Speech Interference Research Articles

Open plan offices as sociotechnical systems: What matters and to whom?

Open plan offices have proliferated for the past several decades with more and more workers being concentrated in office buildings. Several studies have identified a number of negative factors associated with open plan offices, and those include noise, speech interference, lack of privacy, and a perceived loss of control over work. While negative factors have been identified several times in the literature, many studies rely on either surveys or highly controlled environments. The objective of this study was to use a quasi-naturalistic environment based on a scaled world model to test three hypotheses of the impacts of office interference on editing and web navigation performance and mental workload. A mixed factor design was used that utilized continuous speech recordings, discontinuous speech recordings, and a quiet condition. Individual differences questionnaires were administered to measure focused attention, stress, and cognitive failures. After task completion, participants recorded mental workload ratings. Participants had higher performance accuracy in the document editing task across the speech interference conditions. Mental workload ratings were higher in the web navigation task in the discontinuous speech condition compared to the continuous speech condition. In contrast to the hypothesis, those reporting stronger focused attention performed more poorly across all speech conditions. Overall, the results were mixed. OPO work design must focus on individual differences among workers to determine how to customize design to facilitate performance.

Design of multi-chamber cylindrical silencers with microperforated elements

The objective in this study was to develop a compact, multi-chamber silencer incorporating dissipative microperforated elements that could be used to reduce transmitted noise in a flow system. Two expansion mufflers in series were used to create a relatively compact system that attenuated sound effectively over the speech interference range. The microperforated elements were used both to improve the acoustic performance of the silencer and to reduce the system pressure drop with respect to a muffler without a microperforated lining. Both finite element modeling (FEM) simulation and experimental methods were employed in the detailed design of the multi-chamber silencer. In the FEM simulations, the microperforated lining was modeled as a fluid layer having complex properties, and the model was used, for example, to identify the optimal location of the microperforated lining. The predicted results were successfully compared with full-scale experimental results that were obtained by using a four-microphone standing wave tube.

The multiple contributions of interaural differences to improved speech intelligibility in multitalker scenarios.

Spatial separation of talkers is known to improve speech intelligibility in a multitalker scenario. A contribution of binaural unmasking, in addition to a better-ear effect, is usually considered to account for this advantage. Binaural unmasking is assumed to result from the spectro-temporally simultaneous presence of target and masker energy with different interaural properties. However, in the case of speech targets and speech interference, the spectro-temporal signal-to-noise ratio (SNR) fluctuates strongly, resulting in audible and localizable glimpses of target speech even at adverse global SNRs. The disparate interaural properties of target and masker may thus lead to improved segregation without requiring simultaneity. This study addresses the binaural contribution to spatial release from masking due to simultaneous disparities in interaural cues between target and interferers. For that purpose stimuli were designed that lacked simultaneously occurring disparities, but yielded a percept of spatially separated speech nearly indistinguishable from that of non-modified stimuli. A phoneme recognition experiment with either three collocated or spatially separated talkers showed a substantial spatial release from masking for the modified stimuli. The results suggest that binaural unmasking made a minor contribution to spatial release from masking, and that rather the interaural cues mediated by dominant speech components were essential.

Rehabilitation of patients after ear surgery: prospects of auditory and vestibular training in non­invasive neuromodulation

The objective of the research is to evaluate the efficacy of rehabilitation in 73 patients with hearing and vestibulation impairment after ear surgery. Rehabilitation had the form of a set of auditory and vestibular training in conditions of non­invasive neuromodulation. Vestibular training had the form of an exercise on equilibrium control with the eyes closed performed with the help of Brain Port device during a week after surgery. Audial training was a 10-days acoustic stimulation on the expiry of 1 month after surgery. In both cases non­invasive neuromodulation was provided by electrotactile stimulation of tongue using Brain Port device. The data of tone threshold audiometry, speech intelligibility in conditions of speech interference, computerized posturography and gate examination were evaluated. The results confirm effectiveness of the used rehabilitation activities for speech intelligibility and gait improvement in majority of the patients.

Study of physio-psychological effects on traffic wardens due to traffic noise pollution; exposure-effect relation.

