Jean-Paul Thibaud Cresson

Jean-Paul Thibaud
email: jean-paul.thibaud@grenoble.archi.fr

The sensory fabric of urban ambiances

the theory of urban ambiances, everyday perception in the urban environment, sensory culture and the ethnography of public spaces.

Introduction

The domain of urban ambiances has developed apace over the past twenty years*.

Disciplines as diverse as aesthetics, architecture, ethnography, environmental psychology, microsociology, cultural geography and urban studies introduced the idea of ambiance in order to describe and design the sensory fabric of the urban world more effectively. Ambiance cannot be simply assimilated within related concepts such as the environment, the landscape or physical comfort. Rather, it involves a socio-aesthetic approach that enables us to grasp everyday urban atmospheres. To put it in a nutshell, an ambiance can be provisionally defined as a space-time qualified from a sensory perspective. It appears as an alternative to bridge the sensitive, the spatial and the social domains.

Four main features specify this multidisciplinary research field. To begin with, the notion of ambiance postulates the unity of the senses. Hence, any ambiance involves all the senses at once (hearing, seeing, smelling, touching, tasting, moving…) and relies on a multisensorial experience. Secondly, any ambiance expresses an "affective tonality" that draws upon the sensibility of city dwellers. In other words, ambiance gives access to the various moods and emotional tones of urban life.

Thirdly, the ambiance research field tends to emancipate itself from normative approaches that aim to identify what is either annoying, comfortable or beautiful. It allows us to describe the whole spectrum of sensory experience without necessarily evaluating what is at stake (for example, to say that an ambiance has a climax or is steady does not mean that it is positive or negative). Finally, ambiance implements the transaction between the properties of the built environment and the lived experience of city dwellers. It asserts the activity of inhabitants and the role of social practices in the sensitising of urban world.

In brief, as soon as we attempt to define the notion of ambiance, we are inevitably confronted by the problem of perception. But what model for deciphering perception can be used to circumscribe and clarify the notion of ambiance? Conversely, in what respects do architectural and urban ambiances lead us to adopt new ways of addressing the issue of everyday perception? The aim of this paper is to highlight the close links between ambiance and perception. We shall seek to demonstrate that one of the key imperatives for the notion of ambiance is a reappraisal of the situational, sensory and practical character of perception.

1-Ambiance as the quality of a situation

We should start by pointing out that an ambiance-centric approach places the perceiver at the heart of the world he or she perceives and puts the emphasis on its all-encompassing nature, rather than any direct face-to-face relationship. (The word "ambiance" itself comes from the Latin ambire which means to surround or go around.) If the ambiance surrounds us, it necessarily results in "perception from the inside" and makes it difficult for the subject to step back and observe. As present-day parlance suggests, we may be part of the ambiance or we may feel it, but we cannot contemplate or observe it from a distance. In other words, ambiance puts us in immediate contact with an overall situation and consequently involves an ecological approach to perception. Perception cannot be dissociated from the concrete conditions in which it occurs. It is necessarily bound up with the built environment, sensory phenomena and the ongoing actions that render it possible. In short, in normal everyday life, when I perceive, I am always perceiving from somewhere, exposed to my surroundings and in the process of doing something. Far from being simply epiphenomena, these contextual dimensions are an integral part of perceptual activity. As a result, if we proceed in an exclusively analytical fashion, treating parameters consecutively -or indeed quite separately -we cannot grasp what makes a particular situation a consistent, unified whole. Having accepted this, not only do we need to recognise the heterogeneity of the conditions affecting perception, we must also ask how the various factors are integrated into everyday situations. How then are we to conceptualise the unity of a given situation? We contend that it is ambiance that blends and unifies the many components of a situation. It proceeds from an overall movement that gives each situation a specific appearance.

To develop this initial hypothesis we must start by specifying what we mean by situation. The philosophy of experience developed by John Dewey will guide us in this matter. Not only did he write extensively on this notion, but his aesthetics appears particularly relevant and useful for a theory of ambiances [START_REF] Thibaud | De la qualité diffuse aux ambiances urbaines[END_REF]).

According to Dewey, situations form the basic units of all types of experience and can be defined as the "environing experienced world". "What is designated by the word 'situation' is not a single object or event or set of events. For we never experience nor form judgments about objects and events in isolation, but only in connection with a contextual whole. This latter is what is called a 'situation' " (Dewey 1938: 66). A situation, therefore, cannot be reduced to a series of isolated or separable elements. It necessarily involves a unity that gives meaning to the whole.

Defining a situation in terms of the overall context raises the question of what unifies a situation. To answer this question Dewey introduced the notion of "pervasive quality" [START_REF] Dewey | Qualitative Thought[END_REF]). This notion is particularly important as it is bound up with the notion of ambiance. Indeed, it is perhaps another way of referring to ambiance. The three components used to define pervasive quality do certainly concern the notion of ambiance itself.

Quality as unity

First, for a situation to exist, all the components of a context must be integrated within a single quality, or else the experience would be lost in a series of confused, inconsistent perceptions. Empirical philosophy makes a distinction between primary (form, number, movement, solidity) and secondary qualities (colour, sound, smell, taste). But Dewey highlights what Santayana referred to as "tertiary qualities".

Whereas the first two categories refer to specific aspects of an experience, the third applies to the experience as a whole. In other words pervasive quality ties the components of a situation into a consistent whole and gives each situation a specific character. As Dewey describes it, any situation is both "qualitative" and "qualificative": qualitative in the sense that quality "constitutes in each situation an individual situation, indivisible and unduplicable"; qualificative in that the very same quality "penetrates and colours all the objects and events materially involved in the experience" (Dewey 1938: 68). This first point concerning pervasive quality could equally well apply to ambiance. An ambiance may be described using a single qualifier which does not apply to a specific component of the situation, but rather to the situation as a whole. We say that an ambiance is "happy" or "sad", "frightening" or "playful", "pleasant" or "depressing," and so on. From this perspective, the ambiance cannot be reduced to a sum of isolated objects, discrete signals, successive sensations or individual behaviour patterns. It unifies the situation and colours the environs.

Quality as mood

Secondly, pervasive quality is experienced in its immediacy, before being conceptualised or analysed. It consequently relates to the concrete character of the situation, the part we live and breathe. As such, knowledge of the experience matters less than the actual experience itself. By emphasising this distinction, Dewey rejects an overly intellectual approach that reduces reality to the object of knowledge or cognition. Pervasive quality involves the pre-reflective dimension of the experience, an intuitive way of grasping reality. In other words, this quality operates on a "lower level" than articulate language and is more a matter of comprehension than interpretation. It belongs to the realm of immediate feeling and bodily sensation and gives primacy to the aesthetic side of ordinary experience. Here again, this argument is reminiscent of what we might say about ambiance. In everyday language, we "experience" or "feel" an ambiance rather than "perceive" it. It is always charged with emotion. By placing us in a certain bodily and emotive disposition, it reminds us that perception is never disembodied or dispassionate. In other words, ambiance can under no circumstances be reduced to a simple act of interpretation. It confers value on what is perceived and expresses the prevailing emotional tonality. In addition, we sometimes say of an ambiance that it "gets inside us", or that we are "caught up in it". If an ambiance pervades a space, we can hardly localise or circumscribe it by assigning it a specific place and setting clearly identifiable limits. For example, although it is impossible to accurately circumscribe a fragrance or a warm area, this does not prevent us from feeling their environing presence. It is a diffuse presence that is perceived with varying degrees of intensity depending on what precedes and what follows it. In a nutshell, if ambiance relates to the immediate, pre-reflective character of experience, this is because it is invested with a logic of "vagueness" 1 that is very distinct from the logic that applies to the world of material objects.

