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Abstract The effects of indoor water sounds on traffic noise perception were investigated under three room temperatures of 18 °C, 24 °C, and 30 °C through listening experiments with 54 participants. Two types and four levels of water sounds (35, 40, 45, and 50 dBA) were presented with four levels of traffic noise (45, 50, 55, and 60 dBA) in an indoor environmental test laboratory. Water sounds were recorded using a simple indoor fountain comprising a submersible pump and two types of nozzles (foam-jet and mushroom), which generated different water sound spectra. The listeners assessed the thermal and acoustic environments on eleven adjective attributes, representing negative acoustic attributes, positive acoustic attributes, acoustic comfort, thermal comfort, and overall comfort. The results showed that indoor water sounds enhanced pleasantness, calmness, and naturalness without increment of noisiness, loudness, or annoyance in the 30 °C condition, while no perceptual improvement of traffic noise was found in the 18 °C and 24 °C conditions. Room temperature affected both thermal perception and acoustic perception. Water sounds affected not only acoustic perception, but also thermal and overall indoor environmental comfort. A just noticeable water sound level was preferred to mitigate intrusive traffic noise perceptually in a room. The noise perceived in a room should be described by both negative and positive adjectives together, in order to evaluate the effects of indoor environment, such as water sounds and temperature, on noise perception. [ABSTRACT FROM AUTHOR]

Abstract Cross-modal effects of sound and illuminance were investigated in an indoor environmental chamber with 60 university students (30 men and 30 women) aged 18–26 years. A within-subject factorial design was employed with four independent variables: noise level (45, 55, 65, and 75 dBA), noise type (Music, Water, Babble, and Fan), illuminance level (150, 500, and 1000 lx), and sex (female or male). The test conditions represented daily indoor environments, which was moderately noisy and did not present severe lighting conditions. Acoustic (loudness, annoyance, pleasantness, and naturalness) and visual (brightness and relaxation) semantic attributes were assessed using an 11-point numeric scale. The illuminance level of the ambient lighting system did not affect acoustic perception. Brightness was not altered by sound, but relaxation was affected by sound. Cross-modal interactions were asymmetric between sound and illuminance in indoor environmental settings. Women were more sensitive to the perception of both acoustic and illuminance stimuli than men, at high level of stimulation. [ABSTRACT FROM AUTHOR]

The sound environment and acoustic perception of open-air markets, which are very common in high-density urban open spaces, play important roles in terms of the urban soundscape. Based on objective and subjective measurements of a typical temporary open-air market in Harbin city, China, the effects of the temporary open-air market on the sound environment and acoustic perception were studied, considering different crowd densities. It was observed that a temporary open-air market without zoning increases the sound pressure level and subjective loudness by 2.4 dBA and 0.21 dBA, respectively, compared to the absence of a temporary market. Different from the sound pressure level and subjective loudness, the relationship between crowd density and the perceived acoustic comfort is parabolic. Regarding the effect of a temporary open-air market with different zones on the sound environment and acoustic perception, when the crowd densities were the same, subjective loudness in the fruit and vegetable sales area was always higher than in the food sales area and the clothing sales area. In terms of acoustic comfort, with an increase in crowd density, acoustic comfort in the fruit and vegetable sales area decreased, and acoustic comfort in the food sales area and the clothing sales area exhibited a parabolic change trend of increase followed by decrease. Overall, acoustic comfort can be effectively improved by better planning temporary open-air markets in high-density urban open spaces. [ABSTRACT FROM AUTHOR]

