted into the walls, with the belief that they could improve the acoustics of the interior space and the intelligibility of the spoken word. ¹⁵ These devices were for example found in Serbian churches spanning from medieval times to the 17th century. ¹⁶ However, the measurement of these resonators showed that they would not have any effect on typical choral and preaching production which would take place in these churches, leaving space to the hypothesis that they were installed primarily for oral tradition or as a construction material. These devices were found to achieve diffusion in Swiss churches by Desarnaulds. ¹⁷

Baumann and Haggh ¹⁵ demonstrated through the geometrical analysis of reflection paths how in the 15th century the positioning of the organ in Santa Maria del Fiore in Florence might have followed specific acoustic design principles. In the 1500s and the 1600s, architectural acoustics saw a renovated interest, guided by the need to design new playhouses, such as the Elizabethan theatres in London and Opera theatres in Italy. ¹³ It is nowadays possible to explore this evolution through online resources, such as the website theatre-architecture (https://www.theatre-architecture.eu).

Acoustic design and modern science

Shortly after Giuseppe Biancani and Marin Mersenne laid the foundation of the modern science of acoustics, in 1650 the Jesuit scholar Athanasius Kircher published in Rome the Musurgia Universalis, followed by the similar Phonurgia Nova in 1673.^8,18,19 Kircher charmingly named acoustics as the ‘magic art’ of the bent sound – Magia Phonocamptica – and drafted inventions to amplify sound through pipes in buildings (Figure 1), hydraulic organs, and theories based on geometrical projections and listening experiments with choirs, which he called Musica per Echo. (p.50) ²⁰ In these books, he used the word Architectura Echonica to describe the study and the controlled design of architectural interactions with sounds. Further insights on the development of the science of Acoustics from its origins can be found in Hunt, ¹⁸ who remarked the importance of observation and experiments in such evolution.

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Figure 1.

Acoustic Designs by Athanasius Kircher, 1673.

Predicting echoes and reverberation times

Architectural acoustics developed as a fundamental part of the design of performance spaces, pushing the limits of innovation.^14,21,22 Recently, Postma et al., ⁸ D’Orazio and Nannini ¹³ and Postma ²³ provided an examination of the main design strategies adopted before the discovery of the Reverberation Time (RT60) formula by Sabine, which took place around 1898.^23,24 Pre-Sabinian strategies to solve acoustic design problems involved several methods. Postma et al. ⁸ differentiated in design approaches, such as copying or upscaling acoustically satisfying buildings and rooms, and physics-based design approaches, which can be divided into undulatory and geometrical acoustics. The undulatory approaches were based on the concept of circulation and obstruction of sound, which can be traced back to Vitruvius’ suggestions. ⁸ Vovolis ²⁵ suggested that geometrical methods were already used in Greek open-air theatres to avoid centralised focusing effects.

According to Postma, ²³ at the end of the 18th century, an alternative acoustic design guideline emerged, named echo theory, based on the ‘quantification of the perception threshold between direct and reflected sounds’. ⁸ Postma et al. ⁸ have also identified an additional acoustic guideline, based on the undulatory ‘circulation of sound’ and ‘unobstructed propagation’ approaches, which employed ‘a speaking person and human observer judging audibility/intelligibility as a function of distance and direction’, ultimately leading to limiting the size of audience areas.

Designing architectural acoustics

With the formulation of the RT60 by Sabine,^26,27 explaining the influence of volume and absorbent surfaces on the time needed for sound to decay until being inaudible, a rediscovered interest in acoustics spread to the design of everyday spaces. Acoustic consultants, already operating at the time of Sabine,^24,28 could test in real architectural settings their hypotheses aimed at controlling the reverberation phenomenon. In this context, the experimental application of innovative materials, also driving the manufacturing and design industry, made a large number of spaces more absorbent. ²⁴

Over the course of time, opera houses, theatres, and concert halls had been the primary playground to compare design solutions and test innovations, leading to the standardisation of room acoustics measurement procedures, at the beginning focused mainly on performance spaces. In order to help enable research reproducibility in the field, the standard ISO 3382 was released in 1975 to uniform the measurement of reverberation time, later updated in ISO 3382:1997 to include other acoustic parameters.^29,30 In the recent years, the Building Acoustics Technical Committee (ISO/TC 43/SC 2) has extended the focus of the ISO 3382 from performance spaces ³¹ to ordinary rooms ³² and open plan offices. ³³

