Speaker discrimination in multisource environments auralized in real rooms

With the recent development of audio in modern VR/AR systems and the increasing capability of synthesizing natural sound fields over headphones with head tracking, the question of the ability of our hearing system to discriminate multiple concurrent sound sources has become important again. We must understand how psychoacoustical and psychophysical limitations of the hearing system cope with novel technologies of virtual acoustics that can simulate an almost unlimited number of sound sources. Previous research has shown that the capacity of human hearing to discriminate a reference sound source is limited when there is background noise, a reverberant surrounding, or when other, disturbing sound sources simultaneously mask the reference source. A set of listening tests based on the cocktail-party effect was designed to determine the intelligibility of speech emitted by a reference sound source, with one to six disturbing sound sources simultaneously emitting speech from different directions around the listener. The tests were repeated in three test rooms with different acoustical properties, and two test signals were used: logatomes and regular spoken sen-tences with specific keywords. The results have revealed the changes in speech intelligibility scores in relation to the number of disturbing sources, their positions, and acoustical properties of test rooms

Collecting and mapping soundscape data across the 15 UK National Parks

The soundscape approach, as understood by the ISO 12913 series, is most applied in urban settings, aiming beyond noise control in order to holistically employ its quantitative and qualitative facets. On the other side, the current understanding of the soundscape concept in bioacoustics and acoustic ecology is less focused on perception. There is generally a lot of public interest in how to preserve the opportunity for people to experience the “natural quiet” and “the sounds of nature”, and the need to balance that with the protection of the natural areas and national parks from the noise that the visitors themselves generate while on site. However, specific investigations in these environments are scarce in the United Kingdom. Moreover, while there might be acoustic environments and sound sources that people identify with national parks, they are not systematically documented nor implemented in the national parks' management plans. Therefore, we propose a framework starting with a quasi-crowd-sourced acquisition of soundscape data and mapping those to a freely accessible GIS platform such as Google Earth, leading towards identifying soundscape conservation targets and management tools for the UK national parks, further raising the awareness of the value of sound as a resource

Increases in noise complaints during the COVID-19 lockdown in Spring 2020: A case study in Greater London, UK

Many cities around the world have claimed that the enforcement of lockdown measures to contain the spread of COVID-19 and the corresponding limitations of human activities led to reduced environmental noise levels. However, noise complaints reported by many local authorities were on the rise soon after the local lockdowns came into force. This research took Greater London in the UK as a case study. The overall aim was examining how noise complaints changed during the first stages of the lockdown implementation, during Spring 2020, both locally and at city scale, and how urban factors may have been influencing them. Noise complaint and urban factor datasets from the Government's publicly available data warehouse were used. The results show that during the COVID-19 lockdown the number of noise complaints increased by 48%, compared with the same period during Spring 2019. In terms of noise sources, complaints about construction (36%) and neighbourhood (50%) noise showed significant increases. Urban factors, including housing and demographic factors, played a more significant role than the actual noise exposure to road and rail traffic noise, as derived from the London noise maps. In detail, the change rate of noise complaints was higher in areas with higher unemployment rates, more residents with no qualifications, and lower house price. It is expected that this study could help government with allocating resources more effectively and achieve a better urban environment

Ecological Validity of Immersive Virtual Reality (IVR) Techniques for the Perception of Urban Sound Environments

Immersive Virtual Reality (IVR) is a simulated technology used to deliver multisensory information to people under different environmental conditions. When IVR is generally applied in urban planning and soundscape research, it reveals attractive possibilities for the assessment of urban sound environments with higher immersion for human participation. In virtual sound environments, various topics and measures are designed to collect subjective responses from participants under simulated laboratory conditions. Soundscape or noise assessment studies during virtual experiences adopt an evaluation approach similar to in situ methods. This paper aims to review the approaches that are utilized to assess the ecological validity of IVR for the perception of urban sound environments and the necessary technologies during audio–visual reproduction to establish a dynamic IVR experience that ensures ecological validity. The review shows that, through the use of laboratory tests including subjective response surveys, cognitive performance tests and physiological responses, the ecological validity of IVR can be assessed for the perception of urban sound environments. The reproduction system with head-tracking functions synchronizing spatial audio and visual stimuli (e.g., head-mounted displays (HMDs) with first-order Ambisonics (FOA)-tracked binaural playback) represents the prevailing trend to achieve high ecological validity. These studies potentially contribute to the outcomes of a normalized evaluation framework for subjective soundscape and noise assessments in virtual environment

Using Virtual Soundwalk Approach for Assessing Sound Art Soundscape Interventions in Public Spaces

This paper discusses the soundscape assessment approaches to soundscape interventions with musical features introduced to public spaces as permanent sound art, with a focus on the ISO 12913 series, Method A for data collection applied in a laboratory study. Three soundscape interventions in three cities are investigated. The virtual soundwalk is used to combine the benefits of the on-site and laboratory settings. Two measurement points per location were recorded—one at a position where the intervention was clearly perceptible, the other further away to serve as a baseline condition. The participants (N = 44) were exposed to acoustic environments (N = 6) recorded using the first-order Ambisonics microphone on-site and then reproduced via the second-order Ambisonics system in laboratory. A series of rank-based Kruskal–Wallis tests were performed on the results of the subjective responses. Results revealed a statistically significant positive effect on soundscape at two locations, and limitations related to sound source identification due to cultural factors and geometrical configuration of the public space at one location

Late results of surgical and medical therapy for patients with coronary artery disease and depressed left ventricular function

