Showing papers on "Noise published in 2017"

Hidden Hearing Loss? No Effect of Common Recreational Noise Exposure on Cochlear Nerve Response Amplitude in Humans.

Abstract: This study tested hypothesized relationships between noise exposure and auditory deficits. Retrospective assessment of potential associations between noise exposure history and performance on an audiologic test battery and prospective assessment of potential changes in performance after new recreational noise exposure were completed. METHODS: 32 participants (13M, 19F) with normal hearing (25-dB HL or better,0.25-8 kHz) were asked to participate in 3 pre- and post-exposure sessions including: otoscopy, tympanometry, distortion product otoacoustic emissions (DPOAEs) (f2 frequencies 1-8 kHz), pure-tone audiometry (0.25-8 kHz), Words-in-Noise (WIN) test, and electrocochleography (eCochG) measurements at 70, 80, and 90-dB nHL (click, and 1-4 kHz tone-bursts). The first session was used to collect baseline data, the second session was collected the day after a loud recreational event, and the third session was collected 1-week later. Of the 32 participants, 26 completed all 3 sessions. RESULTS: The retrospective analysis did not reveal statistically significant relationships between noise exposure history and any auditory deficits. The day after new exposure, there was a statistically significant correlation between noise “dose” and WIN performance overall, and within the 4-dB signal-to-babble ratio. In contrast, there were no statistically significant correlations between noise dose and changes in threshold, DPOAE amplitude, or AP amplitude the day after new noise exposure. Additional analyses revealed a statistically significant relationship between TTS and DPOAE amplitude at 6 kHz, with temporarily decreased DPOAE amplitude observed with increasing TTS. CONCLUSIONS: There was no evidence of auditory deficits as a function of previous noise exposure history, and no permanent change in audiometric, electrophysiologic, or functional measures after new recreational noise exposure. There were very few participants with TTS the day after exposure - a test time selected to be consistent with previous animal studies. The largest observed TTS was approximately 20-dB. The observed pattern of small TTS suggests little risk of synaptopathy from common, recreational noise exposure, and that we should not expect to observe changes in evoked potentials for this reason. No such changes were observed in this study. These data do not support suggestions that common, recreational noise exposure is likely to result in “hidden hearing loss”.

Characteristics of Real-World Signal to Noise Ratios and Speech Listening Situations of Older Adults With Mild to Moderate Hearing Loss.

Abstract: Objectives The first objective was to determine the relationship between speech level, noise level, and signal to noise ratio (SNR), as well as the distribution of SNR, in real-world situations wherein older adults with hearing loss are listening to speech. The second objective was to develop a set of prototype listening situations (PLSs) that describe the speech level, noise level, SNR, availability of visual cues, and locations of speech and noise sources of typical speech listening situations experienced by these individuals. Design Twenty older adults with mild to moderate hearing loss carried digital recorders for 5 to 6 weeks to record sounds for 10 hours per day. They also repeatedly completed in situ surveys on smartphones several times per day to report the characteristics of their current environments, including the locations of the primary talker (if they were listening to speech) and noise source (if it was noisy) and the availability of visual cues. For surveys where speech listening was indicated, the corresponding audio recording was examined. Speech-plus-noise and noise-only segments were extracted, and the SNR was estimated using a power subtraction technique. SNRs and the associated survey data were subjected to cluster analysis to develop PLSs. Results The speech level, noise level, and SNR of 894 listening situations were analyzed to address the first objective. Results suggested that as noise levels increased from 40 to 74 dBA, speech levels systematically increased from 60 to 74 dBA, and SNR decreased from 20 to 0 dB. Most SNRs (62.9%) of the collected recordings were between 2 and 14 dB. Very noisy situations that had SNRs below 0 dB comprised 7.5% of the listening situations. To address the second objective, recordings and survey data from 718 observations were analyzed. Cluster analysis suggested that the participants' daily listening situations could be grouped into 12 clusters (i.e., 12 PLSs). The most frequently occurring PLSs were characterized as having the talker in front of the listener with visual cues available, either in quiet or in diffuse noise. The mean speech level of the PLSs that described quiet situations was 62.8 dBA, and the mean SNR of the PLSs that represented noisy environments was 7.4 dB (speech = 67.9 dBA). A subset of observations (n = 280), which was obtained by excluding the data collected from quiet environments, was further used to develop PLSs that represent noisier situations. From this subset, two PLSs were identified. These two PLSs had lower SNRs (mean = 4.2 dB), but the most frequent situations still involved speech from in front of the listener in diffuse noise with visual cues available. Conclusions The present study indicated that visual cues and diffuse noise were exceedingly common in real-world speech listening situations, while environments with negative SNRs were relatively rare. The characteristics of speech level, noise level, and SNR, together with the PLS information reported by the present study, can be useful for researchers aiming to design ecologically valid assessment procedures to estimate real-world speech communicative functions for older adults with hearing loss.