Simulation and auralisation

To be able to demonstrate the reliability of design solutions, practitioners were (and still are) supported by calculation strategies which need to be solid in mathematical and physical theory and guarantee the proposed design outcomes. Theatre acoustic design experimentation developed also through the analysis of sound propagation in scale models, progressively assisted by digital simulation tools, allowing to quickly compare results and organise them in tables and graphs. ³⁴ The combination of computational improvements in both audio signal processing and computer graphics progressively led to the possibility to display information related to acoustic parameters next to the geometrical representation of the digital model. In the last few decades, practitioners have been able to visually inspect critical areas of the design by looking at heat-maps superimposed on the two- (2D) or three-dimensional (3D) views of model, as well as to study reflection paths and their spatial distribution in time.

Auralisation, ‘the creation of audible acoustic sceneries from computer-generated data’, ³⁵ has helped in the recent years to listen to acoustic design solutions for architectural spaces and evaluate perceptually their acoustic signature, represented by a room impulse response (RIR). An RIR corresponds to the response of the room to the excitation of a given signal, emitted by a source with a given set of coordinates, as recorded by a receiver placed in a different position. Since 1980, and developing in sophistication in the 1990s, a series of innovative auralisation tools were developed in the audio engineering context.^36–41 Adding another sensory dimension to the potential of computer-aided design (CAD), acoustic simulation software has largely helped through years calculating and hearing – with some limitations – how spaces might sound like, according to their volume, geometry and materials. ⁴²

Thery et al. ⁴³ recently studied the adoption of auralisation in consulting practices, highlighting how their adoption depends on the size of the practice. While smaller practices seem unable to afford the use of these techniques for a lack of resources which include time, money, and skills, higher budget companies adopted this technology often in combination with immersive visualisations, reporting improvements in the collaboration and communication with other stakeholders participating in the construction process. Most of these tools can be considered too expensive also for the pockets of a student, making the simulation of acoustics design choices a technique viable only in large and established professional contexts, or academic departments engaged in acoustic design research.

To meet the demand for more accessible tools which could foster education and creative experimentation in acoustic design, recent developments saw the emergence of real-time auralisation tools such as the SketchUp plug-in RAVEN,^44–46 the open-source EVERTims based on Blender and Juce, ⁴⁷ and the recent Project Acoustics by Microsoft.^48,49 In Milo and Reiss, ⁴² the main technical features of these platforms were reviewed providing some details about their software architecture. Drawing from the results of a survey with 15 architects, their technical potential in educational and architectural practices was also discussed.

We should acknowledge that the more widely adopted simulation platforms, such as Odeon and CATT, have supported the study of valuable heritage buildings,^50–52 as well as public squares. ⁵³ On this hybrid terrain where architectural acoustics and public space design intersect, computer-based simulations ⁵⁴ and scale-model methods ⁵⁵ are often employed to research case-specific problems while testing the interplay between acoustic theory and simulation constraints.

Modelling acoustic designs

In the last decade, the construction industry has made large use of parametric design techniques to achieve digital form-finding or optimise design solutions. ⁵⁶ Non-uniform rational B-spline (NURBS)-based software platform like Rhinoceros offer with the Grasshopper plug-in the possibility to construct design algorithms which create bespoke functions. Pachyderm ⁵⁷ is a plug-in developed within the Foster + Partners practice to verify acoustic design solution. This tool has been employed for the design of acoustically optimised meeting rooms, as shown by Peters, based at the Architecture faculty in Toronto.^58,59 Another example is Aeolus, a computational design tool used to support the acoustic design of a classical music stage shell (ReS), built every year during an architecture and music workshop. ⁶⁰ This practice-based experience aims at engaging student architects in the realisation of a functional acoustic design, while teaching them the rationale behind design choices (Villa Pennisi in Musica).