The acoustic environment of restaurants is important for diners. Based on acoustic measurements and a questionnaire survey of typical restaurants, differences in diners' conversation behaviour and acoustic perception were analysed. Three dining styles were compared (centralized, separate, and dispersed), and crowd density and background music were considered. Several interesting findings were gained. First, dining styles affected conversation behaviour. When there were four or more diners per table, conversation increased compared to when there were three or fewer; and background music did not reduce conversation. With the centralized style, the proportion of speech diners heard was greater than for the other two dining styles, even as crowd density increased. Second, dining styles affected sound pressure level. With background music, the separate style decreased sound pressure level more effectively than the other two styles when crowd density was low, and without background music, the separate style decreased sound pressure level more effectively than the other two dining styles irrespective of crowd density. Dining styles also affected acoustic comfort: with the centralized and separate styles, acoustic comfort took on a parabolic shape, first increasing and then decreasing as crowd density increased, while with the dispersed style, as crowd density increased, the acoustic comfort of diners decreased. [ABSTRACT FROM AUTHOR]

Stress is known to elicit various adaptive or maladaptive responses in the nervous system function. Psychophysical studies have revealed that stress exposure induced the changes in auditory response that can be interpreted as a transient, stress-induced hypersensitivity to sounds. However, the underlying neural mechanism remains unresolved. Thus, in this study, we explored the neural activities of the auditory cortex (AC) in response to stress. We elicited stress by physically immobilizing rats and recorded the extracellular single-unit activities through the electrodes chronically implanted in the AC of rats. By comparing the spike activities of the same rat before, during and after immobilization, we found temporal and significant changes in the sound-evoked neural activities. In most cases, acute restraint stress enhanced neural responses evoked by pure-tones and click-trains, but in a minority of neurons, stress suppressed responses. The immobilization-induced enhancement was more frequently found in the neurons that originally had a low responsibility for sound stimuli. The enhancement effects on pure-tone response were reflected by an increase of response magnitude, decrease of response latency, and extension of bandwidth of tuning curve (BW). But the spontaneous firing rate and best frequency (BF) remained unchanged. Stress also increased the ability of neural response to synchronize to click-trains, even in the neurons whose response magnitude was not significantly increased. Taken together, these results provide direct evidence that stress alters the function of auditory system at the level of AC. [ABSTRACT FROM AUTHOR]

Abstract: Understanding the physiological role of the auditory cortex (AC) in acoustic perception is an essential issue in auditory neuroscience. By comparing sound discrimination behaviors in animals before and after AC lesion, many studies have demonstrated that AC is necessary for the perceptual process of human vowels and animal vocalizations, but is not necessary to discriminate simple acoustic parameters such as sound onset, intensity and duration. Because a lesion study cannot fully reveal the function of AC under normal conditions, in this study, we combined electrophysiological recording and psychophysical experiments on the same animal to investigate whether AC is involved in a simple auditory task. We recorded the neural activities of the primary auditory cortex (A1) using implanted electrodes, while freely-moving cats performed a tone-detection task in which they were required to lick a metal tube to obtain a food reward after hearing a tone pip. The performance of the cats’ behavioral response increased with the increase of tone intensity, and the neural activities of A1 covaried with the behavioral performance. Also, whether the tone-detection behavior was interfered by a wideband noise was dependent on whether the tone-evoked neural response was masked by the noise-evoked response. Our results did not support that A1 neurons directly associate with the cat''s behavioral decision; instead, they may mainly generate a neural representation of stimulus amplitude for further processing to determine whether a tone occurred or not. [Copyright &y& Elsevier]

To characterize their soundscape perception, preschool children were subjected to inclusive soundscape exposure conditions (both indoor and outdoor) and were asked to evaluate the soundscape in this study comprising two experiments. In Experiment 1, reliable soundscape perception dimensions for preschool children were formulated using semantic differential analysis. In Experiment 2, the relationship between the dimensions and the overall soundscape evaluation and acoustic characteristics was investigated. The principal component analysis resulted in three factors (eigenvalue> 1), namely pleasantness , peacefulness , and regularity , explaining 69.96% of the variance (48.70%, 13.13%, and 8.13%, respectively). Among them, pleasantness and peacefulness significantly contributed to the overall soundscape evaluation (preference), as the improvement attitude of these two factors led to a higher chance of a positive attitude towards the overall soundscape preference (i.e., "like"). L A50 and L A10 contributed significantly to the regression for pleasantness and peacefulness , accounting for 41.2% and 92.6% of the prediction variance, respectively. Regularity had no significant effect on the overall soundscape evaluation. In addition, no acoustic characteristics significantly predicted this factor. The outcome showed that preschool children are capable of multi-scale evaluation of diverse soundscapes, embodying their awareness of both the quality and influence of the acoustic environment. Their soundscape perception dimensions pertain to the features of the preschool period and are thus inconsistent with previous adults' soundscape dimensions. In addition, preschool children seem to desire mild and peaceful soundscapes under control. • Preschool children reported their perception of both indoor and outdoor soundscapes. • Preschoolers' soundscape perception dimensions: Pleasantness, Peacefulness, and Regularity. • Pleasantness and Peacefulness influenced the overall soundscape evaluation. • L A50 significantly contributed to the regression for Pleasantness. • L A10 significantly contributed to the regression for Peacefulness. [ABSTRACT FROM AUTHOR]