BackgroundNoise pollution has increased to alarming extent in most of the urban areas in Pakistan. It is assumed even more perilous than air and water pollution due to its direct acute and chronic physio-psychological effects. The objective of this study is to analyze and evaluate the psychological and physiological effects caused by traffic noise on traffic wardens and to find relation type between exposure time and effect.MethodsThree wardens check posts near roads were selected for survey in Taxila and Islamabad cities of Pakistan. Survey conducted included noise measurements at aforementioned check posts for one month and Performa based interviews of traffic wardens.Results and conclusionsAnalysis of results showed that noise levels varied between 85-106 dB hence violating OSHA regulations. Major psychological effects found in wardens were aggravated depression 58%, stress 65%, public conflict 71%, irritation and annoyance 54%, behavioral affects 59% and speech interference 56%. Physiological effects found were hypertension 87%, muscle tension 64%, exhaustion 48%, low performance levels 55%, concentration loss 93%, hearing impairment 69%, headache 74% and cardiovascular issue 71%. Relation between exposure time and effects were evaluated by using simple regression test in excel. Percentage of psychological and physiological effects in wardens varied with the exposure time; aggravated depression (R2 = 0.946, P = 0.133), stress suffering (R2 = 0.014, P = 0.173), public conflict (R2 = 0.946, P = 0.133), irritation and annoyance (R2 = 0.371, P = 0.137), behavioral affects (R2 = 0.596, P = 0.0616) and speech interference (R2 = 0.355, P = 0.445), hypertension (R2 = 0.96, P = 0.00095) and cardiovascular issue (R2 = 0.775, P = 0.044).

Evaluation of the Extent and Potential Impacts of Noise Pollution inside Public Service Vehicles (PSVs) in Nairobi City, Kenya

Public service vehicles (PSVs) in Nairobi City, Kenya, have a tendency of playing loud music inside the vehicles resulting in disturbing noise. The objective of this study was to evaluate the extent of noise pollution inside PSVs in Nairobi City and predict possible impacts of the noise on PSV users. A sample of 60 randomly selected PSVs were analyzed. Posing as passengers inside the vehicles, noise measurements were taken using a digital integrating sound level meter (SVANTEK 971) inside these matatus. The measured noise levels were compared with corresponding legislated limits and the deviation thereof used to quantify the extent of pollution and probe the effectiveness of existing noise laws. Additionally, potential effects of the noise were predicted by comparing measured noise levels with respective guidelines recommended to protect public health and welfare from various adverse impacts of noise. The study results showed that PSV users in Nairobi are exposed to 86.3±9.6 dB A of noise inside PSVs and all the sampled vehicles did not comply with Kenyan noise regulations. PSVs plying northern Nairobi area were found to be the noisiest at 92.2±9.4 dBA, followed by Nairobi West PSVs at 88.7±9.6 dBA; Nairobi South PSVs at 83.1±6.3 dBA and Nairobi East PSVs at 81.2±7.7 dBA. The growing habit of PSVs playing extremely loud music/radio using sound amplifying equipment, was found to be a major contributor to noise pollution inside the vehicles, in addition to normal vehicular traffic sounds. The high noise levels put city dwellers at risk of such adverse effects of noise as noise-induced hearing loss (NIHL); physiological and psychological noise effects; speech interference, sleep disturbance; annoyance, social and behavioral effects. This calls not only for intensified noise law enforcement in the city, but also puts to question the effectiveness of existing noise laws to control noise in the city.

主観的評価に基づくオープンプランオフィスにおける執務作業時のサウンドマスキングの適用に関する検討

The purpose of this study was to examine masking systems between desks in open plan offices installed with an appropriate sound masking system. Word intelligibility tests for unwanted speech interference from nearby workstations, and subjective judgements on the degree of discomfort of masking sound were conducted in a simulated office workplace. The results were as follows: (1) The level of masker sound could be decreased to 5-10 dB when focused on desk work relative to the masking level in non-desk work; (2) We showed that the optimum masking level in a desk work environment is a target/masker ratio of -2 dB.