Critical summary

From the review presented, we notice how the evolution of the architectural acoustics discipline was driven by the desire to design architectural spaces with adequate acoustic performance. Thanks to those spaces primarily dedicated to social listening the historical development of investigation and prediction techniques ultimately created the scientific basis of contemporary acoustic design practices. I suggest that in such cases, two main factors were jointly involved: first, the excitement for higher aesthetic scopes in the acoustic design discipline, helping the delivery of performing arts content through the design of the architectural space also by means of its significance as a sonic experience; second, the will to fulfil the expectations of the clients, together with some apprehension for the future audience judgements.

Architectural acoustic design is today as once still relying on drawing methods, although these can now be managed by a computer. Predictive tools helping solve the complexity in sound wave propagation will increasingly aid designers in imagining new spatialities and study their acoustic effects, with utilitarian as well as aesthetic purposes. Subjective evaluations are still based on listening, although we can now simulate a trial-and-error process in a virtual environment, taking into account the physical laws which were discovered while founding the science of acoustics. A plethora of new inventions in the realm of audio processing and technical design have accompanied this progress. In the next section, I will present the development of the discipline called soundscape, highlighting those cultural aspects of acoustic design which the technical nature of the architectural acoustics discipline might have neglected.

Two perspectives on Acoustic Design

In the Soundscape, Schafer argues that the Bauhaus invented the field of industrial design bringing together the fine arts and industrial craft. ⁶³ Similarly, the interdisciplines acoustic ecology and acoustic design can be further developed in a unified framework covering the science and art of sound. As illustrated in Figure 2, acoustic ecology studies sounds ‘in relationship of life and society’ and thus needs to consider sounds in their original place and study ‘the effects of the acoustic environment on the creatures living in it’. The study of this discipline is preliminary to acoustic design practice. For Schafer, ‘Acoustic design does not, therefore, consist of a set of paradigms or formulae to be imposed on lawless or recalcitrant soundscapes, but is rather a set of principles to be employed in adjudicating and improving them’ (p. 238). These principles, also shown in Figure 2, are listed as follows: ⁶⁷

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Figure 2.

Acoustic ecology and acoustic design principles. ⁶⁷

Schafer goes on to explain that the soundscape of the world unfolds around us as a huge musical composition of which we are audience, performers and composers. He advocates for Acoustic Design not to be controlled from above but to work towards the retrieval of a significant aural culture with the contribution of anyone with good ears. He sees composers as the architects of sounds, although they seem not ready for the task. Finally, he argues for the acoustic designer to have training in acoustics, psychology, sociology, music, and more, although such schools do not exist and need to be created. Basic modules in such disciplines concern the human ear and the human voice, to know the world by experience and comprehend extrahuman sounds with respect to our own. Ear cleaning exercises is the name given to listening activities in support of the aural training process. Students should be engaged in recording practices, documenting their sounds, and exploring new places to notice variations which the familiarity with a place would not trigger. Sound and listening walks can support the aural training of the students, using maps as scores for the soundscape exploration.

In the chapter Acoustic Design, from the book Acoustic Communication, Truax argues that criteria for acoustic design are obtained from the analysis of positively functioning soundscapes. ⁶⁶ In addition to governmental legislation and consultants, listeners and sensitive experts can help supporting the goal in aiming at public awareness. The dualism between science and art is solved through the communication paradigm which describes the relationship of the individual and the environment as mediated by sound. Acoustic Design, therefore, ‘represents an understanding of the processes of acoustic communication and seeks to redirect the mediating influence of sound in relationships that are observed to be malfunctioning’.

Although for Schafer ‘any classification system or taxonomy is surrealistic’, he suggests that sounds can be classified according to their physical characteristics (acoustics), how they are perceived (psychoacoustics), focusing on their function and meaning (semiotics and semantics), or on their emotional or affective qualities (aesthetics) (p. 133). ⁶⁷ In explaining why this activity might be beneficial, Schafer cites Truax, for whom the act of ‘disintegrating a total sound impression into its component parameters’ is ‘a skill that must be learned’, probably necessary for acoustic design. In this quoted passage, Truax clearly reminds that ‘a soundscape cannot be understood merely by a catalogue of such parameters’, ‘but only through the representations formed mentally that function as a basis for memory, comparison, grouping, variation and intelligibility’. Before detailing how different classification approaches may help qualifying soundscapes, Schafer explains the aim of these comparison activities: ⁶⁷

If soundscape study is to develop as an interdiscipline, it will have to discover the missing interfaces and unite hitherto isolated studies in a bold new synergy. This task will not be accomplished by any one individual or group. It will only be accomplished by a new generation of artist-scientists trained in acoustic ecology and acoustic design.