Quality as a dynamic process

Thirdly, the qualitative character of the situation is fundamentally temporal and teleological. A situation represents the solution to a practical problem and must therefore be the subject of an inquiry, i.e., a process transforming a problematic or illdefined situation into one that is clearly defined. But the inquiry should not be seen as a strictly intellectual or cognitive activity. It is based on a series of perceptual actions and drivers (selection and configuration of the items relevant to the current action, adjustment and coordination of gestures, etc.). It initiates the transaction between an organism and its environment and must provide for the transition from an initial state of imbalance to a final state of balance. In this respect, pervasive quality is precisely what motivates the inquiry and gives internal consistency to the situation, conferring meaning and a clear direction. To paraphrase Dewey, the inquiry is the controlled or directed transformation of an indeterminate situation into a situation that is so determinate in its distinctions and constituent relations that it converts the components of the original situation into a unified whole. The original, indeterminate situation is not only "open" to inquiry, it is open to inquiry precisely because its constituent components do not hold together. In contrast, the determinate situation that marks the end of the inquiry is a situation, a closed and finite "world of experience" [START_REF] Dewey | Logic: The Theory of Inquiry[END_REF]. So pervasive quality is not only a question of passive reception but also involves a course of action. It is neither localised in the perceiver's organism nor in the objects of the environment, but applies to the situation itself, i.e., to a domain defined by the interaction between an organism and its environment.

As we shall explain in greater detail below, ambiance is related to the manner in which we act and behave. However, for the time being, we shall merely demonstrate that it also results from a dynamic that contributes to ongoing social activity. When we say that an ambiance is "setting in", "catching on", "in full flow", "breaking up" or "deteriorating", we are not only revealing its temporal character, but also stressing the fact that it emerges and develops in a certain way and in a certain direction. As such, an ambiance is not necessarily a stable and invariable state, but a dynamic process comprising different consecutive phases. But once again, the dynamic of the ambiance is part of an overall movement that expresses and conditions the way we behave and act collectively. Depending on the state of the ambiance at any given time, the situation will be more or less tense or relaxed, conflicted or consensual, problematic or straightforward. By shaping ongoing activities, the ambiance guides the manner in which a situation unfolds. The second part of the paper will discuss this point.

To sum up, this exposition of the theories of John Dewey has helped us formulate our first proposition regarding ambiance. Drawing on the notion of pervasive quality, we define ambiance as the quality of the situation. In this respect, perceiving does not just mean interpreting the world, it also involves integrating a situationthat is, it requires us both to pull the various components of a context into a consistent whole and to get involved in activities from a practical standpoint.

2-Ambiance as a motor stimulation

In this second section, we wish to emphasise that the perceiver is an actor in the world he or she perceives. Subjects are always engaged in situations that demand their attention and mobilise their action to a greater or lesser degree. Ambiance triggers a certain form of tension in the body that requires action and this underpins a praxeological approach to perception. Several recent publications explore this issue and attempt to pinpoint the close relationship between perception and action. In cognitive science there are those who see perception in terms of "simulation of action" [START_REF] Berthoz | The brain's sense of movement[END_REF] or "enaction" [START_REF] Varela | The embodied mind: Cognitive science and human experience[END_REF]. Ecological psychology advances the notion of "affordance" [START_REF] Gibson | The Ecological Approach to Visual Perception[END_REF]) to describe how the environment functions as a series of resources for action. Lastly, ethnomethodology focuses on "situated action" [START_REF] Suchman | Plans and situated actions[END_REF]) and defends the idea that each of our ways of perceiving has specific practical potential [START_REF] Coulter | The Praxiology of Perception: Visual Orientations and Practical Action[END_REF]. While the aforementioned authors are clearly working in very different fields, each contends that perception is closely linked to action and that it harnesses environmental properties. Furthermore, most of this research stresses the sensorimotor dimension of how we actually interact with the environment.

The capacity to act

But where does ambiance fit in here? How does it actually contribute to ongoing activities? To answer these questions, we should start by pointing out that ambiance affects our behaviour and bodily state. An ambiance may "stimulate" or "relax" us, "grab" us or "carry us away", "transport" or "paralyse" us, and so on. The use of verbs of this sort indicate that an ambiance is not just felt, it also involves movement. In other words, sensitivity and motility are two indissociable facets of the same phenomenon and neither predominates. In his sensory-tonic field theory, Kurt Goldstein demonstrated that for any sensorial impression there is a corresponding determined muscular tension [START_REF] Goldstein | The Organism: A Holistic Approach to Biology Derived from Pathological Data in Man[END_REF]. He identified what he referred to as "tonic phenomena" whereby we may consider ambiance as an energy system that is apparent through physical signals delivered by the environment and the tonicity of living creatures. Thus, there is no radical break between living creatures and their environment. In its way, ambiance reminds us that living organisms and their milieu form a continuum. Moreover, by claiming that ambiance corresponds to a certain state of muscular tension, we also contend that it affects our capacity for action. Some types of ambiancesuch as fairgrounds, major sporting events or night clubs are particularly stimulating. They are designed to plunge us into a state of tension and excitement that makes it impossible not to react. Other types of ambiancemuseums, churches, or hospitals, for exampletend to calm us down and are more conducive to contemplation and thought. Of course, these are extreme cases but they do show that an ambiance may increase or reduce our capacity for action by placing us in a particular physical and emotional state. Although we are used to considering action as one of existence's "givens", the notion of ambiance prompts us to ask what may instigate or neutralise action.

Styles of motility

We have just seen how ambiance is connected to practical activities, however, we need to clarify exactly what such a claim means. To do this we should start by pointing out that ambiance affects all sorts of actions. It concerns not so much the nature of the activity (the "what" of the action in the process of being accomplished) as its manner of execution (the "how" of the action, or the form it takes while being accomplished). By creating a state of muscular tension in the body, the ambiance gives rhythm to our movements and modulates the manner in which we move. In other words it drives action at its most elementary level, i.e., the physical gesture.

However, although gestures underpin actions they should not be confused with them.

Gestures are both functional (action) and formal (expression). Gestures not only enable us to accomplish actions, they accomplish them in a certain way. For example, the action of walking may take myriad different forms. One's step may be slow or quick, smooth or jerky, and so on. Yet these different styles of movement are not specific to this action -they may also apply to all sorts of other activities such as opening doors or going downstairs. The same action may take different forms and different actions may involve identical styles of movement. Does this mean that there is no consistency or logic to the manner in which an action is accomplished? One answer would be to look at the problem from a strictly individual standpoint. Every human being may be characterised by a specific way of moving. The bodily style which is particular to each of us could represent the subject's signature 2 . While this is an interesting proposition, it is hardly sufficient. If bodily styles were exclusively individual it would be difficult to envisage how they could coexist in the same space.

