Long-time trends in ship traffic noise for four sites off the North American West Coast

Measurements (1994-2007) from four cabled-to-shore hydrophone systems located off the North American west coast permit extensive comparisons between "contemporary" low frequency ship traffic noise (25-50 Hz) collected in the past decade to measurements made over 1963-1965 with the same in-water equipment at the same sites. An increase of roughly 10 dB over the band 25-40 Hz at one site has already been reported [Andrew et al., Acoust. Res. Lett. Online 3(2), 65-70 (2002)]. Newly corrected data from the remaining three systems generally corroborate this increase. Simple linear trend lines of the contemporary traffic noise (duration 6 to 12+ years) show that recent levels are slightly increasing, holding steady, or decreasing. These results confirm the prediction by Ross that the rate of increase in traffic noise would be far less at the end of the 20th century compared to that observed in the 1950s and 1960s.     

Further analysis of traffic noise in a high-rise city

This Note presents the findings of a further analysis of the results of road traffic noise measurements made in a high-rise city. The means and standard deviations of the sound pressure levels within the industrial, commercial, commercial/residential and residential areas are only very marginally different from one another.     

Monitoring of anthropogenic acoustic noise in the shelf of Sakhalin Island

The method and results of many days of measurements of acoustic noise generated during installation of the oil and gas producing platform PA-B and construction of an underwater pipeline in the north-eastern shelf of Sakhalin Island are described. Acoustic measurements were carried out simultaneously with the use of five autonomous radio-hydroacoustic stations installed along the coast in a 43 km long line. The measurement objective was to control the level of anthropogenic sounds in a real time scale at the boundary of the coastal feeding area of a unique population of gray whales.     

Target enhancement and noise cancellation in the identification of a rudimentary sound source in noise

Perturbation analysis was used to determine the relative contribution of target enhancement and noise cancellation in the identification of rudimentary sound source in noise. In a two-interval, forced-choice procedure, listeners identified the impact sound produced by the larger of two stretched membranes as target. The noise on each presentation was the impact sound of a variable-sized plate. For four of five listeners, the relative weights on the noise were positive indicating enhancement, and for the remaining listeners, they were negative indicating cancellation. The results underscore the difficulty with evaluating models of masking solely in terms of measures of performance accuracy.     

The effects of site selected variables on human responses to traffic noise,part I: Type of housing by traffic noise level

The results of the first part of a field study of human response to traffice noise are reported, along with the general methodology of the entire study. The research was carried out by carefully selecting subjects at sites that had the desired values of selected site variables. Human response measurements were obtained from interviewer administered structured questionnaires, and were as spatially and temporally coincident as possible with the noise measurements. Noise measurements were obtained from six days of rapidly sampled recordings. In this first part the effects of traffic noise level and housing type were considered. Although traffic noise level was the major correlate of the intensity of negative responses to traffic noise, traffic noise level by housing type interaction effects were also observed and were attributed to the accuracy of perceiving the vehicle flow rate and day-night noise level differences. Spontaneous responses supported the validity of the elicited responses.     

Investigation of the dose-response relationship for road traffic noise in Assiut, Egypt

A field study has been carried out in urban Assiut city, Egypt. The goals of this study are: (1) to carry out measurements to evaluate road traffic noise levels, (2) to determine if these levels exceeds permissible levels, (3) to examine people’s attitudes towards road traffic noise, (4) to ascertain the relationship between road traffic noise levels and degree of annoyance. The measurements indicate that traffic noise noise levels are higher than those set by Egyptian noise standards and policy to protect public health and welfare in residential areas: equivalent continuous A - weighted sound pressure levels (L_A eq) = 80 dB and higher were recorded, while maximum permissible level is 65 dB. There is a strong relationship between road traffic noise levels and percentage of highly annoyed respondents. Higher road traffic noise levels mean that the percentage of respondents who feel highly annoyed is also increased.     

The effects of site selected variables on human responses to traffic noise,part III: Community size by socio-economic status by traffic noise level

This paper reports the results of the third part of a field study of human responses to traffic noise. The influence of traffic noise level, community size, and socio-economic status were investigated in a controlled manner determined by subject selection procedures. Human responses were obtained from interviewer administered questionnaires, and were as spatially and temporally coincident with the noise measurements as possible. Noise measurements were obtained from several days of rapidly sampled digital recordings. Traffic noise level was the major predictor of the intensity of elicited responses. A number of other significant effects were observed largely related to community size. These were explained as due to parallel variations in the perceived necessity of vehicles, the annoyance with aircraft noise, and the logarithm of the vehicle flow rate. The results did demonstrate effects related to community size, and thus it is unwise to extrapolate the results of large city noise studies to small communities and rural areas.     