Many classification systems have been proposed so far, one example being Krause’s ⁶⁸ division in Geophony, Biophony and Antropophony. The soundscape standard ISO 12913-2 ⁶⁹ Data collection and reporting requirements proposes a classification system which focuses on the Urban Acoustic Environment, based on the framework by Brown et al. ⁷⁰

From these two summaries, we can observe how the environment is considered as an ecosystem (an ecological system), in constant relationship with the listener. The listener, who can be considered an ever-learning open-minded and open-eared student, is invited to explore these relationships with the acoustic environment through a reflexive process which includes (1) exploration; (2) auditory observation; (3) the association with semantic constructs such as words; and (4) the documentation through the means available, including recording practices. The last step allows the experience gathered by the listener to be communicated to other human beings through further discussions which should include the perspectives of other social sciences to evaluate the perceived quality of the situations examined.

Developing acoustic ecologies

Being the founders of the acoustic ecology movement composers, soundscape composition further developed into a genre which is mainly constructed on sounds which preserve the features which make them recognisable.^71–73 However, the weight of the contribution of the WSP was also felt in other disciplines. Throughout the years, the development of the soundscape community was supported by the interdisciplinary contribution of cognitive and environmental psychologists and social sciences theorists. Discussions among researchers largely pointed to ecological themes and awareness motifs, adopting co-creation processes such as participatory mapping practices, often supported by an attention to psychoacoustics phenomena.^74,75

The concept of situation

The term situation is key in social psychology, arising in the literature with topological psychology from Lewin between the 1930s and 1940s. ¹²⁸ For Lewin, a person’s behaviour depends on two factors – the Person and the Environment – which together represent ‘one constellation of interdependent factors’. ¹²⁹ In 1981, Magnusson distinguished between ‘actual environments and situations’ and ‘perceived environments and situation’. ¹²⁸ From this concept derived situatedness, applied to the different but related fields of situated knowledges, situated practice, situated learning, and situating contexts (p. 4). ¹³⁰

Schön ¹³¹ defined reflection-in-action the phenomenon of reshaping design concepts during the process of designing, declined according to example cases. For the case of architects,

In a good process of design, this conversation with the situation is reflective. In answer to the situations back-talk, the designer reflects in action on the construction of the problem, the strategies of action, or the model of the phenomena, which have been implicit in his moves. ¹³¹

Situated knowledges

The concept of situated knowledges was introduced in 1988 by Donna Haraway, marking the particular, partial and embedded.^130,132 This process allows to ground knowledge with respect to where it is produced and historical contingencies, so that claims can be more aware of partial views and contradictions and keep looking for connections and compromises with other knowledge systems. For Haraway, knowledge is re-created through communities, rather than isolated individuals. ¹³⁰ In 1989, Brown et al. ¹³³ reflected on situated cognition in learning through concepts such as tools, enculturation, activity, apprenticeship, collaborative learning, studying examples from just plain folks (JPF), students and practitioners.

Situated learning

In 1991, Jean Lave and Etienne Wenger coined the term situated learning, locating this phenomenon in the capacity of learners to access participating roles in skilled performances.^130,134 For the authors, learning is a situated phenomenon since it takes place in a community of practice which allows ‘legitimate peripheral participation’, similar to apprenticeship.^130,134 Participation is legitimate since the integral role of the work in contributing to the practice is acknowledged by the community. Peripheral means that tasks are initially simple and intended as learning vehicles to appreciate the complexity of the whole work.^130,134

Clancey ¹³⁵ expanded this concept by arguing that situated learning is a theory ‘concerned with how learning occurs everyday’. The actions of us as individuals are situated in our role as community members and knowledge is dynamically constructed when what happens to ourselves is conceived within a social matrix influencing our thinking and behaviour. ¹³⁵