Late survival and freedom from myocardial infarction were determined for 192 patients with coronary artery disease and depressed left ventricular ejection fraction at rest (<35%) determined by biplane angiography who were evaluated between 1970 and 1977. Seventy-seven patients had coronary artery bypass grafting and 115 patients were treated medically and were considered surgical candidates. The medical and surgical groups were comparable in all baseline characteristics examined except frequency of three vessel disease and angina pectoris, which occurred in a significantly greater percent of the surgically treated patients (p < 0.01). Only three medically treated patients (2.6%) underwent coronary bypass grafting in the follow-up period.Seven year actuarial survival was 63% in the surgical and 34% in the medical group (p < 0.001). Ninety-three percent of patients in the surgical group and 81% of those in the medical group were free of nonfatal myocardial infarction (p = 0.01), and 62 and 33%, respectively, were alive and free of myocardial infarction (p < 0.001) at 7 years. Significant differences in survival favoring surgical treatment were observed for the subsets of patients with an ejection fraction of 25% or less (p = 0.0002) and 26 to 35% (p = 0.01), and for the subsets with three vessel coronary disease (p < 0.001), normal left ventricular end-diastolic volume (<100 ml/m2) (p = 0.005) and elevated end-diastolic volume (>100 ml/m2)(p = 0.001). After adjustment for other important prognostic variables, the type of treatment remained significant in predicting the relative risk (medical to surgical) of mortality at 5 and 7 years (2.58 and 2.12, respectively).These data corroborate the trends observed in several randomized trials of medical and surgical therapy in patients with abnormal left ventricular function. If hospital mortality for coronary artery bypass grafting is less than 5%, substantial benefit can be anticipated for the majority of patients with depressed ventricular function

Acoustic Design Criteria in Naturally Ventilated Residential Buildings: New Research Perspectives by Applying the Indoor Soundscape Approach

The indoor-outdoor connection provided by ventilation openings has been so far a limiting factor in the use of natural ventilation (NV), due to the apparent conflict between ventilation needs and the intrusion of external noise. This limiting factor impedes naturally ventilated buildings meeting the acoustic criteria set by standards and rating protocols, which are reviewed in this paper for residential buildings. The criteria reflect a general effort to minimize noise annoyance by reducing indoor sound levels, typically without a distinction based on a ventilation strategy. Research has developed a number of solutions, discussed here, that try to guarantee ventilation without compromising façade noise insulation, but, currently, none have been adopted on a large scale. This concept paper highlights the main limits of the current approach. First, a fragmented view towards indoor environmental quality has not included consideration of the following acoustic criteria: (i) how buildings are designed and operated to meet multiple needs other than acoustical ones (e.g., ventilation, visual, and cooling needs) and (ii) how people respond to multiple simultaneous environmental factors. Secondly, the lack of a perceptual perspective has led acoustic criteria to neglect the multiple cognitive and behavioral factors impinging on comfort in naturally ventilated houses. Indeed, factors such as the connection with the outside and the sense of control over one’s environment may induce “adaptive acoustic comfort” opportunities that are worth investigating. The mere use of different sound level limits would not be enough to define criteria tailored to the complex user–building interaction that occurs under NV conditions. More holistic and human-centered approaches are required to guarantee not only neutrally but even positively perceived indoor acoustic environments. For this reason, this paper considers this apparent conflict from a soundscape viewpoint, in order to expose still unexplored lines of research. By underpinning a perceptual perspective and by contextualizing it, the indoor soundscape approach provides a framework capable of overcoming the limits of the traditional noise control approach. This could provide the opportunity to foster a wider adoption of NV as a passive design strategy that enhances user health and well-being, while enabling low-cost, and low-energy cooling and ventilation, thereby contributing to current climate change challenge

Associations between indoor soundscapes, building services and window opening behaviour during the COVID-19 lockdown

Results of an online survey conducted during the COVID-19 lockdown among 848 home workers living in London (United Kingdom) and in Italy are reported with a focus on (1) the impacts of building services on the perception of the acoustic environment while working and relaxing at home and (2) the factors associated with window opening behaviour. The analyses showed no significant difference in soundscape appropriateness for relaxation depending on the heating, ventilation and cooling system typologies, and in soundscape appropriateness for working from home (WFH) based on the ventilation strategy. Higher soundscape appropriateness for WFH was associated with houses equipped only with radiant floors for heating in Italy and with air-cooling systems in London. In London, air systems resulted in higher perceived dominance of noise from building services compared to other systems. Overall, rooms with less dominant sounds from building services were evaluated as more appropriate for working and relaxing. The dominance of sky or buildings from the window view, outdoor noisiness, noise sensitivity, age and gender were not significantly associated with participants’ window opening behaviour while WFH. Differently, participants viewing more vegetation from windows in Italy were more likely (odds ratio: 1.279) to keep the window open while WFH

Analysing the Changes in Physiological Response to Different Soundscape Scenarios

Noise pollution is one of the key environmental stressors leading to multiple health impacts for people and communities. Exposure to high noise levels may also be responsible for sudden emotional and physiological changes in humans. The experiment examines the change in Galvanic Skin Response (GSR) signals during exposure to pre-recorded soundscape scenarios. These scenarios were recorded in New Delhi, India and London, UK, using a binaural microphone set. The listening experiment was conducted in a laboratory, where 27 healthy individuals without any hearing impairment or any psychological issues participated. A total of 30 soundscape scenarios were presented to each participant in a randomised order. The continuous decomposition analysis is conducted to decompose that data into tonic and phasic components. The phasic component of the signal is used for the analysis. It is observed that skin conductance response increases with changes in eventfulness of the signal (P<0.05). The pleasantness of the signals has not shown a statistically significant relationship with the change in skin conductance response