Loudness Of Noise Research Articles

Comparison of Preferred Real-Ear Insertion Gain between Open- and Closed-Canal Fitting Hearing Aids

Purpose: To calculate the real-ear insertion gain (REIG) according to the types of hearing aids, we evaluated the preferred REIGs of Korean hearing-impaired listeners and psychoacoustic differences between open-canal fitting (OF) and closed-canal fitting (CF).Methods: The subjects with sensorineural hearing loss were divided into OF group (4 monaural fittings, 15 binaural fittings with 34 ears), and CF group (8 monaural fittings, 13 binaural fittings with 34 ears). There were no statistical differences in hearing threshold level (HTL) at each octave frequencies, word recognition score (WRS) and Korean Adaptation of the International Outcome Inventory for Hearing Aids (K-IOI-HA) between the two groups. When there was no need for further electroacoustic adjustment of the hearing aid, sharpness and occlusion of amplified sound, clarity of sentence, and loudness of noise were evaluated based on the everyday experience. And REIGs with international speech test signal and WRS in sound-treated room were measured.Results: Preferred REIG for HTL was low for OF compared to CF in 0.5 kHz and 0.75 kHz at input SPL of 55 dB, 0.5 kHz at 60 dB SPL, 0.25 kHz and 0.5 kHz at 80 dB SPL. However, there were no differences in aided WRS and psychoacoustics between the two groups.Conclusion: In this study, the preferred REIG of OF and CF groups showed a difference under 0.75 kHz although there were no psychoacoustic differences between the two groups. Therefore, the results of this study should be considered when formulating Korean-type hearing aid fitting formula.

Changes of the Korean Consonant-Vowel Syllabic Recognition Scores According to the Compression Threshold Control of Multi-Channel Hearing Aid

Purpose: While adjusting the compression threshold (CT) of low and high frequency bands of multi-channel hearing aids in noise, we tried to evaluate any changes in Korean consonant-vowel (CV) syllabic recognition scores, sound quality, and loudness of noise with white noise.Methods: A total of twenty one subjects with hearing loss (mean age of 66.2 years) participated voluntarily. Their pure-tone average was 46.0 dB HL and the word recognition score was 72.1%. The CTs of low/high frequency bands were adjusted to 50/50 dB SPL, 50/65 dB SPL, 65/50 dB SPL and 60/65 dB SPL in multi-channel hearing aids. While presenting white noise to the non-test ear, Korean CV syllables were presented to the test ear to evaluate the recognition scores, clarity of conversational speech, and loudness of noise. The intensity of CV syllables presented to the subject was 50 dB HL, and the signal-to-noise ratios (SNRs) were 5 dB and 10 dB.Results: First, when the CT of low/high frequency bands was adjusted to 50/50 dB SPL, the CV syllabic recognition scores were higher compared to 65/50 dB SPL. Second, in the noise environment, the clarity of conversational speech, and loudness of the noise did not have any difference regardless of levels of CT.Conclusion: Based on current findings, the frequency bands setting of CT in the multi-channel hearing aids might provide changes to recognize Korean speech sounds, which may affect the adjustment of frequency band CT from multichannel hearing aids in the future.

The perceptual and behavioral influence on dental professionals from the noise in their workplace

A long-term exposure to the high-frequency dental noise is a potential hazard to the health of dental professionals and the quality of oral health service provisions. This study aims to thoroughly investigate the influence of an acoustic environment on the perceptions and behaviors of dental professionals. A multidimensional sound quality assessment that comprises the objective measurements of the acoustic and psychoacoustic metrics in different statistical levels and a self-administrated questionnaire was conducted in the Prince Philip Dental Hospital of Hong Kong. The results indicate that the dental professionals’ noise sensitivity and job-performance drops are mainly affected by loudness of noise. Moreover, two types of health risk perceptions, loudness-related and sharpness-related, were found to be associated with a health state of dental professionals. Also, a higher chance of having health-mediated avoidance was found for the dental professionals who had a worse health state and worked in a noisier workplace. These findings provide new knowledge on the development of a health-supportive acoustic environment.