Noise in the Neonatal Intensive Care Unit: What Does the Evidence Tell Us?

Abstract: Background:In 2014, more than 10% of all births in the United States were preterm (born at <37-weeks' gestation). These high-risk infants will often spend weeks to months within the neonatal intensive care unit (NICU), where noise levels can easily reach 120 decibels adjusted (dBA) on a regular and

Leveraging the urban soundscape: Auditory perception for smart vehicles

Abstract: Urban environments are characterised by the presence of distinctive audio signals which alert the drivers to events that require prompt action. The detection and interpretation of these signals would be highly beneficial for smart vehicle systems, as it would provide them with complementary information to navigate safely in the environment. In this paper, we present a framework that spots the presence of acoustic events, such as horns and sirens, using a two-stage approach. We first model the urban soundscape and use anomaly detection to identify the presence of an anomalous sound, and later determine the nature of this sound. As the audio samples are affected by copious non-stationary and unstructured noise, which can degrade classification performance, we propose a noise-removal technique to obtain a clean representation of the data we can use for classification and waveform reconstruction. The method is based on the idea of analysing the spectrograms of the incoming signals as images and applying spectrogram segmentation to isolate and extract the alerting signals from the background noise. We evaluate our framework on four hours of urban sounds collected driving around urban Oxford on different kinds of road and in different traffic conditions. When compared to traditional feature representations, such as Mel-frequency cepstrum coefficients, our framework shows an improvement of up to 31% in the classification rate.

Mountain chickadees adjust songs, calls and chorus composition with increasing ambient and experimental anthropogenic noise

Abstract: Vocal plasticity may allow birds to reduce masking effects of noise pollution arising from urbanization. Mountain chickadees (Poecile gambeli) use both songs and calls during the dawn chorus, which vary in masking susceptibility. Thus, increasing song or call frequency, or switching between vocalization types are all potential mechanisms to reduce masking during fluctuating noise conditions. Further, prior experience with noise pollution may be a necessary precursor to allow birds to alter signals in response to sudden noisy conditions. To determine how mountain chickadee songs, calls, and chorus composition are affected by noise, we recorded 55 males across gradients of local ambient noise and habitat urbanization in three cities in British Columbia, Canada. Of these individuals, 31 were also exposed to 5-min experimental noise treatments. Habitat urbanization was quantified through a continuous index reflecting properties of urbanized areas. Only song frequency increased with local ambient noise, and this effect varied regionally. In response to experimental noise exposure, males increased the frequency of their calls (but not of their songs), and varied their use of songs vs. calls. Interestingly, this response was dependent on local ambient noise levels: males in noisy areas shifted to using relatively more songs, whereas males in quiet areas shifted to using relatively more calls. These findings may suggest that although mountain chickadees are capable of adjusting their vocalizations, choosing a response which can lead to masking release may require prior exposure to high levels of ambient noise.

Land Use Regression Modeling of Outdoor Noise Exposure in Informal Settlements in Western Cape, South Africa.

Abstract: In low- and middle-income countries, noise exposure and its negative health effects have been little explored. The present study aimed to assess the noise exposure situation in adults living in informal settings in the Western Cape Province, South Africa. We conducted continuous one-week outdoor noise measurements at 134 homes in four different areas. These data were used to develop a land use regression (LUR) model to predict A-weighted day-evening-night equivalent sound levels (Lden) from geographic information system (GIS) variables. Mean noise exposure during day (6:00-18:00) was 60.0 A-weighted decibels (dB(A)) (interquartile range 56.9-62.9 dB(A)), during night (22:00-6:00) 52.9 dB(A) (49.3-55.8 dB(A)) and average Lden was 63.0 dB(A) (60.1-66.5 dB(A)). Main predictors of the LUR model were related to road traffic and household density. Model performance was low (adjusted R2 = 0.130) suggesting that other influences than those represented in the geographic predictors are relevant for noise exposure. This is one of the few studies on the noise exposure situation in low- and middle-income countries. It demonstrates that noise exposure levels are high in these settings.