Once a place is frequented by several people, behaviour must be synchronised with a certain amount of mutual adjustment. There has to be a shared rhythm. So a second answer is needed and it involves looking at what is going on from a local and collective perspective. In other words, we shall assume that each ambiance corresponds to a style of motility and that this style is shared by all the participants involved in the ambiance. In this case, the manner in which we move would be affected by the place in which movement occurs. Our style of movement would express not only a "way of being" in a given environment but also a way of being together [START_REF] Merleau-Ponty | The Visible and the Invisible[END_REF]. Obviously, this does not mean that individual differences are erased or neutralised, but rather that they are part of an overall pattern of movement that cannot be merely reduced to the sum of its parts. So gestures and ambiance are consubstantial insofar as both confer ongoing action with a specific form. Both are part of the fit between "me", the world and others.

To sum up, introducing action into the ambiance equation leads us to a second proposition. We may now define ambiance as a motor stimulation in the sense that it activates sensorimotor processes through which we engage with the world. In this respect, perception cannot be reduced merely to passive contemplation of the world it involves moving in a certain way.

3-Ambiance as a sensory background

In the two preceding sections, we have attempted to provide a number of pointers concerning the relationship between ambiance and situation, and between ambiance and action. We shall now attempt to describe the relationship between ambiance and perception more closely. To do so we need to develop a phenomenological approach to perception. The value of this approach is that it highlights the sensitivity of perception and challenges the idea that perception is always about perceiving objects. So if perception is not merely an objectifying act that enables us to perceive the world as a set of separate, recognisable things, what is it?

The medium as the third term Challenging the notion of perception as a purely intellectual exercise does not necessarily involve adopting an empirical position that treats perception as the sum of discrete sensations. What we really need to clarify is the distinction between perception and feeling. The main argument developed in this final section is that ambiance is in no way an object of perception. Rather, we maintain that it establishes the terms of perception. In other words, we do not perceive the ambiance, we perceive on the basis of the ambiance.

We should start by stressing that the objects that we apprehend through perception are never separate, but always part of a relationship. They are always arranged one in relation to the other. One element may mask, or partially mask another. As the psychology of form has demonstrated, it is not so much isolated objects that we discern but rather configurations, articulated ensembles. But here again, objects affect the environment surrounding them. In a way, they radiate presence, projecting their qualities outwards and colouring the environs. It is sufficient to subtract or add an object in a particular place to realise that it does not just create or fill a vacuum. In some more fundamental way it changes what is there to be seen. We may substantiate this argument with the problems currently being encountered in research into simulating light ambiances. When virtual objects are embedded in photographs of real places, it is also necessary to factor in the light-related interaction that would inevitably occur in situ between the existing buildings and the new structures. But it is difficult to accurately calculate the "diffuse inter-reflection between surfaces" without which the final image would be quite unrealistic in terms of what a spectator would actually experience in situ [START_REF] Perrin | Simulation d'architectures en synthèse d'image[END_REF]. This brief digression into visionrelated research highlights the importance of the medium as a fundamental component in perception. Perceived objects always appear under certain lighting conditions and necessarily comprise a light structure that determines how they appear. James [START_REF] Gibson | The Ecological Approach to Visual Perception[END_REF] proposes the notion of an ambient optic array to analyse the manner in which a light field is structured. Even vision, the objectifying sense par excellence, cannot be understood without some reference to ambient light.

In fact, light constitutes a third term, forming a link between the perceiver and the world perceived. What we have just said about visual perception is even more applicable to other types of perception. Our perception of sounds, smells or temperature cannot be treated in the same way as that of a one-off source or a discrete signal. It always supposes a "sensing field" out of which phenomena emerge and take on specific properties. In brief, introducing the medium as the third term of perception enables us to conceptualise the perceptible world in terms of phenomena by revealing the conditions and manner in which they appear.

The basis for perception

Let us conclude by asking what is the consequence of the preceding argument? If ambiance can be distinguished from the world of objects it is precisely because it is bound up with the medium. This is why we talk about "luminous ambiances", "sound ambiances", "olfactory ambiances" or "thermal ambiances". These qualifiers refer to the nature of a medium but by characterising an ambiance in this way, we are also saying that it is not the ambiance that is perceived per se, but rather that it renders perception possible by specifying a "viewing field" [as above, do yiou mean :sensing field"?]in which these phenomena appear. We can never actually perceive everything that is encountered by our senses. As Merleau-Ponty demonstrated so clearly, "every perception is the perception of something solely by way of being at the same the relative imperception of a horizon or background which it implies but does not thematize" (Merleau-Ponty 1970: 4).

If the background is not perceived as such, it is precisely because it forms the basis for perception and the starting point from which phenomena and events assume individual and differentiable characteristics. This argument enables us to make a distinction between "perceiving this/that" and "perceiving on the basis of" [START_REF] Garelli | Voir ceci et voir selon[END_REF]). The first approach assumes perception of a determinate object by a perceiver.

Perception is conceptualised in transitive, one-off terms: transitive in the sense that a direct relationship is established between a subject and an object; one-off in the sense that what is perceived can be clearly identified, localised and circumscribed. In the second approach, the stress is on an attitude to something without presupposing any object to be perceived. Perception is conceptualised in intransitive and differential terms: intransitive in the sense that the medium acts as an intermediary term between object and subject; differential in the sense that the perceptible world is configured by the differentiation and tensions between its various components.

Obviously, in our opinion, ambiance is bound up with the whole background-related issue as defined by the second approach.

To sum up, this phenomenological approach to perception leads us to define ambiance as a sensory background that specifies the conditions under which phenomena emerge and appear. From this standpoint, perceiving involves not only discerning objects in the environment, but experiencing the state of the medium at a given time [START_REF] Böhme | An Aesthetics Theory of Nature: An Interim Report[END_REF].

Conclusion

Environmental and urban issues are key challenges in the contemporary world. To cope with them effectively, new conceptual tools and methodological frameworks have to be developed which foster original ways of dealing with day-to-day situations.