Situatedness in design

The concept of situatedness was later applied to design theories, science and practice. Gero ¹³⁶ argued that situatedness is concerned with the ability to contextualise so that both the situation and the situation’s construction or interpretation influence the decision-making process. Designers are seen as actors who operate within existing structural constraints, such as rules, discourses and artefacts.^130,137,138 To understand the extent to which design is situated, other methods can be invoked: (1) interdisciplinary methods, which help to understand the relationship between agency and structure; (2) methods to meta-design, aimed at improving healthy relationships with institutions or organisations; (3) reflective methods, to study how design approaches could be transferred to other domains. ¹³⁰

Architectural design education

Architectural design can be considered a form of situated knowledge, bound to geographical regions, legislation systems and locally established working practices. Let us now consider architectural design as a discipline interested in finding design solutions for specific settings and conditions, which we can call the design situation. Kowaltowski et al. ¹³⁹ highlighted how, in the context of architectural design education, the learning process mostly happens through the design studio, although the design process often does not follow rigid rules. At the basis of the design studio method there is the interaction of students with experienced professionals, allowing unstructured discussions to take place about design problems which are mostly specific and hypothetical. Kowaltowski et al. ¹³⁹ identified six main teaching methods for the design process:

From this list, we notice that designs and related problems are never generic, but specific, originated according to sites and typologies. Lawson ¹⁴⁰ found different approaches in design tasks between fifth-year student architects and fifth-year student scientists, with the former adopting solution focusing strategies and the latter adopting problem focusing strategies. Architectural design tasks often focus on the design of an original solution, and students are encouraged to justify their solutions, including formal ones. The adoption of CAD tools helps transfer ideas to a digital platform which allows further control on the properties of the design and its communication. From a creative standpoint, a common practice in architectural design teaching is metaphorical reasoning, defined by Welling ¹⁴¹ as four operations: application, analogy, combination and metaphor. ¹⁴² As found by Kowaltowski et al. ¹³⁹ in a worldwide and Brazil-focused survey, analogy is considered the most appropriate method to stimulate the designer’s creativity.

Acoustic design handbooks

A large number of courses teaching acoustics to student architects mimics the structure of handbooks of architectural acoustics. Templeton and Saunders ¹⁴³ include in their book Acoustic Design topics such as Perception of sound, Properties of sound, Sound in the built form, Noise control, and the last chapter called Design. The last chapter includes Buildings and Building Elements, such as roofs, ceilings, partitions, accompanied by design details and (outdated) UK Building Regulations.

Similar topics can be found in handbooks on architectural acoustics written in English.^144–149 Some publications have a deeper focus on auditoria,^9,21,150 and some others on modelling and design problems.^151,152 Often, these are directed also towards architects and pre-architects to support their design practice with guidelines accompanied by formulas, calculation procedures and example illustrations.

Among these, we can take as an example the handbook ‘Architectural Acoustics’ by Marshall Long. The book, designed to support the study of the subject for an introductory academic level, undergraduate or master, is organised as ‘a step-by-step progression through acoustic interactions’ with practical applications where appropriate. Algorithms are presented to solve real-life design problems and to understand the fundamentals. ¹⁴⁶

According to the chapter order in the book, the student shall start with the fundamentals, including the history of architectural acoustics, physical concepts and quantities, human perception (psychoacoustics), acoustic measurements, and environmental noise. After these five topics, we find a specialised chapter on wave acoustics, followed by eight different cases characterising sound propagation. Finally, we find six chapters on design cases (multifamily dwellings, office buildings, rooms for speech, rooms for music, multipurpose auditoria and sanctuaries, studios and listening rooms), interrupted in the middle by a chapter on sound reinforcement systems and followed by a chapter on computer simulation techniques.

From this overview, we can infer that the Acoustic Designer should fundamentally; (1) master the psychophysiology of hearing; (2) be knowledgeable about sound propagation; (3) understand the different acoustic requirements of common architectural spaces; and (4) be able to apply procedures to achieve acoustic design objectives. These can be considered the core pillars of the discipline regardless of the background of the aspirant designer.

In addition, there are several other topics which help to contextualise the discipline and its evolution. These topics are profoundly entangled with the development of the entire field of acoustics and an attention to sound in the design of the built environment. These can be (1) the historical development of the discipline, (2) the mathematical description of the propagation phenomena; (3) the design and control of electro-mechanical devices producing sound; (4) the design of technological elements able to show fine-tuned passive acoustic properties; and (5) the application of acoustic design knowledge to outdoor settings. Although these paths seem to diverge into many directions, an acoustic designer is expected to have a basic preparation also on each of these topics.