The trade-off between noise and temperature and their combined effects on discomfort were studied on 108 lightly clothed subjects (0.6 clo), individually exposed for 2 h in a climatic chamber. Every 10 min of the first hour, subjects could modify the experimental conditions by deciding a change in temperature or noise. However, any change in one parameter was experimentally associated with a fixed change in the other parameter according to eight predetermined designs and all trials for thermal improvement were detrimental to acoustic comfort and conversely. Four initial exposures started at thermoneutrality (24 °C) in a noisy environment (85 dBA, recorded fan noise), the reduction of noise being linked to a temperature change towards cool or warm climates. The other four conditions started at a low noise level (35 dBA) but in a cool (14 or 19 °C) or warm (29 or 34 °C) environment, the reduction of thermal discomfort towards 24 °C leading to a louder noise. After six possible voluntary changes, the environment was kept constant for 1 h. Ambient parameters, skin temperatures, and subjective estimates were recorded.Results showed that females accepted noisier environments than males, suggesting that thermal comfort is dominant for women. Noise was rated as the most unpleasant factor when initial conditions were noisy whereas temperature was the most disturbing factor when subjects began the experiment with thermal conditions far from thermoneutrality. Finally, although the combined effects of noise and temperature did not influence the physiological data, our results suggest that noise may alter thermal pleasantness in warm conditions. [Copyright &y& Elsevier]

Models of perceived affective quality of soundscapes have been recently included into standards to guide the measurement and improvement of urban soundscapes. Such models have been developed in outdoor contexts and their validity in indoor built environments is unclear. A laboratory listening test was performed in a mock-up living room with a window sight, in order to develop an indoor soundscape model for residential buildings. During the test, 35 participants were asked to rate 20 different scenarios each. Scenarios were defined by combining four indoor sound sources and five urban environments, filtered through a window ajar, on 97 attribute scales. By applying principal component analysis, Comfort , Content, and Familiarity , were extracted as the main perceptual dimensions explaining respectively 58%, 25% and 7% of the total variance. Relationships between the principal component scores, acoustic parameters and indoor and outdoor sound categories were investigated. Comfort , Content, and Familiarity were found to be better predicted respectively by loudness N 10 , level variability L A10 -L A90 and sharpness S. The magnitude of linear-mixed-effect model predictions sensibly improved by accounting for sound categories, thus pointing at the importance of semantic meaning of sounds in indoor soundscape assessment. A measurement system is proposed, based on a 2-D space defined by two orthogonal axes, Comfort and Content , and two additional axes, Engagement and Privacy – Control , rotated 45° on the same plane. The model indicates the perceptual constructs to be measured (e.g. in post-occupancy evaluations), the attribute scales to be employed and actions to improve indoor soundscape quality, thus providing a reference for both research and practice. • Laboratory listening tests reproduced indoor soundscapes in living rooms. • Comfort , Content and Familiarity are the main dimensions of acoustic perception. • Privacy-Control and Engagement are at a 45° rotation from Comfort and Content. • Sound categories are fundamental predictors of indoor soundscape quality. [ABSTRACT FROM AUTHOR]