From this standpoint, the notion of ambiance implies a particular conception of situated perception that helps us to introduce and take on board the sensory, affective and material dimensions of the built environment. Such an experience-based model of the urban environment recognizes the complexity of the relationships between people and their surroundings by recognizing inhabitants as stakeholders, experienced citizens and sensitive subjects. Hence, a comprehensive approach is required that acknowledges the variety of ways in which city dwellers deal with and handle urban situations. In order to grasp one of the main epistemological implications of the notion of ambiance, it is necessary to bear in mind that it relies on a modal rather than a causal logic. The goal is not to develop a behaviorist or positivist approach to the built environment, but rather to describe as clearly as possible the forms, processes and conditions under which an urban experience occurs. In other words, the question is not "what" but "how", and not "what do people perceive?" but "how and under what conditions do people actually perceive the way they do?". This line of questioning opens up various avenues for research. One is to try to identify, characterize and classify various basic sensory phenomena that structure our ways of perceiving. This has been done extensively with the acoustic environment and the notion of sonic effect that draws upon scientific disciplines as diverse as applied acoustics, architecture, physiology of perception, sociology and aesthetics (Augoyard, Torgue 2006). Another approach is to harness the notion of ambiance as a tool to analyze and specify the sensory ecology of specific urban territories. For example, the study of urban underground ambiances reveals that these are particularly enveloping, over-stimulating, disorienting and restricting [START_REF] Chelkoff | Un nouvel objet d'ambiance: la ville souterraine[END_REF]. A third perspective explores the ways in which social practices and daily activities help generate an ambiance. Walking is the best and most widely documented example, which emphasizes the importance of improvisation in the sensory qualities of urban life (Thomas 2010). In other words, ambiances can be studied when focusing on the related sensory phenomena in accordance with the specific places or practical activities that they affect.

The field of urban ambiances also implies a reconsideration of everyday life. Most of the time, environmental research focuses on exceptional, extreme or borderline situations (that trigger urban safety measures, acoustic disturbances, air pollution, etc.). Of course, there are good reasons for this and resolving the most urgent problems is a priority. Nevertheless, this focus is only a small part of the whole picture and merely the most visible aspect of environmental issues. The ambiance approach enables us to enlarge the scope of environmental research by focusing on what lies beneath the "iceberg". What about everyday unnoticed environments, the ones we experience day in, day out in their most banal form without paying the least attention to them? Or, to put it differently, how does an ordinary ambiance become remarkable? Such questions are worth exploring and can provide new perspectives on environmental issues. After all, everyday situations are more significant than they seem. They form the basis of our ways of being in the world.

Finally, if the notion of ambiance can open new possibilities for studying the phenomenology of urban experiences, it can also help in the design and transformation of cities. Virtually all urban theories and current architectural projects need to take account of the sensory fabric of cities. Because the notion of ambiance helps to fit the physical within the social, the objective within the subjective, the sensitive within the practical, the perceived within the perceiver, it can prove particularly useful for architects and urban planners. At the juncture between quality of life, socio-economic urban strategies and current environmental issues, the notion of ambiance provides a new way of understanding and transforming the urban world. * I wish to thank David Howes for his thorough readings and pertinent suggestions for this paper.

Notes

1. For a discussion of vague logic, we refer the reader to the article by Charles Peirce (1878). If we follow Peirce's thinking, ambiance would undoubtedly be a part of "firstness", a category related to quality and feeling. Anne [START_REF] Cauquelin | Paysage et environs, une logique du vague[END_REF] applies vagueness logic to ambiance.

2. The cinema characters played by Charlie Chaplin or Jacques Tati are particularly striking in this respect.


The three dynamics of urban ambiances

Jean-Paul Thibaud

In Sites of Sound: Of Architecture and the Ear Vol. 2.

Brandon LaBelle & Claudia Martinho (eds.) Errant Bodies Press, Berlin, 2011, pp. 43-53 Urban space provides numerous ambiances to be felt with all the senses. Whether we think of a lively outdoor marketplace or a dull parking lot, an attractive historical center or a casual subway station, the very way we relate to those places is based on the sensory experience they involve. It is a matter of light and colour, sound, smell, touch and heat, and also the manner we walk and talk, move and look, relate and behave. Urban ambiances operate each time a subtle interweaving of synaesthesia and kinaesthesia occurs, as a complex mixture of sensation and movement.

To put it in a few words, an ambiance can be defined as a time-space qualified from a sensory point of view. It relates to the sensing and feeling of a place. Each ambiance involves a specific mood expressed in the material presence of things and embodied in the way of being of city dwellers. Thus, ambiance is both subjective and objective: it involves the lived experience of people as well as the built environment of the place.

How is it possible to account for the sensory variations of a public space? In what respect are urban ambiances to be described as a process of continuous creation? In what way do sounds and social practices contribute to sensitizing the urban experience? By exploring such questions I aim to reveal the way in which an ambiance emerges and disintegrates. Two considerations prompt these questions: first, urban ambiances are never laid down once and for all, rather they are constantly evolving, always in production; second, they cannot be dissociated from the situated activity of city-dwellers. In other words our hypothesis is that the notion of ambiance makes it possible to conceptualise the mutual determination of the built environment and social practice.

We should start by pointing out that urban ambiances cannot be reduced to a simple backdrop providing a framework for the activity of city-dwellers. If that was the case in situ perception would only evolve as a form of disconnected contemplation, based on the subject's withdrawal from their immediate environment. On the contrary, by endowing the urban space with particular properties and qualities, ambiances engage passers-by physically, connecting them to the site. As we shall see in due course, ambiances prompt forms of movement, expression and perception that are an essential part of our public conduct. Far from being simple epiphenomena of practical action, ambiances place activities in a context and invest situations at a sensory motor level. In other words the urban environment cannot be defined as a homogenous, neutral container into which various practices fit. On the contrary it is a heterogeneous ecological habitat that shapes practices, which in turn affect it.

Furthermore, city-dwellers may use the resources of a site to accomplish their activities, but the resources are much more than just a receptacle. The way people behave in public itself contributes to an ambiance in so far as it amplifies or neutralises certain sensory phenomena, exacerbating or altering certain properties of the built environment. As we can see from everyday language, people can at one and the same time "soak up" and "create" an ambiance. From this point of view the sensory contexts of a city are only partly based on the formal, physical characteristics of the built environment. Such considerations have serious consequences because they confirm the relative non-completion of ambiances given their strict spatial components and encourage us to draw conclusions based on the expressive power of bodies in motion and related social practices.

As I shall show below we may distinguish between three main dynamics involved in the creation of an ambiance. In the first case, ambiance emerges as the place is brought into tune with the conduct it supports. I refer to this as a "tuned ambiance" in the sense that the sensory phenomena reflect the close affinity that has developed between impressions and expressions, between what is felt and what is produced, between the subject and the world. In this case ambiance is thematized in terms of the Umwelt and engages an ecology of the lived world. In the second case, ambiance involves slight variations of the sensory context of the place. I call this a "modulated ambiance" in the sense that sensory phenomena fluctuate over time and diversify in line with activities. In this case ambiance is more akin to an updating of affordances and engages an ecology of situated perception. In the third case, ambiance may emerge through conditioning of the place by social practice itself. This I refer to as a "framed ambiance" in the sense that sensory phenomena are subjected to a formatting process arising out of the accomplishment of the actions underway. In this case, ambiance becomes primarily an instrument for giving shape to social situations and is consequently covered by an ecology of relations in public.

I should stress that these various processes do not refer to different types of ambiance but rather to the particular dynamics by which they emerge. In this sense they complement one another and always work simultaneously. The proposed distinction is therefore above all of a heuristic order. This distinction aims to clarify three basic ecological processes that constitute an ambiance, involving respectively tuning, modulating and formatting. It should also be noted that each of these processes involves specific domains of thought and conceptual tools. It is consequently necessary to bear in mind that the three regimes that I have identified relate to three overlapping points of view all relating to the notion of ambiance.