A complementary metric to define a buffer zone in brazilian airports

The legislation on aircraft noise in Brazil recognizes the DNL metric as the only tool to perform noise airport zoning. This paper examines the importance of adopting an auxiliary metric to characterize the impacts of aircraft noise at a specific building sensitive to noise, especially in analysis of speech interference and sleep disturbance. A complementary measure, LAeq, associated with the Brazilian standard for controlling noise pollution, NBR 10151 (Assessment of noise in inhabited areas, for Community comfort), was used in this work. A control curve based the LAeq and on the standart was created and the buffer area between the control curve and DNL 65dB (A) was the object of study of this work. The results showed a high number of people who are affected by aircraft noise and are despised by the public authorities, only at Congonhas airport this number reaches the mark of 596,808 people. The adoption of complementary metric is intended to assist decision makers in identifying people highly annoyed by aircraft noise, allowing the creation of mitigation measures in the affected areas.

Optimal design of multi-layer microperforated sound absorbers

Microperforated polymer films can offer and effective solution when it is desired to design fiber-free sound absorption systems. The acoustic performance of the film is determined by hole size and shape, by the surface porosity, by the mass per unit area of the film, and by the depth of the backing air layer. Single sheets can provide good absorption over a one of two octave range, but if absorption over a broader range is desired, it is necessary to use multilayer treatments. Here the design of a multilayer sound absorption system is described, where the film is considered to have a finite mass per unit area and also to have conical perforations. It will be shown that it is possible to design compact absorbers that yield good performance over the whole speech interference range. In the course of the optimization it has been found that there is a tradeoff between cone angle and surface porosity. The design of lightweight, multilayer functional absorbers will also be described, and it will be shown, for example, that it is possible to design systems that simultaneously possess good sound absorption and barrier characteristics.

Prosodic interference in speech of bilingual studentswhile learning English

Prosodic interference in speech of bilingual studentswhile learning English

Landline versus Cell Phone Surveys – Interviewers' Experience

The aim of this paper is to outline the results of the study that was carried out among CATI (Computer Assisted Telephone Interview) interviewers from October 2009 to August 2010. 12 major Polish research organizations as well as two companies in Norway and Iceland participated in the research. The research was based on a standardized self-completion questionnaire (in total 942 interviewers were surveyed) and in-depth interviews (IDI) which were conducted with 49 experienced CATI interviewers. This paper focuses on specific results of the qualitative part of the project; it investigates difficult situations encountered by the interviewers while conducting telephone surveys. During in-depth interviews, the interviewers were encouraged to describe the differences between “mobile” and “landline” respondents, especially in terms of the persuasiveness of the introductory speech and communication interferences during question-asking and answer-recording stage. The interviewers were also asked to elaborate on the relationship between the probability of encountering difficulties while talking to the respondents on the mobile / landline phone and different features, such as the B2B/B2C (« business to business »/« business to consumers ») character of the project, socio-demographic characteristics of the respondent, sampling procedures (RDD versus list-assisted samples), etc.

Abnormal Binaural Spectral Integration in Cochlear Implant Users

Bimodal stimulation, or stimulation of a cochlear implant (CI) together with a contralateral hearing aid (HA), can improve speech perception in noise However, this benefit is variable, and some individuals even experience interference with bimodal stimulation. One contributing factor to this variability may be differences in binaural spectral integration (BSI) due to abnormal auditory experience. CI programming introduces interaural pitch mismatches, in which the frequencies allocated to the electrodes (and contralateral HA) differ from the electrically stimulated cochlear frequencies. Previous studies have shown that some, but not all, CI users adapt pitch perception to reduce this mismatch. The purpose of this study was to determine whether broadened BSI may also reduce the perception of mismatch. Interaural pitch mismatches and dichotic pitch fusion ranges were measured in 21 bimodal CI users. Seventeen subjects with wide fusion ranges also conducted a task to pitch match various fused electrode-tone pairs. All subjects showed abnormally wide dichotic fusion frequency ranges of 1-4 octaves. The fusion range size was weakly correlated with the interaural pitch mismatch, suggesting a link between broad binaural pitch fusion and large interaural pitch mismatch. Dichotic pitch averaging was also observed, in which a new binaural pitch resulted from the fusion of the original monaural pitches, even when the pitches differed by as much as 3-4 octaves. These findings suggest that abnormal BSI, indicated by broadened fusion ranges and spectral averaging between ears, may account for speech perception interference and nonoptimal integration observed with bimodal compared with monaural hearing device use.