Documenting acoustic design education

The two main methods in acoustic design education could be identified as the analysis of existing settings and the design of new settings, based or followed in some cases by further analyses. The approach adopted by Berardi ¹⁵³ belongs to the first method. He reports emergent themes from his experience of teaching acoustics in an architecture school in Canada. He suggests that architecture students have limited attention since acoustics is perceived as an engineering discipline with strong bases into physics, and students consider the course distant from the architectural profession. He introduced new learning practices to help students ‘compare different sound spaces’, in addition to room acoustics descriptions through photos and graphs, and the visit to a performance space. These new practices consisted in the following:

Some other researchers have supported the adoption of smartphones in environmental acoustics education.^154–156 Kitapci ⁹⁰ followed a different approach and argued for a teaching module in interior design schools based on four phases addressing Schafer’s principles earlier mentioned: the technical lecture phase, the preliminary research and soundwalks phase, the initial design phase, and the holistic soundscape design phase. Kitapci ⁹⁰ motivates the criticism to existing courses stating that

the main objective of the design-oriented architectural acoustics course is to create awareness of the students in the built and natural soundscapes. It is also crucial to emphasize the relationship between conceptual ideas and auditory environments, while delivering adequate levels of theoretical knowledge comprehendible by interior architecture students.

Interesting crossovers were recently initiated by Llorca, looking at two aspects: (1) the potential that architecture students hold in drawing soundscapes ¹⁵⁷ and the evaluation of teaching methods for acoustic design through the bipolar ladder assessment (BLA).^158,159 Llorca et al. ¹⁵⁸ used the SketchUp plug-in RAVEN to provide an auralised listening experience to architecture students, after the delivery of a theoretical module on acoustics. Comparing theoretical teachings with the experience through the simulation software with the BLA method, Llorca et al. ¹⁵⁸ found that the students valued especially the change of paradigm from passive learning to learning by listening. The inclusion of this method for acoustic design teaching could therefore be valuable in architecture and building engineering curricula. They also stressed the importance of covering in an adequate way acoustic theory concepts. Another recent initiative aiming to conduct applied research at the intersection of architecture and acoustics is the European project Acoutect (http://www.acoutect.eu/).

In some cases, acoustic design educators adopt approaches borrowed from architectural acoustics and apply them to architectural design contexts. Trained students can be involved in acoustic surveying to build experiential knowledge based on their perceptions while enhancing observation and reporting skills. ¹⁶⁰ For example, Fowler ¹⁶¹ asked his landscape design students to record sonic excerpts from several sites, measure them and write notes in a diary. Students created visualisations of the resulting information on the geographical map showing the area explored, or on architectural drawings such as elevations, plans and sections.

Visualisations of interactions between direct sounds and reflections from architectural elements have been adopted also by Yang et al. ¹⁶² to show acoustic design rationales in Chinese listening pavilions. Schafer ⁶³ in general discourages the practice of reducing sound to sole visual signs, as he believes there is a perceptual abyss between a sonic experience and its graphical representation. However, he also acknowledges that visual representations and notation systems such as aerial sonography maps can make it easier for the inexperienced to absorb the salient information.

From aural architecture to architectural soundscapes

In the book Spaces Speak. Are you listening?, Blesser and Salter ¹⁶³ introduce the concept of aural architecture – spatial properties which can be experienced through listening. For these authors, the aural architect is usually not an individual but rather an ensemble of roles often unaware of their contributions towards our aural experience of a space, at times resembling the acoustic designer envisioned in Schafer’s and Truax’s words. Blesser and Salter ¹⁶³ distinguish the aural architect from the acoustic architect, who is rather a hybrid between the architect and the acoustic engineer.