Acclimatisation : tuned ambiance

Acclimatisation refers to a process by which ambiance and conduct are brought into resonance, with the result that it is no longer possible to dissociate one from the other. In this case the activity of city-dwellers is tuned as much as possible to the sensory context of the place, simply expressing in its way the existing atmosphere. In a sense the public becomes the ambiance, and vice-versa. This fitting proceeds from an immediacy that leaves little room for a reflective attitude, because subject and environment merge so totally, vibrating in unison.

Feelings. The process of acclimatisation involves background feelings that may be thematized in terms of affectivity. From this point of view an ambiance cannot be reduced to a sum of physical signals, nor yet a succession of distinct phenomena depending on the sensory mode being considered. Ambiance is more a synergy between the senses that involves the emotional aspect of a situation. A quality of sound, light or fragrance is sensed in a single movement that confers unity on the sensory world. It should be stressed that these affective dispositions are distinct from the six basic emotional categories identified by Darwin (fear, anger, sadness, disgust, surprise, joy) in that most of the time they remain preconscious and often go unnoticed. It should also be noted that these impulses operate below the opposition between subject and object. They simultaneously involve a sense of self and the world.

For example in places saturated with all sorts of stimuli, the ambiance may be felt to be dizzying, depressing, alarming, disturbing or frightening. These qualifiers indicate the place's dominant quality as well as a rhythmic tension calling into play all the senses. In other words the subject does not so much pick up on a particular noise as on the alarming character of the sound environment, not so much the brightness of an object or surface as the disturbing aspect of the light environment, not so much the presence of a smell as the upsetting effect of the olfactive surroundings, etc. In so far as it contributes to the emotional tone, an ambiance does not apply to particular objects or stimuli, but rather colours the situation in its entirety. Phenomena are conjugated with one another to give an overall aspect to the space through which the subject is passing. The tendency to bustling activity and hurrying cannot be separated from feelings: the world is swarming, crawling with people in every direction, throbbing. Everything contributes to this excessive stimulation, to an overall tension, a sustained rhythm without it being possible to pin down a precise origin and clearly distinguish between the various phenomena.

In other places or on other occasions, the ambiance may be perceived as peaceful, restful, relaxing or tranquil. In this case an overall sense of unwinding is predominant, embodied in gentle lighting and filtered natural light, a subdued, sound environment, and relative freedom of movement and a slow gait, etc. Here again sensory phenomena overlap, joining up in a common rhythm that gives them a single tonality. Subjects experience a feeling of relief as they float, allow themselves to be lulled, immersed in or borne forward by the environment. Whereas the stressful atmosphere described above tends to be lived as a constraint, here we encounter an attitude of availability towards the surrounding world.

In short, we have here a form of receptiveness that links up with specific corporeal states and brings the senses into synergy. The two extreme cases we have just illustrated show that there are various ways of experiencing an atmosphere and being gripped by it. Obviously other types of context, no doubt more subtle in form, also trigger our propensity for being affected. Be that as it may, in their capacity as non-objectifying acts, that may be seen more as overall situations rather than finite objects, emotional tonalities seem to have a unifying effect on the various sensory registers.

Intercorporeity. Acclimatisation also involves the process of being-together that may be analysed in terms of "intercorporeity". It is here that the close entanglement of bodies comes into play, as if they were connected to each other by invisible, but very powerful threads. Individuals adopt shared rhythms and behaviour patterns, which may vary depending on circumstance and place. These common ways of being are based on collective forms of motivity.

In some cases the environment is so full of constraints that individual expression melts into and is diluted in a collective pool. Such dilution of identities occurs, for instance, when the subject can no longer hear their own sound output. Voices melt into the din, much as steps are drowned by the indistinct uproar. It is hard to tell who is producing what sound. Not only is human output all mixed up without any chance of differentiation, but human sounds may mix with mechanical noises too: the murmur of voices merges with the urban drone, the mass of conversations may be confused with the noise of a fountain or escalator, etc. Here, sonic ambiance defies any attempt to break it down into identifiable signals. It is more a sort of whole, a confused uproar or sound fog, leaving little room for single events or noticeable features. Similarly, at a kinaesthetic level the gestures of each person take part in an overall movement, driving each other. Crowd conditions thus tend to create a form of agitation from which the subject has difficulty escaping. In this case the imaginary of the milling and swarming expresses the relative lack of differentiation between individuals who move at more or less the same speed. The gestures of each person take part in an overall movement and drive one another. But more generally, social interaction can only occur if interpersonal behaviour is brought into phase.

The underlying mechanism of bodily adjustment consists in adapting one's conduct to suit local conditions and circumstances. Depending on where they are passers-by begin to whisper or, on the contrary, raise their voices. Some locations are places where one talks loudly, in others it is unthinkable to raise one's voice. It is as if the ambiance in question had to be extended collectively, as if some tacit injunction required the public to adjust its behaviour bringing it into line with that of others. In the same way urban spaces differentiate themselves by prompting different ways of walking. Some lend themselves to an ambling stroll, others are only fit to be crossed in haste. Passers-by vary their gait depending on the place in which they are, speeding up or slowing down, dragging their feet or walking briskly. They meander more or walk more gently when the tension drops or when time slows down. Whether we focus on sound output or the pace of movement, the problem may be posed in the same terms, the possible sharing of an embodied temporality. Or in other words, the rhythmic agreement that develops in a given ambiance is due to bodies being brought into temporal phase, permitting the existence of a common world.

Variation: modulated ambiance

Variation refers to city-dwellers power to modulate urban ambiances, which vary depending on how a place is used and occupied. Public perceptions and actions may be interpreted at two levels: on the one hand they are accomplished as a function of the affordances offered by the environment; on the other they have the power to activate or deactivate some of these resources. Paradoxically although whole swathes of literature have addressed the way the built environment makes action possible, very little work has looked at it as a medium by which inhabitants may express themselves. Accomplishing an action is based to a large extent on data provided by our surroundings, but we should not forget that this is not achieved without simultaneously modulating the framework on which action is based.

Territory. The built environment favours certain practices by offering them suitable supports, but the practices themselves change the environment's properties. Just compare a place when it is busy or deserted, and it is immediately apparent how much the physical presence of the public changes territorial structure. For example the way the public fans out over a space affects the scope for movement across it. A densely occupied space may force passers-by to slow down or perhaps even make a detour. Human presence configures the room available for movement by creating areas of varying fluidity or obstruction and setting a specific rhythm for the space being crossed.

Favourite meeting points temporarily organise a place's sound. A sudden cry or the murmur of the crowd, the shouts of children or applause, can give new depth to a space, making audible a source that is still out of sight. Depending on its location and the manner in which it propagates, such sound output, linked to ongoing activities, highlights the existence of certain areas to the detriment of others. The sound actions of the public provide clues to their presence, while at the same time revealing the spatial morphology of the site. In short the different ways in which we occupy and frequent a space impact on the sensory composition of the urban territory. The production of a sonic territory often involves two or more spaces overlapping. The sound atmosphere is not just here, in the immediate proximity, nor yet only over there, at a distance, but simultaneously here and over there. From this point of view the built environment may be defined in terms of material systems, which furnish resources for action, modifying practice at the same time as they are updated to suit the usages to which they lend themselves.

