Decades of research support the idea that striving for lower sound levels is the cornerstone of protecting urban public health. Growing insight on urban soundscapes, however, highlights a more complex role of sound in public spaces, mediated by context, and the potential of soundscape interventions to contribute to the urban experience. We discuss Musikiosk, an unsupervised installation allowing users to play audio content from their own devices over publicly provided speakers. Deployed in the gazebo of a pocket park in Montreal (Parc du Portugal), in the summer of 2015, its effects over the quality of the public urban experience of park users were researched using a mixed methods approach, combining questionnaires, interviews, behavioral observations, and acoustic monitoring, as well as public outreach activities. An integrated analysis of results revealed positive outcomes both at the individual level (in terms of soundscape evaluations and mood benefits) and at the social level (in terms of increased interaction and lingering behaviors). The park was perceived as more pleasant and convivial for both users and non-users, and the perceived soundscape calmness and appropriateness were not affected. Musikiosk animated an underused section of the park without displacing existing users while promoting increased interaction and sharing, particularly of music. It also led to a strategy for interacting with both residents and city decision-makers on matters related to urban sound.

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Soundtracking the Public Space: Outcomes of the Musikiosk Soundscape Intervention.

Structure-borne low-frequency noise from multi-span bridges: A prediction method and spatial distribution

Based on subjective listening trials, Torija and Flindell [J. Acoust. Soc. Am. 135, 1–4 (2014)] observed that low frequency content in typical urban main road traffic noise appeared to make a smaller contribution to reported annoyance than might be inferred from its objective or physical dominance. This paper reports a more detailed study which was aimed at (i) identifying the difference in sound levels at which low frequency content becomes subjectively dominant over mid and high frequency content and (ii) investigating the relationship between loudness and annoyance under conditions where low frequency content is relatively more dominant, such as indoors where mid and high frequency content is reduced. The results suggested that differences of at least +30 dB between the low frequency and the mid/high frequency content are needed for changes in low frequency content to have as much subjective effect as equivalent changes in mid and high frequency content. This suggests that common criticisms of the A-frequency weighting based on a hypothesized excessive downweighting of the low frequency content may be relatively unfounded in this application area.

The subjective effect of low frequency content in road traffic noise

It is a one-sided preconception that living in a city is necessarily associated with unbearable noise exposure. The observed variation of noise exposure in cities is quite large and you can find quiet residential areas as well. However, in megacities, the background sound level—“the city hum”—is usually louder due to the multitude of city sound sources. The large variation in noise levels is determined by the cumulative effect of unfavorable or thoughtful city design elements at several scales of a city’s general and neighborhood layout. This comprises several scales of planning: the transportation system, the city and building structure, population density, the design of street and building facades, the amount of green space, and the quality of the dwellings with respect to sound and vibration features. The favorable and unfavorable features differ between European, Asian, North and South American and African cities of any size and contribute to more or less health.

Noise in Cities: Urban and Transport Planning Determinants and Health in Cities

Model development for traffic noise annoyance prediction

Adjustment on subjective annoyance of low frequency noise by adding additional sound

In order to control railway noise pollution in urban areas, the residential district located near the Zhegan railway in Hangzhou urban was taken for example, and some controlling measures were proposed based on the investigation in railway noise impact as well as the planning of the district, the environmental scene and the project devises. The measures included setting man-made soil slopes, noise barriers and virescence. Combining some of them could be a typical noise reduction scheme. The professional software Cadna/A was used to predict the noise reduction results of every scheme. Results show that the maximal difference of noise reduction is 19.4 dB and the noise reduction effect of the second scheme is best. However, if only railway noise influence is considered, the first scheme is best. The research results can provide reference for residential districts planning and noise control near the railway in urban areas.

Zheng-guang Li

Papers

Adjustment on subjective annoyance of low frequency noise by adding additional sound

Optimally control urban railway noise by sound propagation path