The authors state that auditory spatial awareness is the fundamental skill that aspiring aural architects should develop through listening experiences and sonic practices. They further explain that three related disciplines are involved in investigations on auditory spatial awareness, creating methodological complexity through their combination. These are ‘physical science, which represents physical acoustics with mathematical equations; perceptual psychology, which describes perceptual acoustics with subjective measurements; and cultural anthropology, which understands cultural acoustics in phenomenological terms’. Following this triadic organisation, they argue that the experience of acoustics can be categorised in physical acoustics, perceptual acoustics and cultural acoustics. ¹⁶³

Access to education and resources

In developed research contexts, students can explore, through different methods, physical, technical, psychological and cultural aspects of acoustics and be taught how to design by taking into account acoustic properties of architectural environments. The positions of Harvey and Lacey enhance the need for acoustic ecology exercises in architectural design schools and acknowledge as fundamental the contribution from CRESSON’s researchers. The student is seen as a critical thinker able to playfully explore the sonic environment and conceptualise phenomena based on situated observations. A deeper attention to music is advocated by those practitioners who see potential in the exchanges between the arts though sound and space. The coverage of topics focusing on acoustic properties of materials, insulation and basics of reverberation seems available in some architectural schools with an engineering focus, embedded in either building physics or architecture technology courses, as shown by Berardi. ¹⁵³

Table 1 reports a list of educational settings showing the integration of sound-based studies within schools of architecture and design, from Harvey; ⁷⁹ Table 2 reports a list of acoustic courses in Canadian architectural schools, from Berardi; ¹⁵³ Table 3 reports a compiled list of acoustics departments, within or outside architecture schools, teaching acoustics or providing research supervision and equipment. Table 4 shows the contribution from Kitapci, ⁹⁰ who reviewed the teaching of acoustics within interior design courses in Turkey.

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Table 1.

Sound-based studies within schools of architecture and design, as reported by Harvey. ⁷⁹

	University	School/Department	Programme/Centre
FR	University of Grenoble	School of Architecture	CRESSON
CH	School of Polytechnic, Lausanne	Department of Architecture	Institut de Recherche sur l‘Environnement Construit (IREC)
US	Rensselaer Polytechnic, New York	Department of Architecture	Graduate programmes in Architectural Acoustics
AU	University of Sydney	Faculty of Architecture, Design and Planning	Master of Design Science (Audio and Acoustics) and single subjects
AU	University of Auckland	National Institute of Creative Arts and Industries	Acoustics Research Centre
UK	University of Edinburgh	School of Arts, Culture and Environment	Master in Sound Design and MSc/Dip in Sound Environments

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Table 2.

Acoustic courses in Canadian architectural schools as reported by Berardi. ¹⁵³

	University	Degree	Course
CA	University of British Columbia	Masters of Architecture	Architectural Technology II, Acoustics and Noise Control, Industrial and Environmental Acoustics and Vibration, Advanced Engineering Acoustics, Acoustics
CA	University of Waterloo	Bachelor of Architectural Studies	Interior Environments: Acoustics and Lighting
CA	Universite de Montreal	Bachelor of Science in Architecture	Lighting Engineering and Applied Acoustics
CA	Carleton University	Bachelor of Architecture	Theatre Production
CA	Dalhousie University	Master of Architecture	Acoustics
CA	McGill University	Master of Architecture	Environmental Acoustics
CA	Athabasca University	Post-Baccalaureate Diploma in Architecture	Architectural Design: Acoustics

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Table 3.

Acoustics research groups collaborating with architecture schools.

	University	School/Degree	Acoustics Research Group
UK	University of Liverpool	School of Architecture	Acoustics Research Unit
UK	University College London	Faculty of the Built Environment	Acoustics Group–Institute for Environmental Design and Engineering
UK	Sheffield	School of Architecture	Acoustics Group
DE	RWTH Aachen	Faculty of Architecture	Institute for Technical Acoustics
NL	Eindhoven University of Technology	Building Physics and Services	Building Acoustics
IT	Turin Polytechnic	Faculty of Architecture	DENERG – Department of Energy – Laboratory of Applied Acoustics
IT	University of Bologna	School of Engineering and Architecture	DIN: Acoustics Research Group
IT	University of Rome Sapienza	School of Engineering. Building Engineering Architecture	Department of Astronautic, Electric and Energetic Engineering: Acoustic Laboratory
IT	University of Campania Vanvitelli	Architecture and Industrial Design	Acustica, Vibrazioni e Interazioni Multisensoriali
BR	University of Campinas	Faculty of Civil Engineering, Architecture and Urbanism	LACAF: Laboratory of Applied Physics and Environmental Comfort
BR	Universidade Federal de Santa Maria	Engenharia Acústica	Grupo de Pesquisa Acústica
BR	Universidade de Sāo Paulo	Faculdade de Arquitetura e Urbanismo	Departamento de Tecnologia da Arquitetura

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Table 4.