White noise enhances new-word learning in healthy adults.

Abstract: Research suggests that listening to white noise may improve some aspects of cognitive performance in individuals with lower attention. This study investigated the impact of white noise on new word learning in healthy young adults, and whether this effect was mediated by executive attention skills. Eighty participants completed a single training session to learn the names of twenty novel objects. The session comprised 5 learning phases, each followed by a recall test. A final recognition test was also administered. Half the participants listened to white noise during the learning phases, and half completed the learning in silence. The noise group demonstrated superior recall accuracy over time, which was not impacted by participant attentional capacity. Recognition accuracy was near ceiling for both groups. These findings suggest that white noise has the capacity to enhance lexical acquisition.

DNN-based Causal Voice Activity Detector

Abstract: Voice Activity Detectors (VAD) are important components in audio processing algorithms. In general, VADs are two way classifiers, flagging the audio frames where we have voice activity. Most of them are based on the signal energy and build statistical models of the noise background and the speech signal. In the process of derivation, we are limited to simplified statistical models and this limits the accuracy of the classification. Using more precise, but also more complex, statistical models makes the analytical derivation of the solution practically impossible. In this paper, we propose using deep neural network (DNN) to learn the relationship between the noisy speech features and the correct VAD decision. In most of the cases we need a causal algorithm, i.e. working in real time and using only current and past audio samples. This is why we use audio segments that consist only of current and previous audio frames, thus making possible real-time implementations. The proposed algorithm and DNN structure exceeds the classic, statistical model based VAD for both seen and unseen noises.

Sound source positioning system based on distributed microphone array

Abstract: The invention discloses a sound source positioning system based on a distributed microphone array, and the system comprises a preprocessing unit which carries out the frame dividing of a signal according to an initial audio signal collected by a microphone subarray, analyzes and calculates the short-time energy of each frame of the audio signal, obtains the noise frame and voice frame in an audio frame sequence, and obtains the signal to noise ratio of the audio frame sequence; a subarray selection unit which analyzes the direct-reverse ratio (DRR) of the signal received by each subarray of the microphone array, and selects the microphone subarray with the DRR being greater than a threshold value; a time delay calculation unit; a sound source positioning unit which carries out the pre-estimation of the position of the sound source according to the time delay of each microphone pair, and obtains a rough positioning module of a sound source space U; a precise positioning module which carries out the searching in the sound source space U, and obtains the maximum point of the improved controllable response power in the sound source space U. The system analyzes the positioning result of the plurality of microphone subarrays, and finally determines the position of the sound source through consistency processing.

Bring the Noise: Black Men Teaching (Race and) White Privilege

Abstract: In this article, we use autoethnography to reflect critically on our experiences, teaching race and White privilege at the collegiate level. Given our experiences as two Black male professors, we a...

Spatiotemporal patterns of avian vocal activity in relation to urban and rural background noise

Abstract: Background noise can interfere with and influence acoustic communication behavior. Signal interference is dependent on the amplitude and spectral characteristic of background noise, which varies over space and time. The likelihood of signal interference is greater when background noise is concentrated within the same frequency bands of an animal’s vocalization, but even a partial masking effect can elicit signaling behavior modification. Relative to a rural landscape, background noise in an urban landscape is disproportionately comprised by anthro- pogenic sound, which fluctuates in amplitude throughout the day and occurs primarily in low frequencies (0–2 kHz). In this study, we examined if urban-rural differences in vocal activity patterns exist in a species Zonotrichia leucophrys nuttalli that communicates above the frequency range of anthropogenic noise (2–8 kHz). We tested whether vocal activity patterns changed in relation to sound in the high or low frequency bands within and between urban and rural locations. Automated acoustic recording devices (ARDs) continuously recorded throughout the morning song chorus, 0500 to 1,100 h, during the 2014 breeding season in San Francisco (urban) and Marin (rural) Counties, CA. Supervised learning cluster analysis was used to quantify vocal activity by totaling the number of songs. In general, vocal activity was greater in urban locations com- pared to rural locations. However, within rural and urban study sites, we found vocal activity decreased where low frequency noise levels were higher. There was not a relationship between vocal activity and high frequency, biotic sound. In both urban and rural locations, low frequency noise levels increased through the morning, while vocal activity remained relatively consistent. Our results demonstrate how patterns of vocal activity can change with low frequency, abiotic noise, even when there is no direct spectral overlap with the acoustic signal.