Simulating the effect of acoustic treatment types for residential balconies with road traffic noise

Development of design guides to estimate the difference in speech interference level due to road traffic noise between a reference position and balcony position or façade position is explored. A previously established and validated theoretical model incorporating direct, specular and diffuse reflection paths is used to create a database of results across a large number of scenarios. Nine balcony types with variable acoustic treatments are assessed to provide acoustic design guidance on optimised selection of balcony acoustic treatments based on location and street type. In total, the results database contains 9720 scenarios on which multivariate linear regression is conducted in order to derive an appropriate design guide equation. The best fit regression derived is a multivariable linear equation including modified exponential equations on each of nine deciding variables, (1) diffraction path difference, (2) ratio of total specular energy to direct energy, (3) distance loss between reference position and receiver position, (4) distance from source to balcony façade, (5) height of balcony floor above street, (6) balcony depth, (7) height of opposite buildings, (8) diffusion coefficient of buildings and (9) balcony average absorption. Overall, the regression correlation coefficient, R2, is 0.89 with 95% confidence standard error of ±3.4dB.

Noise level and annoyance of Industrial factories in Duhok city

Noise pollution is considered as more important environmental problem, especially in the industrialized and developed countries. Industrial noise is an important source of noise pollution, which annoys and disrupts the daily activities of workers. This study focuses on the industrial noise and its effects on workers. Thirteen different industries chosen randomly in Duhok city, in Kurdistan region, North of Iraq. To cover this study an instrument for measurement the sound level was used, in addition to a questionnaire contains (38) questions to study all the possible reported effects of noise on humans, (90) workers of different industries were chosen, the questionnaires were analysis to determine how much employees were affected by high noise levels in the workplace. During the survey, it has been specified that all industries noise levels measurement are much above the maximum (OSHA) exposure limits. 81.11% of workers are annoyed from the noise in their workplaces. To determine whether the effects of noise were statistically significant or not, a Chi-Square test was used. At a level of significance, p≤0.05, a relationship between duration of employment years and feeling annoyed are statistically significant. It was found that the physiological and psychological effects of noise i.e. headache, disturbs their peace of mind, nervousness, stressful, speech interference and insomnia are statistically significant. However, dizziness is statistically not significant. 65.56% of respondents in these industries are suffering from hearing problems, 34.44% of them have complaints about ringing in ears and only 10% of workers were used EPE.

건설공사장 소음의 위해성 평가

In the present study, annoyance caused by diverse construction noises was evaluated through surveys. A survey with a total of 110 construction workers was carried out to investigate annoyance from construction noises at different construction phases. The most effective item of adverse by con- struction noise was annoyance and the most annoyed construction stage was destruction construction. There were high correlation between work performance and work safety as well as work safety and speech interference. Participant's noise sensitivity were significant between low and high group at work performance, work safety, speech interference.

Far-field acoustic modeling of rocket noise to determine community impacts

The emerging commercial space market is generating interest in commercial launch site (“spaceport”) development around the United States. FAA regulations require all new spaceports to acquire a launch site operator’s license, which is considered a Federal action subject to environmental review. Potential noise impacts are evaluated based on FAA Order 1050.1E, Change 1, Environmental Impacts: Policies and procedures, which include the assessment of DNL and may be supplemented with additional acoustical metrics. These supplemental metrics may range from speech interference to structural damage impacts. Extensive studies and research have examined the appropriateness of these metrics in relation to aircraft operations. However, the differences between these acoustic sources and operational modes stress the need for computer models and impact criteria specific to launch vehicles. Further measurements and research are needed to improve rocket source characterization, long-range sound propagation of high amplitude waveforms through complex atmosphere, and environmental and community impacts. The evolving nature of the regulatory environment surrounding rocket noise warrants a renewed focus on appropriate noise modeling and impact criteria to determine potential conflicts with launch noise.