Proposed acoustics course based on interior design studio course by Kitapci. ⁹⁰

Week	Proposed acoustics course structure	Interior design studio course structure	Traditional acoustics course structure
1	Introduction to architectural acoustics	Introduction to the course	Origins of sound theory
2	Research presentations	Research presentations	Fundamentals of acoustics
3	Soundwalks	Conceptual presentations	Human perception and reaction to sound
4	Studio critiques on the initial aural design ideas: keynotes	Studio critiques on the initial design ideas	Sound absorption
5	Studio critiques on the initial aural design ideas: keynotes	Studio critiques on the initial design ideas	Room acoustics I
6	Evaluation jury	Evaluation jury	Room acoustics II
7	Evaluation jury	Evaluation jury	Midterm
8	Studio critiques on the improved aural designs: signals	Studio critiques on the improved designs	Sound isolation
9	Studio critiques on the improved aural designs: soundmarks	Studio critiques on the improved designs	Mechanical system noise and vibration
10	Evaluation jury	Evaluation jury	Design of rooms for speech and music
11	Evaluation jury	Evaluation jury	National holiday
12	Studio critiques on the holistic soundscapes	Critiques on the detailed designs	Electronic sound systems
13	Studio critiques on the holistic soundscapes	Critiques on the detailed designs	Regulations, standards, and guidelines
14	Studio critiques on the holistic soundscapes	Critiques on the detailed designs	The soundscape theory
Final examinations

The teaching of soundscape-related themes, which could be beneficial in the development of the aural awareness needed to communicate with acousticians, for now is still limited geographically and in number of examples. To our knowledge, there is no dedicated master’s programme focusing only on soundscapes, which could bridge architectural design, acoustics and recording, and social sciences, mirroring the interdisciplinary school envisioned by the WSP. A solution adopted throughout the years is to connect schools from different countries through large-scale research projects, facilitating the exchange of knowledge. Examples are (1) ‘TD0804 – Soundscape of European Cities and Landscapes’ within the COST framework (European Cooperation in Sound and Technology); (2) ‘Hosanna – HOlistic and Sustainable Abatement of Noise by optimised combinations of Natural and Artificial means’; ¹⁶⁹ (3) ‘FP7 SONORUS – Urban Sound Planning’, aimed at discussing urban sound topics and training the new generation of researchers on urban acoustic design strategies.^170–173

The outcomes of these projects are applicable design guidelines which local authorities and spatial planners or designers can adopt.^174,175 Alves et al. ¹⁷⁶ provided a systematic review of European projects which address urban sound planning topics and an overview of research results that can be applied by practitioners. With the presence of acoustics groups in architecture schools, as – for example – in Sheffield,^{54,105,177–179} good research synergies seem to be activated, with valuable outcomes for the civic community.

Future directions

The efforts from the research community are already directed towards the amelioration of critical acoustic environments as well as the protection of positive ones which locals and planning authorities consider valuable and meaningful. Outcomes produced by the large-scale projects, which combine scientific acoustic research with the identification of design requirements and the development of design tools, could be better exploited if tested in planning contexts. In professional contexts, acoustic design intentions are always situated, being their accomplishment dependent on enforced regulations which guide professionals in guaranteeing acoustic comfort standards. Design decisions are taken every day in the communication between clients, acoustic consultants and architects, contextualised in a certain policy framework.

In the professional practice, the possible synergies between acoustic engineering and architectural design still seem rather unexplored. To reduce this academia–practice gap identified also by Aletta and Xiao, ¹⁸⁰ research outcomes need to be transformed into policies, so that design practices may become fruitfully effective in creating healthy sustainable environments and improving those which are perceived as critical. Reflective research methods should be invoked to investigate common practices in design environments and understand which rationales they follow. Studying professional acoustic design collaborations through qualitative methods may help understand what could be improved in the educational field, and from a regulatory perspective. Quantitative methods could in turn help study the impact on acoustic research centres on the development of acoustic design practices.