Papel de la variante Asn142Asp

The main use of soundscapes in a contemporary context, and the project this PhD came out of, is a way of understanding urban cityscapes from a quantitative acoustic perspective, with an emphasis on policy and planning. This body of research often has very direct aims: seeking comparisons between dierent environments of similar types, evaluating

urban public space, and generally aiming to end up with quantitative measurements of city spaces that can be used as best-practice or policy guidelines. This body of research uses the concept of soundscapes as a way to evaluate acoustic environments, using more than simply measures of loudness, which have historically been the methods employed. This body of knowledge generally uses quantitative methodologies, seeks to standardise responses, primarily measures spaces, and has an implicit goal of establishing standardised measurement tools.

This approach is needed, as despite the clear and demonstrable negative health eects of noise from stress to raised blood pressure (Adams et al., 2006), governments as a rule pay little attention to sounds: [French] parliament members [always prioritised] economic development concerns [. . . ] before environmental ones. Noise policies reach ninth place only, far after water control or water management (Raimbault and Dubois, 2005). Raising the prole of noise as an issue to be taken seriously by all governments then, is an important consideration.

These methods have their heritage in EU regulations (European Commission, 2002) on access to quiet space, which state: It is [. . . ] necessary to establish common assessment methods for `environmental noise' and a denition for `limit values', in terms of har- monised indicators for the determination of noise levels. The concrete gures of any limit values are to be determined by the Member States, taking into account, inter alia, the need to apply the principle of prevention in order to preserve quiet areas in agglomerations. (p13). Needless to say, this is rather vague. As Nilsson and Berglund (2006) point out though, absence of harmful noise does not [. . . ] guarantee a good sound environment. Therefore, current guidelines cannot be used to protect good soundscape quality in quiet areas. SPL1_{, therefore, is a poor guide to soundscape quality. Schulte-Fortkamp and}

Fiebig (2006) state this bluntly: [the SPL] approach turns out to have failed. The `Positive Soundscape Project' (PSP) summarise this shift.

In the acoustics community, sound in the environment, especially that made by

other people, has overwhelmingly been considered in negative terms, as both intrusive and undesirable. The (often tacit) goal of environmental acoustics could be stated as reducing the amount of sound to the lowest possible level. Numerous metrics have been developed to quantify unwanted sound over the last fty years, but in the last ten years there has been a gradual move in both legislation and research to standardise on some form of LAeq. A considerable

proportion of research and engineering eort in acoustics is expended on trying to reduce LAeq at the recipient's ears by means of: quieter transport (Oertli,

2006), ingenious noise barriers (Watts et al., 2004) and active control at the listener's head (Hansen, 2005), to take just a few examples. However, there is a growing sense that this eort is not producing wholly satisfying outcomes. The latest National Noise Incidence Study (BRE, 2002) shows that trac noise is audible at 87% of homes in England and Wales, and 54% of the population is exposed to levels beyond the World Health Organisation guidelines for avoiding serious annoyance. (Davies et al., 2007)

This school of research's quandary can be summarised. Solely loudness-measurement metrics are not working. Soundscapes cannot be judged based simply on the absence of negatives. How then, do we judge sound environments?

The increasing concern of noise annoyance in urban environment[s] has re- vealed the limits of physical descriptions to account for the subjective im- pression of acoustic phenomena, and suggest[s] a more cognitive approach to environmental sounds as meaningful events that aect people. Several authors have pointed to the limitations of acoustic parameters [. . . ] which cannot account for annoyance across dierent categories of noise sources. (Dubois et al., 2006, p865)

There has therefore been a shift towards research utilising semantic responses to acoustic environments. These studies, generally speaking, see the sound environment as an object- ive entity, which is now measured by taking measurements of the people within, instead of using a sound-level meter. There is also both an acknowledgement of, and a desire to move away from, what Schulte-Fortkamp et al. (2007) refer to as annoyance mapping. While mapping annoyances is more useful than mapping noises, it is also important that positive aspects can be recorded.

Recent research takes this approach to a logical conclusion: exploring how soundscapes can be altered to create more desirable places to be. Cain et al. (2013) for example demonstrate how a soundscape could be designed that is suitable for the activity within the chosen environment, and then how soundscape interventions could create a move towards this designed ideal soundscape. This is as yet untested but is a promising research avenue that would link lab testing to real-world interventions.