Effects of adding natural sounds to urban noises on the perceived loudness of noise and soundscape quality

Introducing pleasant natural sounds to mask urban noises is an important soundscape design strategy to improve acoustic comfort. This study investigates the effects of signal-to-noise ratio (SNR) between natural sounds (signal) and the target noises (noise) and their temporal characteristics on the perceived loudness of noise (PLN) and overall soundscape quality (OSQ) through a laboratory experiment. Two types of urban noise sources (hydraulic breaker and traffic noises) were set to A-weighted equivalent sound pressure levels (SPL) of 55, 65, and 75 dB and then augmented with two types of natural sounds (birdsong and stream), across a range of SNRs. Each acoustic stimulus was a combination of noise and natural sound at SNRs from −6 to 6 dB. Averaged across all cases, the subjective assessment of PLN showed that augmenting urban noise separately with the two natural sounds reduced the PLN by 17.9%, with no significant differences found between the birdsong and stream sounds. Adding natural sounds increased the OSQ by on average 18.3% across the cases, but their effects gradually decreased as the noise level increased. The OSQ of the birdsong and stream sounds were similar for traffic noise, whereas the stream sound was rated higher than the birdsong for the breaker noise. The results suggest that increasing the dissimilarity in temporal structure between the target noise and natural sounds could enhance the soundscape quality. Appropriate SNRs were explored considering both PLN and OSQ. The results showed that the SNR of −6 dB was desirable when the A-weighted SPL of the noise rose to 75 dB.

The effects of spatial separations between water sound and traffic noise sources on soundscape assessment

Many studies have investigated the effects of water sound on soundscape with an assumption that target noise coincides with the masker (co-location), while no attention has been paid to spatial separations between target noise and water sound sources. This study aims to explore the effects of spatial separations between target noise and water sound on perceived loudness of target noise (PLN) and overall soundscape quality (OSQ) through laboratory experiments. Traffic noise (target) and a water sound (masker) were recorded as acoustic stimuli and a spherical panoramic video recording of a water fountain was also used as visual stimuli. The audio-visual stimuli were reproduced through a virtual reality head-mounted display and a multichannel ambisonic loudspeaker setup. The traffic noise and water sound were played simultaneously at various azimuthal separations and were combined with a panoramic recording of a water fountain as visual stimulus. Participants assessed the audio-visual stimuli in terms of PLN and OSQ. The effect of the spatial separation between the traffic noise and water sound was significant in both PLN and OSQ. Specifically, the PLN increase at 135° separation was equivalent to an estimated target noise level increment of ~1–2 dB. Similarly, the OSQ decrease at 135° and 180° separation was equivalent to an estimated target noise level increase of ~2–5 dB. Since the typical field of view of users in space is less than 135°, the results suggest that placing water features within a user's field of view could achieve better soundscape.

Directional Loudness of Low-Frequency Noises Actually Presented Over Loudspeakers And Virtually Presented Over Headphones

Directional Loudness of Low-Frequency Noises Actually Presented Over Loudspeakers And Virtually Presented Over Headphones

Analysis on loudness of exhaust noise and improvement of exhaust system based on structure-loudness model

The structure of exhaust system influences the loudness of exhaust noise significantly. This paper indicates the impact of the structure parameters of exhaust system on the loudness of exhaust tail noise and presents an evaluation model to conduct the improvement of exhaust system for improved loudness. Firstly, the twenty-seven structure samples are designed by orthogonal experiment and exhaust tail noises of those are obtained by simulation. The accuracy of simulation is also validated by the experiment successfully. Then the structure-loudness model is developed by the radial basis function (RBF) network technique. Subsequently, the contributions and main effects of the structure parameters on loudness are indicated in this work. Finally, based on the structure-loudness model, the robust optimum design for improved loudness is studied by the adaptive simulated annealing (ASA) algorithm. The result of optimization certifies that the structure-loudness model is useful for the optimization. The method applied in this paper can be feasible for other psychoacoustic metrics.

Changes of Non-Sense Syllabic Word Scores and Preferences as a Function of Release Time on Multi-Channel Hearing Aids

Purpose To determine the effective release time (RT) for listening to Korean sounds when wearing hearing aids, we evaluated Korean non-sense syllabic word recognition scores (NSRS) and the clarity of conversation sounds, the size of noise, and the overall preferences as a function of RT. Methods Twenty adults and elderly people with mild to severe sensorineural hearing loss were participated as subjects. In the quiet and noise environment, NSRS and preferences were evaluated after setting the RT of the multi-channel hearing aids to 70, 200, and 600 ms. Presentation level of non-sense syllabic word was 45 dB HL and signal-to-noise ratio was 6 dB in noise environment. Results NSRS was not different as a function of RT in quiet, but NSRS of 200 ms was higher than 70 ms and 600 ms in noise environment. However, clarity, loudness of noise, and overall preference did not show a difference in RT in a quiet and noisy environment. Conclusion Through this study, it was confirmed that Korean NSRS can be affected by RT. Therefore, in order to develop a hearing aid fitting formula that is effective in recognition of Korean speech sound, it is necessary to consider the RT. Key Words: Hearing aids, Release time, Compression threshold, Compression ratio, Hearing aid fitting formula 중심 단어: 보청기, í•´ì œì‹œê°„, 압축역치, 압축비율, ë³´ì²­ê¸°ì í•©ê³µì‹