Lombard effect onset times reveal the speed of vocal plasticity in a songbird

Abstract: Animals that use vocal signals to communicate often compensate for interference and masking from background noise by raising the amplitude of their vocalisations. This response has been termed the Lombard effect. However, despite more than a century of research, little is known how quickly animals can adjust the amplitude of their vocalisations after the onset of noise. The ability to respond quickly to increases in noise levels would allow animals to avoid signal masking and ensure their calls continue to be heard, even if they are interrupted by sudden bursts of high-amplitude noise. We tested how quickly singing male canaries (Serinus canaria) exhibit the Lombard effect by exposing them to short playbacks of white noise and measuring the speed of their responses. We show that canaries exhibit the Lombard effect in as little as 300 ms after the onset of noise and are also able to increase the amplitude of their songs mid-song and mid-phrase without pausing. Our results demonstrate high vocal plasticity in this species and suggest that birds are able to adjust the amplitude of their vocalisations very rapidly to ensure they can still be heard even during sudden changes in background noise levels.

Microtremor Response of a Mass Movement in Federal District of Brazil

Abstract: The present study provides a brief description of the ambient noise recorded at a slow moving mass movement in Ribeirao Contagem Basin. The area is an interesting natural laboratory as river detachment processes in a number of diferent stages can be identiied and are easily accessible. We investigate the site dynamic characteristics of the study area by recording ambient noise time-series at nine points, using portable nine three-component short period seismometers. The time-series are processed to give both horizontal to vertical spectral ratio (HVSR) curves as well as time-frequency plots of noise power spectral density (SPD). The HVSR curves illustrate and quantify aspects of site resonance efects due to the local geological setting. Probability density function (PDF) shows that noise level lies well between new high noise model (NHNM) and new lower noise model (NLNM) and their probabilities are higher above 2 Hz. HVSR curves present a uniform lithologically controlled peak at 2 Hz. Directional properties of the waveield are determined by beamforming method. The f-k analysis results in the E-W component show that at 5 Hz phase velocities are close to 1700 m/s while at 10 Hz dropped to 250 m/s. We observed that between 5 and 16 Hz the incoming waveield arrive from 260 degrees. Further studies will apply a detailed noise analysis for relating the dynamics of the landslide (which can be retriggered by river erosion as well as rainfalls and seismic shaking) to possible changes in detectable physical properties.

Listening to the din of the First World War

Abstract: In Great War texts, ranging from memoirs and journal articles to songs and novels, former soldiers comment not only on the extraordinary noise of the battlefield, but also on the importance of list...

Sound source positioning method and device and air conditioner

Abstract: The invention discloses a sound source positioning method and device, and the method comprises the steps: obtaining an audio signal received by a microphone array, wherein the microphone array comprises a plurality of microphones; obtaining the relative time difference between the audio signal received by any two of the plurality of microphones according to the audio signals and a preset parameter, wherein the preset parameter is set according to the SNR (signal to noise ratio); and carrying out the positioning of the audio signal according to the relative time difference between the audio signal received by any two of the plurality of microphones and the position of each microphone. The method can effectively and adaptively reduce the environment noise, has the strong capability of adapting to and resisting the reverberation and diffraction noise in a far-field environment, improves the recognition precision of a far-field sound source based on the microphone array, and improves the recognition practicality of the far-field sound source. The invention also proposes an air conditioner, a non-temporary computer readable storage medium, and a computer program product.

Exploring Convolutional Neural Networks for Voice Activity Detection

Abstract: This paper presents a voice activity detection (VAD) method based on convolutional neural networks (CNN). The proposed method uses the audio spectrogram raw image to detect frames of voice in specific audio signal. The spectrogram is split into frames, each of which is classified according to the presence or absence of voice. The proposed method achieved high accuracy in different noise conditions and was compared to state-of-the-art VAD methods. It outperforms the best VAD systems with a significant improvement in half-total error rate (HTER) when tested on the QUT-NOISE-TIMIT database. This technique indicates that using CNN on audio spectrogram images can be an efficient way for detecting voice even in extremely noisy audio signals.