The role of high-frequency envelope fluctuations for speech masking release

The speech-based envelope power spectrum model (sEPSM; Jo/rgensen and Dau, 2011; Jo/rgensen et al., 2013) was shown to successfully predict speech intelligibility in conditions with stationary and fluctuating interferers, reverberation, and spectral subtraction. The key element in the model was the multi-resolution estimation of the signal-to-noise ratio in the envelope domain (SNRenv) at the output of a modulation filterbank. The simulations suggested that mainly modulation filters centered in the range from 1-8 Hz contribute to speech intelligibility in the case of stationary maskers whereas modulation filters tuned to frequencies above 16 Hz might be important in the case of fluctuating maskers. In the present study, the role of high-frequency envelope fluctuations for speech masking release was further investigated in conditions of speech-on-speech Simulations were compared to various measured data from normal-hearing listeners (Festen and Plomp, 1990; Christiansen et al., 2013). The results support the hypothesis that high-frequency envelope fluctuations (>30 Hz) are essential for speech intelligibility in conditions with speech interferers. While the sEPSM reflects effects of energetic and modulation masking in speech intelligibility, the remaining unexplored effect in some conditions may be attributed to, and defined as, informational masking.

The role of across-frequency envelope processing for speech intelligibility

Speech intelligibility models consist of a preprocessing part that transforms the stimuli into some internal (auditory) representation, and a decision metric that quantifies effects of transmission channel, speech interferers, and auditory processing on the speech intelligibility. Here, two recent speech intelligibility models, the spectro-temporal modulation index [STMI; Elhilali et al. (2003)] and the speech-based envelope power spectrum model [sEPSM; Jo/rgensen and Dau (2011)] were evaluated in conditions of noisy speech subjected to reverberation, and to nonlinear distortions through either a phase jitter process or noise reduction via spectral subtraction. The contributions of the individual preprocessing stages in the models and the role of the decision metrics were analyzed in the different experimental conditions. It is demonstrated that an explicit across-frequency envelope processing stage, as assumed in the STMI, together with the metric based on the envelope power signal-to-noise ratio, as assumed in the sEPSM, are required to account for all three conditions. However, a simple weighting of the across-frequency variance of the modulation power at the output of the (purely temporal) modulation filterbank is assumed to be sufficient to describe the data, i.e., a joint two-dimensional modulation filterbank might not be required.

Acoustic quality on board ships

Approaches to determine acoustic quality on board ships are usually based on a three- or five-stage classification system using critical A-weighted sound pressure levels. At times other criteria such as the sound insulation between cabins, impact noise from upper decks, speech interference levels or general noise-rating curves are also taken into account. With regard to increasing requirements of passenger comfort and crew accommodation, a more detailed evaluation of auditory perception on board would be worthwhile. Furthermore, other industrial sectors have stated that psychoacoustic or room acoustic models are useful tools to analyze and guarantee product-sound quality. In order to find better indicators for the quantification of acoustic performance of (luxury) vessels, audio material was acquired at a sea trial and evaluated with the help of a paired-comparison listening test in the laboratory by 30 test-persons. Also, the possibility to comment the judgments was given to the subjects. The results were then analyzed by using the statistic model of the “Law of Comparative Judgment” and compared by correlation analysis with physical, psychoacoustic, and room acoustic parameters. Highly correlating parameters could be identified.

Speech interference and transmission on residential balconies with road traffic noise

Balcony acoustic treatments can mitigate the effects of community road traffic noise. To further investigate, a theoretical study into the effects of balcony acoustic treatment combinations on speech interference and transmission is conducted for various street geometries. Nine different balcony types are investigated using a combined specular and diffuse reflection computer model. Diffusion in the model is calculated using the radiosity technique. The balcony types include a standard balcony with or without a ceiling and with various combinations of parapet, ceiling absorption and ceiling shield. A total of 70 balcony and street geometrical configurations are analyzed with each balcony type, resulting in 630 scenarios. In each scenario the reverberation time, speech interference level (SIL) and speech transmission index (STI) are calculated. These indicators are compared to determine trends based on the effects of propagation path, inclusion of opposite buildings and difference with a reference position outside the balcony. The results demonstrate trends in SIL and STI with different balcony types. It is found that an acoustically treated balcony reduces speech interference. A parapet provides the largest improvement, followed by absorption on the ceiling. The largest reductions in speech interference arise when a combination of balcony acoustic treatments are applied.