The effects of site selected variables on human responses to traffic noise,Part II: Road type by socio-economic status by traffic noise level

The results of the second part of a field study of human response to traffic noise are reported. The influence of traffic noise level, socio-economic status, and road type (freeway or conventional road) were investigated in a controlled manner determined by subject selection procedures. Human response measures were obtained from interviewer administered questionnaires, and were as spatially and temporally coincident with the noise measurements as possible. Noise measurements were obtained from six days of rapidly sampled digital recordings. Although traffic noise level was the major predictor of the intensity of negative responses, other site variables produced significant effects. Parallel variations in the day-night difference in sound levels appeared to contribute to these effects. Spontaneous responses supported the validity of the elicited responses. Freeway noise was found to produce a more continuously disturbing noise environment and was concluded to be a more pervasive form of disturbing environmental noise.     

Two-parametric model of the spectrum of traffic noise in Tomsk

The technique of mapping urban noise is proposed on the basis of a two-parameter model of the acoustic noise spectrum. The acoustic noise and spatial distribution of the decay rate in Tomsk are mapped. The factors influencing the formation of the acoustic noise of traffic flow are described. Analysis is performed on how different operating modes of a vehicle??s internal combustion engine affect the background level of acoustic noise.     

Measurements and analysis of the traffic noise in amman,jordan and its effects

This paper gives the measured values of the sound pressure level (L₁₀) resulting from traffic noise measurements over periods of 1 h and 18 h. These measurements were done daily over long and difficult periods, and at different periods and at different locations, in the greater Amman (Jordan) area. Measured values are presented versus the numbers of vehicles accounted for at the time of measurement. Comparisons between calculated and measured levels for both Amman and other cities are given. Annoyance, from the traffic noise, to the people living around the measurement sites is given in a percentage form.     

Saturated absorption linewidth: Influence of the source frequency noise

The effect of the source FM noise on the lineshape in sub-Doppler saturation spectroscopy is examined both theoretically and experimentally. We show that the line profile is simply given by the convolution of the homogeneous profile with an effective spectrum, depending on the relative values of the sample relaxation time and of the source frequency correlation time but not departing significantly from the source field power spectrum in the usual cases. This result is well supported by a millimeter wave experiment involving a nearly perfect source, frequency modulated by a Gaussian noise.     

Aircraft noise: accounting for changes in air traffic with time of day

Aircraft noise contours are estimated using model calculations and, due to their impact on land use planning, they need to be highly accurate. During night time, not only the number and dominant types of aircraft may differ from daytime but also the flight paths flown may differ. To determine to which detail these variations in flight paths need to be considered, calculations were performed exemplarily for two airports using all available radar data over 1 year, taking into account their changes over the day. The results of this approach were compared with results of a simpler approach which does not consider such changes. While both calculations yielded similar results for the day and close to the airport, differences increased with distance as well as with the period of day (day相似文献   

Perceptual interaction of the harmonic source and noise in voice

Although the amount of inharmonic energy (noise) present in a human voice is an important determinant of vocal quality, little is known about the perceptual interaction between harmonic and inharmonic aspects of the voice source. This paper reports three experiments investigating this issue. Results indicate that perception of the harmonic slope and of noise levels are both influenced by complex interactions between the spectral shape and relative levels of harmonic and noise energy in the voice source. Just-noticeable differences (JNDs) for the noise-to-harmonics ratio (NHR) varied significantly with the NHR and harmonic spectral slope, but NHR had no effect on JNDs for NHR when harmonic slopes were steepest, and harmonic slope had no effect when NHRs were highest. Perception of changes in the harmonic source slope depended on NHR and on the harmonic source slope: JNDs increased when spectra rolled off steeply, with this effect in turn depending on NHR. Finally, all effects were modulated by the shape of the noise spectrum. It thus appears that, beyond masking, understanding perception of individual parameters requires knowledge of the acoustic context in which they function, consistent with the view that voices are integral patterns that resist decomposition.     

Characteristics of road traffic noise in Hanoi and Ho Chi Minh City, Vietnam

Noise pollution due to road traffic is a major global concern because of its negative impact on the quality of life in communities everywhere. In Vietnam, traffic noise has become an increasingly noticeable and serious problem in large cities like Hanoi and Ho Chi Minh City. To gain more insight into the characteristics of this noise, intensive noise measurements were conducted in Hanoi and Ho Chi Minh City in September 2005 and September 2007, respectively. A comprehensive dataset of noise was obtained that included 24-h noise measurements as well as short-term noise recordings. The volume of traffic was also quantified by reproducing video camera recordings. Noise datasets from both cities were then compared with a dataset of Japanese traffic noise obtained in Kumamoto. The results showed that the traffic noise in Hanoi and Ho Chi Minh City was characterized by relatively high noise exposure levels due to the large number of motorbikes and frequent horn sounds. The sound of horns contributed a definite impact of 0-4 dB on noise exposure in Hanoi and Ho Chi Minh City, where noise levels decreased with the absence of horn sounds. Our results also showed differences in the characteristic traffic noise of Vietnam and Japan.