Deep learning based automatic volume control and limiter system

Abstract: Automatic speech recognition is now playing an important role in volume control and adjustment of modern smart speakers. According to the recognition results by using the advanced deep neural network technology, this paper proposes an efficient processing system for automatic volume control (AVC) and limiter. The theoretical analyses, subjective and objective testing results show that the proposed processing system can offer a significant improvement for speech recognition performance during audio playback and improvement for audio playback performance in smart speakers. Driven by input data and audio contents, the proposed AVC is able to adaptively learn and track an effective signal level at the speed corresponding to the width of transient sound; the adaptation is frozen in the case of silence and noise periods. The proposed limiter measures the peaks and can guarantee that no peak will go over the predetermined peak threshold so as to avoid clipping and harmonic distortions.

Selective audio source enhancement

Abstract: A selective audio source enhancement system includes a processor and a memory, and a pre-processing unit configured to receive audio data including a target audio signal, and to perform sub-band domain decomposition of the audio data to generate buffered outputs. In addition, the system includes a target source detection unit configured to receive the buffered outputs, and to generate a target presence probability corresponding to the target audio signal, as well as a spatial filter estimation unit configured to receive the target presence probability, and to transform frames buffered in each sub-band into a higher resolution frequency-domain. The system also includes a spectral filtering unit configured to retrieve a multichannel image of the target audio signal and noise signals associated with the target audio signal, and an audio synthesis unit configured to extract an enhanced mono signal corresponding to the target audio signal from the multichannel image.

The Proliferation of Alarms in the Intensive Care Unit

Abstract: The proliferation of alarms on equipment in ICUs contributes to a level of noise that can disturb both patient and staff. To determine whether these alarms are indentiflable by sound alone to our ICU staff, we recorded 33 audio signals commonly heard on the ward, 10 of which we defined as critical alarms. One hundred subjects (25 physicians, 41 nurses, and 34 respiratory therapists) listened individually in a quiet room to the tape recording that consisted of 10 s of audible followed by a 10-s pause for a written response. Only 50 percent of the critical alarms and only 40 percent of the noncritical sounds were correctly identified. By occupation, registered respiratory therapists scored highest, followed by nurses, nonregistered therapists, and physicians.. Those with >1 year ICU work experience scored higher than those with less than 1 year. We conclude that the myriad of alarms that regularly occur in the ICU are too much for even experienced ICU staff to quickly discern. Patient and caregiver alike could benefit by a graded system in which only urgent problems have audible alarms, and these should be covered by regular in-service training. (Chest 1994; 105:1217-20)

Noise Reduction in Progressive Care Units.

Abstract: Uncontrolled noise in the hospital setting can have a negative physiological and psychological impact on patients and nurses. To reduce unit noise levels and create a quiet patient and nurse experience, an evidence-based practice project was conducted in 4 progressive care units in a community hospital. The Quiet Time Bundle implementation improved patient satisfaction and patient and nurse perceptions of noise even though the decrease in noise levels may not be discernible.

Analyses of crowd-sourced sound levels of restaurants and bars in New York City

Abstract: For several decades, there has been a significant need to better educate the public about noise pollution A small number of small-scale studies have focused on the sound levels of restaurants and their impact on health and hearing There have also been an increasing number of media articles stating that eating and drinking venues are getting increasingly loud making it more difficult for people to connect with others in conversation This study reports on an exploratory large-scale noise survey of sound levels of 2,376 restaurants and bars in New York City using a novel smart-phone application and categorized them based on how quiet or loud they were The results suggest that (1) a significant number of venues have high sound levels that are not conducive to conversation and may be endangering the health of patrons and employees (2) that the reported sound levels by the venue managers on their online public business pages generally underestimated actual sound levels, and (3) the average sound levels in r

Subjective perception of wind turbine noise - The stereo approach

Abstract: The conduct of stereo measurements for both playback in high-quality headphones and in a hemi-anechoic room has been undertaken for a number of wind farms and other low-frequency noise sources as an expansion of the material previously presented at the Boston ASA meeting. The results of the additional monitoring, evaluation, and subjective analysis of this procedure are discussed and identifies the benefits of monitoring noise complaints and assessments of wind farm noise in stereo. The laboratory mono subjective system was used to reproduce the audio wave file obtained in a dwelling. The test signal, being inaudible, was presented as a pilot double blind provocation case control study to 9 test subjects who have been identified as being sensitized to wind turbine noise and low frequency pulsating industrial noise. All test subjects could detect the operation of the inaudible test signal. The use of a stereo manikin to investigate detected inaudible “hotspots” is discussed.