The activity of city-dwellers may be seen as filtering or amplifying the practical possibilities that a space affords. Affirming the public's capacity to modify the sensory amenities of a place goes hand-in-hand with recognition of the modular and circumstantial character of the built environment.

Details. As we shall see it often takes very little, almost nothing, to change an ambiance. What may seem a minor detail or an anecdotal phenomenon of no great importance is sometimes enough to qualify the whole of the sensory environment.

Walking provides a remarkable illustration of this point, because it provides a way of modifying most of a place's sensory qualities. In close relation to the overall morphology of the site the ground surface plays an essential role here. Its various propertiessmooth or rough, firm or soft, matt or reflective, absorbent or reverberating, etc.are updated in and by a visitor's movement. The ground does not only provide an affordance for walking, but also the material basis for various gaits, revealing itself in its relation to sound and light. Some surfaces encourage us to drag our feet or make us step cautiously. In other cases we stamp, stumble or slide more easily. The various ways of walking resonate differently and qualify the place sound-wise by giving it a specific rhythm and duration. A place is consequently not atemporal, coming alive thanks to both distinctive qualities of motion and sound. It should also be noted that some surfaces are more sonorous than others, reverberating more, making it easier for walkers to express themselves in sound. In this respect walking is more or less audible, depending on the place being traversed, with the ground and surroundings amplifying or dampening the sound of movement. Furthermore the manner in which the foot comes into contact with the ground depends on both the physical properties of the ground and the type of footwear. The body of the walker itself is endowed with attributes that play a part in modulating the sound atmosphere: stiletto or platform heels, for instance (but also wheelie suitcases or roller-skates, strollers or wheelchairs, etc.). Steps may crunch, squeak, click, scrape, rub, ring out or resonate. Sometimes footsteps produce an indistinct noise, a relatively continuous, dull murmur. In other cases they trigger unexpected events by revealing uneven patches of ground (a loose paving stone, a rocking manhole cover, etc.). They may even tell a story when each footfall is sufficiently clear for an observer to be able to follow a person's progress and visualize what is going on. Even if countless mechanical sounds invade the public arena in cities (escalators, fans, piped music), the lack of motor traffic in underground areas and pedestrian concourses helps to make footsteps stand out in the sound environment. The ground is thus an instrument of sound modulation in a place with which the public plays.

I have taken the ground as a paradigmatic example of the public's sensory variation. Other surfaces with which we come into contact, such as stairs or doors could be described in a similar way. Without going into detail, simply opening a door may reveal a view, add light, cause a draft, let in smells or sounds, etc. In any case, we should note that the material components of the space enable the public to modulate its sensory qualities with considerable subtlety. The tiniest detail of a built system may filter or neutralise the expressive force driving the activities underway.

Mark. The public does not often allow itself to be apprehended as an undifferentiated whole, as an indistinct mass investing an equally homogeneous space. Certain personal attributes and situated practices provide a way of making one's mark, of making a particular display or forming a distinct group.

Smells, smoke, heat and sounds are not only due to the built environment and its physical characteristics. They denote and express a human presence. The smell of perfume or cigarettes may mingle with others emerging from nearby shops. Smells tend to disappear into ventilation or air-conditioning systems or persist by impregnating fabrics, but they nevertheless sometimes emerge from the ambient environment. The trail left by a perfume or the area tainted by the smoke from a cigarette provide a sensory trace of past or present usage. Such traces, of varying evanescence or persistence, personality or anonymity, are the result of a place being used. But at the same time they requalify it. In the same way, heat varies as a function of a place's frequentation, a large number of bodies in movement generating a far from negligible output of calories. Whatever the scope for air circulation, a dense and lasting crowd tends to warm up a closed space and lend it a character it lacked earlier the same day.

Regarding sound, a child's shout fills a deserted, resonant place, exaggerating its presence, much as a group suddenly entering a square may produce a wave-like movement that reconfigures the whole of the sound space. In addition, though we demonstrated above that places tend to be embodied in shared rhythms, this is not always the case. It is enough for a single person to start running through a mass of slow-moving pedestrians, to falter and start looking for their way, or to stumble unexpectedly in the midst of the advancing crowd, for their presence to be noticeable and noticed. These little incidents or micro-events contribute to a place's ambiance, leaving room for improvisation and the unexpected.

Lastly some more or less spontaneous or ritual practices punctuate the atmosphere in public places. The increasingly frequent use of mobile phones, car drivers hooting their horns in celebration of a wedding, and even Saturday-night car-races are just a few examples of the sound events people may use to make their presence felt by others. Similarly the growing use of roller-blades, skateboards, push-bikes and other such wheeled devices significantly change the pace of contemporary urban spaces, enabling new categories of player to enter the arena. Increasingly equipped with roving technology citydwellers have access to new forms of ostentation and self-expression, which leave their imprint on the urban ambiance.

To sum up, making one's mark consists in leaving an imprint on the ambiance of a place, depositing a perceptible trace or behaving in a singular or unexpected manner. From this point of view an ambiance cannot be reduced to the sum of individual output or selfexpression. Rather it engages a continuous, back-and-forth movement between what is ordinary and what becomes remarkable. In this respect the micro-events of daily life serve as a reminder that at any moment an atmosphere may be requalified.

Alteration: framed ambiance

Alteration refers to the work done by the public to format a place's ambiance. The activity of passers-by is so powerful that it tends to form the main framework for this process. City-dwellers do not merely take advantage of the resources offered by a place, but reconfigure the sensory context on which they draw to complete their activities. In a way they produce the very conditions of their actions and transform ambiances into an essentially practical domain.

Field. Depending on how busy a space may be, the conditions of its perception may be affected. It is not so much the sensory qualities that are at issue here as the perceptible world itself, or in other words the scope for accessing, or not, wholly or in part, the surrounding space. More precisely human presence may affect the range of sight and hearing.

Reducing our field of perception and its reach impacts on sight and hearing. Regarding sound our access to distant sources is significantly reduced in a densely packed crowd (a demonstration, the rush-hour crush of pedestrians, busy city-centre shops or narrow streets, etc.). Not only do the bodies limit the propagation of signals over any appreciable distance by forming a screen, but, to an even greater extent, the noise produced (particularly voices and steps) by nearby people tends to drown out more remote sounds. In this case passers-by are immersed in a bath of sound, consisting primarily of scraps of conversation from the people following or preceding us, or coming the other way. In such a context it is above all the human presence and the sound output of the public that determines our range of hearing. Here, as in the case of sight, it seems impossible clearly to distinguish different planes or scales of perception.

Taking the measure of place consists in reconfiguring the spatiality of the place from a perceptive point of view. This concerns the materiality of bodies themselves and their capacity for acting as an obstacle to sight or hearing. Even if they pay particular attention passers-by suffer a restriction in their perceptive field, while at the same time being one of the main factors in this process.