Sound quality metrics applied to road noise evaluation

Road noise monitoring systems typically measure sound levels in specific time periods. The more insightful approach suggests to measure also the nature of noise. Sound quality of sounds such as car noise can be objectively evaluated by several parameters. One of them is psychoacoustic annoyance, described by loudness, tone color, and the temporal structure of sound. In this paper the assessment of several sound quality parameters, such as: loudness of time-varying noise, sharpness, fluctuation strength, and roughness, as well some additional parameters borrowed from the Music Information Retrieval area are presented. Then a comparison between parameter values obtained by means of the professional measurement system and a tool working in the Matlab environment is performed. The conducted investigations are carried out using recorded samples of an individual vehicle pass-by in close proximity of the road, organized as a database of road traffic noise recordings. [This research was partly supported by the Polish National Centre for Research and Development within the Grant No. OT4-4B/AGH-PG-WSTKT.]

A basic research on expression of loudness and orientation of sound source in soundscape by onomatopoeia on pictures

When soundscape is described with words under common acoustic environment, it is usual that the name of the sound source that indicates their category or species is noted. Generally, such kind of description cannot express loudness and orientation of sound source. However, the information of loudness and orientation of the sound source is important, so it is necessary to note them easily at a time. In the present research, it is investigated whether description of soundscape using onomatopoeia on pictures to express loudness and orientation of sound sources is effective or not. Two psychological experiments are carried out to reveal the availability of this description method. Results show that onomatopoeia can present the type of source, and that it can simultaneously express variety of loudness of sound source and noise. It is suggested that the size and number of onomatopoeia described on pictures of the place where noise exists represents loudness of sound and noise, and that the variety of size of on...

Effects of indoor temperature and background noise on floor impact noise perception

This study investigates effects of room air temperature and background noise on the perception of floor impact noises in a room. Floor impact noises were recorded in apartment buildings and were presented in an indoor climate chamber with background noise for subjective evaluation. Thirty-two participants were subjected to all combinations of three thermal conditions (20%C, 25%C, 30%C and relative humidity 50%), four background noise types (Babble, Fan, Traffic and Water), three background noise levels (35 dBA, 40 dBA and 45 dBA) and four floor impact noises (Man Jumping, Children Running, Man Running and Chair Scraping). After a 1-h thermal adaptation period for each thermal condition, the participants were asked to evaluate their thermal and acoustic perceptions. Statistically significant effects were found for the room air temperature and background noise level on the perception of the floor impact noises. Noisiness, loudness and complaints of floor impact noise increased with increasing room temperature and background noise level. Annoyance of floor impact noise showed a peak in acceptable thermal environment for general comfort. Room air temperature was a dominant non-auditory factor contributing to floor impact noise annoyance, while the floor impact noise level influenced the floor impact noise loudness and the floor impact noisiness was almost equally affected by the room temperature, background noise level and floor impact noise level. Further investigation is needed to fully understand the combined perception of floor impact noise under various indoor environmental conditions.

Research on Loudness of Radiation Noise of a Constrained-Layer Damping Oil Pan

Research on Loudness of Radiation Noise of a Constrained-Layer Damping Oil Pan

The effects of auditory object identification and localization (AOIL) training on noise acceptance and loudness discomfort in persons with normal hearing

ABSTRACTThis study investigated the changes in Acceptable Noise Levels (ANLs) and Loudness Discomfort Levels (LDLs) after at home use of Auditory Object Identification and Localization auditory training (AOIL, [Searchfield, Morrison-Low, & Wise, 2007]. Object identification and attention training for treating tinnitus. Progress in Brain Research, 166, 441–460. doi:S0079-6123(07)66043-9 [pii]).Methods: A crossover design was used to compare LDLs and ANLs measured in 40 participants (16 male 24 female, average age 24, SD 2.5 years) with normal hearing, prior to and after 15 days of training and 15 days of no training (control). The auditory training consisted of identifying a mixture of environmental sounds or speech stimuli against various background noises from three different virtual locations (left, right, center). The participants listened to the training stimuli using Philips GoGear Vibe personal music players and recorded their responses on a training record sheet.Results: A significant training-specific decrease (improvement) in ANLs was found, but no change in LDLs was observed.Summary: The results indicate that the AOIL training program improved noise acceptance, but did not affect LDLs, in persons with normal hearing. The training task should be investigated for use as a therapeutic tool in persons with ‘annoyance hyperacusis’.Abbreviations: ANL: Acceptable Noise Level; MCL: Most Comfortable Level; BNL: Background Noise Level