Volume adjustment method and device and equipment

Abstract: The embodiment of the invention discloses a volume adjustment method and device and equipment. The method comprises the steps of obtaining environment noise through a microphone; triggering volume gain adjustment if the volume of the environment noise reaches a preset volume threshold value; adjusting a volume gain factor of an audio signal of at least one frequency band in to-be-played audio signals according to audio frequency characteristics of the to-be-played audio signals; and carrying out the volume gain adjustment on the audio signal through adoption of the volume gain factor of each frequency band. Through application of the technical scheme, an effect that the loudspeaking volume of a smart hardware device can match an external noisy environment smartly is achieved, and the user experience is improved.

Pre-echo noise reduction in frequency-domain audio codecs

Abstract: One of the most common yet detrimental compression artifacts in frequency-domain audio codecs is known as pre-echo, which is perceived as a brief noise preceding transient signals, and is discernable even without direct comparison to the original signal. Because of its substantial negative impact on audio quality, many techniques have been proposed to alleviate it, but not without effect on coding efficiency. This paper presents a novel method to reduce pre-echo noise using only information already available at the decoder, such as scale-factors, that allow an estimation of the quantization noise levels in each frequency band. Doing so allows the proposed method to reduce pre-echo noise based on a precise modeling of the quantization noise spread before the transient signal. This has shown to improve both the subjective and objective quality of the MPEG AAC codec, and requires no modifications to the existent standard-compliant encoders.

Do birds differentiate between white noise and deterministic chaos

Abstract: Noisy, unpredictable sounds are often present in the vocalizations of fearful and stressed animals across many taxa. A variety of structural characteristics, called nonlinear acoustic phenomena, that include subharmonics, rapid frequency modulations, and deterministic chaos are responsible for the harsh sound quality of these vocalizations. Exposure to nonlinear sound can elicit increased arousal in birds and mammals. Past experiments have used white noise to test for effects of deterministic chaos on perceivers. However, deterministic chaos differs structurally from white noise (i.e., random signal with equal energy at all frequencies), and unlike white noise, may differ dramatically depending on how it is produced. In addition, the subtle structural variation of chaos may not be distinguishable in the environment due to the attenuation and degradation of sound over distance and different habitat types. We designed two experiments to clarify whether American robins (Turdus migratorius) and warbling vireos (Vireo gilvus) discriminate between white noise and deterministic chaos. We broadcast and re-recorded white noise and two exemplars of deterministic chaos—one generated with a Chua oscillator and the other generated using a logistic equation—at 1, 10, 20, 30, 40, and 80 m across open and forested habitat and used spectrogram correlations to compare stimuli along this degradational gradient. We found that sounds degraded similarly in both habitats when compared to a reference distance of 1 m. Comparing pairs of stimuli across distances suggested that Chua chaos was more easily distinguishable from noise and logistic chaos. In addition, all stimuli became more distinctive over increased distance. The second experiment tested behavioral responses of robins and warbling vireos to control sounds of tropical kingbird (Quiscalus mexicanus), white noise, and two exemplars of deterministic chaos (Chua and logistic). Neither American robins nor warbling vireos responded differently to at least two types of deterministic chaos and white noise, validating previous playback studies that used white noise as a surrogate for deterministic chaos. Uniform responses to a variety of nonlinear features in these birds possibly reflect error management in alarm signal detection.

Low-latency smartphone app for real-time noise reduction of noisy speech signals

Abstract: This papers presents a low-latency smartphone app to achieve real-time noise reduction of speech signals in noisy sound environments. This app overcomes the two shortcomings of high latency and musical noise artifact that are associated with the previously developed apps for the same purpose. The results of both objective and subjective evaluations are reported which show the effectiveness of this app towards reducing noise for speech signals in noisy environments, in particular in babble background noise.