Discernment. Passers-by use their senses to act and interact with others, but they must sometimes cope with problematic situations that cannot be grasped in their immediacy. Some of the information provided by the environment is perceived as incongruous, ambiguous or out of place. In this case the disparity between our perceptive expectations and the information actually received attracts our attention, obliging us to reframe it completely.

Such perceptive disturbances may be caused by the sound or visual environment, or more commonly by the separation of what we see and hear. At a visual level some reflections may multiply or invert views, producing optical illusions that are only resolved as we move forward. Contrary to what is usual, passers-by may see what is going on behind them, catch sight of bits of space upside-down or see the same object simultaneously from several points of view. In addition some light configurations may indicate a point of access that does not actually exist or give the mistaken impression that an exit exists. Passers-by thus tend to stray, only realising afterwards that they have been fooled by an illusion. With regard to sound some spaces are extremely ubiquitary, to such an extent that it is difficult to identify precisely the nature and origin of the sounds they are hearing. It is consequently difficult to rely on the sound environment to find their bearings or direct their course. Thought is required to solve this problem of interpretation. A double-take is sometimes necessary to check, and perhaps correct, their version. The various anamorphoses of the perceived space require the subject to make inferences, or deductions, testing all of their cognitive skills.

Difficulties often arise due to the disparity between what is seen and heard. For example only a few people seem to be visible, whereas many can be heard. Or on the contrary we may see a group of buskers busily playing and dancing, without being able to hear the music that accompanies their movement. In another instance a historic monument, of great importance as a symbolically and a part of our heritage, only produces insignificant, banal sounds, that seem mainly related to our private lives and much too familiar. Such sounds seem incongruous or out of place, in the sense that they relate to another context. In short there seems to be a mistake on the soundtrack. We are dealing with a form of dissonance between what is seen and heard, with the decontextualization of sound from its visual of reference.

Showing discernment involves making sense of the surrounding atmosphere despite the perceptive enigmas encountered. The work of framing carried out by passers-by makes it possible to give a common sense to a shared environment and continue using a public space together. In other words scenic intelligibility is a basic component of public life in that it makes it possible to maintain the self-evident nature of familiar features by finding solutions to perceptive discordances and practical problems.

Conclusion

We have seen that an ambiance emerges from a triple process: acclimatization, variation and alteration. These processes are always at work simultaneously in an ambiance but their respective power nevertheless varies from one atmosphere to another. Some ambiances lend themselves to change more than others, and are more amenable to variation and improvisation. It is a matter of greater or lesser contextual opening or closure, or in other words the relative capacity of an ambiance to integrate, exacerbate or neutralize the expressive power of social activities. For lack of a better term, perhaps we may speak of "contextual oscillation", the ability of an ambiance to polarize, balance or alternate various types of relation to our environment. Such result brings me to a few last remarks related to the built environment. It is obvious now that with architecture we cannot radically separate the material world from the immaterial one, the spatial forms from the temporal dynamics. Instead of speaking in terms of the beauty of an architectural object, I prefer to focus on the capacity of a built environment to intensify everyday experience and be responsive to its inhabitants. On the other side, architecture is animated, brought to life through our very ordinary actions, gestures and practices. It involves an aesthetics of engagement that is very much grounded on our sense of dwelling. To conclude on this never ending process of dwelling in the world, let me finish with the british social anthropologist Tim Ingold: "In dwelling in the world, we do not act upon it, or do things to it; rather we move along with it. Our actions do not transform the world, they are part and parcel of the world's transforming itself".


Jean-Paul Thibaud

Towards a praxiology of sound environment

In Sensory Studies

Online http://www.sensorystudies.org/sensorial-investigations/towards-a-praxiology-of-sound-environment/ Instead of dealing with the aesthetic aspects of the acoustic environment, the evolution of listening habits or cultural representations of urban noise, sound will be considered as a means for action and social practice. This paper tries to develop a praxiological approach to sound. To do so, two major obstacles must be overcome. On the one hand, it is necessary to challenge the three main socially recognized categories of sounds: music, speech and noise. Some fields of research have widened their domains or even reconsidered their basic premise in order to integrate certain phenomena previously neglected by the traditional scientific disciplines. We will convey that even if these new perspectives bring us closer to our daily experience of sounds, they still remain insufficient to fully account for sounding as acting. On the other hand, the pragmatic dimension of the acoustic environment has been largely under-estimated until now. Most research studies focus on symbolic, aesthetic or cultural aspects of audition, but very rarely recognizes it as a practical and contextual accomplishment. From this point of view, anthropology of everyday sounds could take advantage of what sociology of action and ecological psychology have to offer in this matter. It becomes more and more urgent to open the field of acoustics to the most recent results of human sciences. How is it possible to consider sounding as acting ? How does the acoustic environment afford and implement coordinated action ? What is the relationship between everyday sounds and ordinary practices ? These questions aim at overcoming a purely representational approach to the acoustic environment and raise a number of issues that can be briefly reviewed.

The heterogeneity of audition

The first issue pertains to the difficulty of considering all kinds of sounds, even those which seem valueless or insignificant. Acoustic ecology is mainly concerned with the perception, the composition and the characterization of soundscapes. The notion of soundscape, developed by Murray Schafer (1977), is one of the best attempts to challenge the distinction between everyday sounds and music, to recognize the importance of « sounds of little significance » and to analyze how they shape our ordinary audio culture. Nevertheless, by considering that the acoustic environment can be listened to as a musical composition, this fundamental shift in attitude towards everyday sounds tends to enhance a contemplative perception of the world and exclude other kinds of more practical listening (selective, focused, distracted, ect.).

Aesthetic conduct is only one of the diverse possible ways to relate to the environment. In everyday life, various modes of auditory orientation specify our attitude towards the audible world. Depending on the situation in which we are involved, we configure the surrounding one way or another: we can hear or listen, eavesdrop or heed, prick up our ears, notice or remark… Several classifications of listening have been suggested : Pierre [START_REF] Schaeffer | Traité des objets musicaux[END_REF] distinguishes listening from receiving, hearing and understanding, Barry Truax (1984) disassociates listening-insearch, listening-in-readiness and background-listening, Pascal [START_REF] Amphoux | Aux écoutes de la ville[END_REF] differentiates between the listening to the environment, milieu or soundscape.

If these basic categories can be very useful for analyzing the way we frame the audible world, are they discriminating enough to encompass the complexity and diversity of everyday situations ? What kinds of ordinary activities make the above ways of listening to the world possible? How and under what conditions do we manage to move from one type of listening to annoter ?

The affordances of the acoustic environment

The second issue involves acknowledging the pragmatic dimension of sound. Most research tends to evaluate the surroundings in physical, cultural or aesthetic terms without considering its practical significance. The acoustic environment is not ineffective regarding what people do here and now; rather, it affords, limits or prevents different types of activities. For example, street musicians know perfectly well that some places are more appropriate than others to play music and be best heard by the passers-by (subway corridors, reverberating places, junctions of galleries…). The theory of affordances, developed by James [START_REF] Gibson | The ecological approach to visual perception[END_REF], fully recognizes that perception is of practical layout, without reducing it to the mere conditioned-response behaviorism. From this perspective, perception consists in picking up information displayed by the environment in order to control actions (such as locomotion or manipulation). Thus, the environmental properties and the actor/perceiver activities cannot be disassociated, they shape eachother. As Gibson puts it: « an affordance is equally a fact of the environment and a fact of behavior ». This ecological approach to perception has been mainly devoted to vision but it can equally apply to audition. Nevertheless, the specificity of the acoustic environment cannot be too quickly disregarded. Auditory perception involves surroundability (i.e. sounds coming from everywhere) rather than frontality, dissemination (i.e. sounds separable from one to another) rather than contiguity, and instability of the figureground relationship [START_REF] Augoyard | La vue est-elle souveraine dans l'esthétique paysagère ?[END_REF].

If the field shapes of sound are to be considered as a resource for acting, how do these properties actualize in everyday activities ? Is it possible to differentiate and characterize various types of acoustic contexts according to the kinds of actions they afford ?

The embededness of sound in gesture

The third issue consists in reintroducing sound-making in everyday life. Usually, soundmaking is studied through professional and specialized practices. No doubt we have a lot to learn from musicians, sound-effects engineers or sound designers. However, we have also to admit that whatever we do and wherever we are, intentionally or not, we continually produce sounds. City dwellers are not only competent listeners of their environment, they also skillfully compose within it [START_REF] Augoyard | La production de l'environnement sonore[END_REF]. Nevertheless, only a few types of sounds are socially recognized in this matter: those intending to transmit explicit information (speech, a honk in traffic, applause to express contentement, a knock at the door before coming in, ect.). A whole range of soundful actions are completely neglected by laymen and scientific discourse. This does not mean that they are disinteresting, insignificant, and should not be explored as well. Furthermore, soundlistening and soundmaking are not two separate kinds of activities, they are closely intertwined through gesture. On the one hand, music for dancing, training, working or marching demontrates that sound stimulates body movement, enhances its rhythmic dimension and is to be heard with our whole body. In other words, listening requires our ability to orient ourselves towards the acoustic environment and move in accordance with it. On the other hand, gesture is the more basic means for producing sounds. Several possibilies can be distinguished depending on the level of control we have towards sounds and the degre of body involvement. First of all, we can make sounds directly with our own body: voice, hands, feet, ect. Before being speech, voice is first and foremost a sound gesture (Jousse, 1972). Similarly, feet cannot be reduced as merely a way of getting around, they are probably the most primitive means for producing sounds (Schaeffner, 1936). Secondly, we also make sounds in our use of and interaction with everyday life objects. In extending our bodily capacities, these manual devices produce sounds and provide acoustic information that help us to control in return the way we cope with the physical world (Norman, 1988). Thirdly, more automatic machines such as household appliances, audio equipment and electronic devices take part in the acoustic environment with minimun human intervention. Very elementary acts -to push a button, press or turn on a switch -can sometimes have tremedous effects on changes in the whole environment. Important differences characterize these three main situations. However, each of them involves some basic « body techniques » [START_REF] Mauss | Les techniques du corps[END_REF], motor skills that are inherent in our bodily capacities, technical equipment and socio-cultural background.

If soundful practices are very much related to our motion habits, is it possible to specify the basic gestures involved in the production of sound ? How do daily gestures embody the interaction between sound-listening and sound-making ? How is the acoustic environment organized according to the acquisition of common motor habilities ?

Sound as a feature of practical accomplishment

The fourth issue is to define a domain of research that fully recognizes ordinary practices of sound. Most of the time, sounds are treated as a mere epiphenomenon or secondary consequence of activity. Such an idea must be reconsidered. It is not only impossible to disassociate the acoustic environment from the activity in which the actor is engaged, but the former is to be considered as an essential feature of action. From this point of view, the acoustic environment is not given beforehand, « already there » and waiting to be heard by a disengaged listener, it is rather the product, expression and condition of social practices. We move from one problematic to another: the acoustic accompaniment of social activities to the practical accomplishment of the acoustic environment. In other words, we do not act in the acoustic environment but within it. Several research studies have already demonstrated the social efficiency of sounds. One of them points out that noise can foster various types of interpersonal communication [START_REF] Augoyard | La production de l'environnement sonore[END_REF], another one conveys that the acoustic environment of construction worksites is an essential feature of coordinated actions [START_REF] Thibaud | Temporalités sonores et interaction sociale[END_REF], and a third one argues that the various ways of using a Walkman can be considered as a means for sustaining new types of relations in public [START_REF] Thibaud | Les mobilisations de l'auditeur-baladeur : une sociabilité publicative[END_REF]. In one way or another, all these fieldwork studies elaborate on the relationship between sound and sociality. In order to elucidate « how we do things with sounds », it is necessary to recognize the phenomenological dimension of the social world, i.e. the way things show up for us and are accountable through our senses.

If sound is an essential feature of action, is there any social phenomena specifically embodied in this sensorial modalité ? What kinds of sonic performances maintain and implement the construction of the social world ?

The figure below briefly summarizes the four major arguments that have been presented.

Issues

Towards a praxiology of sound

The goal of this paper was to present a praxiological approach to sound. Although many questions that were raised were not answered, they could be used as a basis for building a research program. From a theoretical viewpoint, this approach purports to be an alternative of both cognitivism, which relies on « inner representations » to explain perception, and behaviorism, which emphasizes overt behavior from a very mechanistic point of view. Several methodological principles can help us to achieve such an approach. Sounds must be considered as a public account of the social world. They can be observed and described as an expression of the way we live together and share our common daily environment. An « ethnophony » of everyday life could be achieved by recording all kinds of ordinary soundful practices. However, in order to be properly analyzed, in situ recorded sounds must be ascribed to the context in which they were produced, i.e. the place and the circumstances in which they appeared.

Various techniques developed at CRESSON -« reactivated listening », « commented city walk », « conducted story », « recurrent observation » -offer a first account of this methodological issue (Grosjean and Thibaud, 2001). Furthermore, we also showed the complexity of real-world sonic phenomena by focusing on the heterogeneity of audition, the pragmatic dimension of the acoustic environment, the embededness of sound in gesture and the close relationship between sound and sociality. This complexity inevitably requires an interdisciplinary approach that integrates the physical, spatial, perceptual and social dimensions of sound. Of course, sounds can be described separetely from these various perspectives, but the major problem is to develop analytical tools that articulate them all together. The notions of « soundscape » (Schafer, op. cit.) and « sound effect » (Augoyard and Torgue, 1995) have already proved interesting to anybody studying or designing the acoustic environment. A further step would be to start projects that allow all sorts of sound professionals to work together and take advantage of their respective skills (acoustic engineers, social scientists, architects and sound designers). From this point of view, urban public space is a very resourceful domain that is worth exploring more carefully (Chelkoff, 1996). The pragmatic approach that has been presented may help us to overcome the traditional distinction between sound designers and researchers. They both have to take into account the way people perceive their daily environment and act within it. Probably, one of the major objectives of the next decade is to integrate the changes of modern life in the design of the acoustic environment. This requires being able to produce an environment that is both pleasant and hospitable, attractive and welcoming.