Loudness summation of equal loud narrowband signals in normal-hearing and hearing-impaired listeners

Objective: Loudness perception of binaural broadband signals, e.g. speech shaped noise, shows large individual differences using frequency-dependent amplification which was adjusted to restore the loudness perception of monaural narrowband signals in hearing-impaired (HI) listeners. To better understand and quantify this highly individual effect, loudness perception of broadband stimuli consisting of a number of spectrally separated narrowband components which where individually adjusted to equal loudness is of interest. Design: Based on categorical loudness scaling, the loudness of an equal categorical loudness noise (ECLN) consisting of six third-octave noises was assessed. For loudness categories “medium” und “very loud” the required narrowband loudness was analysed. Study sample: Nine normal-hearing (NH) and ten HI listeners. Results: HI listeners showed lower narrowband loudness values compared to NH listeners, indicating an increased spectral loudness summation. More than 50% of the HI listeners showed higher binaural spectral loudness summation compared to NH listeners. The amount of binaural spectral loudness summation was highly correlated (r2 = 0.92) with the loudness level at “very loud” of aided speech shaped noise. Conclusions: The suggested ECLN measurement is suited to assess individual (binaural) broadband loudness in aided conditions, providing valuable information for hearing-aid fitting.

Preferred Compression Threshold and Release Time in Quiet and Noisy Conditions for Elderly Korean Hearing Aid Users.

Background and ObjectivesListeners with sensorineural hearing loss want to compensate for their narrow dynamic range from appropriate compression functions of hearing aids. The present study aimed to determine which compression threshold and release time of nonlinear hearing aids might affect speech recognition and speech quality judgments.Subjects and MethodsTen elderly listeners with symmetrical moderate-to-severe sensorineural hearing loss participated in the study. To compare two compression threshold (31 dB SPL vs. 61 dB SPL) and two release time (50 ms vs. 500 ms) conditions, subjects’ speech recognition was measured using the Korean version of the Hearing in Noise Test in both quiet and noisy situations. All subjects were also asked to rate the degree of speech quality in terms of loudness, sharpness, clarity, and background noise immediately after completing the speech recognition test.ResultsAlthough no significant difference emerged in speech recognition thresholds between the two compression thresholds in the quiet situation, the compression threshold of 31 dB SPL showed a lower (or better) signal-to-noise ratio of speech recognition compared to that of 61 dB SPL. The release times of 50 and 500 ms did not statistically differ in both quiet and noisy situations. Subjective categories were found to be louder and clearer in the 50 ms release time for quiet and noisy, respectively.ConclusionsWe expect that these patterns of current results will apply for better-fitting protocol of elderly Korean hearing aid users.

How tonality and loudness of noise relate to annoyance and task performance

Audible tones in noise generated by building mechanical equipment can be a leading cause of complaints from occupants. A number of metrics have been developed to quantify prominence of a tone, but previous work has shown that the impact of a certain tonality appears to vary with the level of the broadband noise signal. More work on how tonal signals of varying tonality, tone frequency and broadband noise levels relate to annoyance and task performance is needed. This paper investigates such relationships between current noise metrics, annoyance and task performance under assorted tonal noise conditions through subjective testing. Participants rated their perceived annoyance after being exposed to noise signals with differing levels of tones while solving Sudoku puzzles. In addition to assessing annoyance, the test also surveyed the perceived workload caused by the noise by using a modified noise-induced task load index questionnaire. Five levels of tonal prominence for each of two tonal frequencies were added above two different ambient background noise levels to create 20 noise signals of interest. The task performance results based on the Sudoku puzzle answers show trends of decreasing accuracy with increasing tone strengths, but the differences are not statistically significant. Other findings are that loudness metrics are most highly correlated with annoyance responses, while tonality metrics demonstrate relatively less but also significant correlation with annoyance. Generally, participants felt more annoyed with higher background noise levels, lower tone frequency and more prominent tone strength. Based on correlation analysis, a multiple regression model using two of the most strongly correlated noise metrics, ANSI loudness level and tonal audibility, has been developed for predicting annoyance responses from tonal noise conditions.

Experimental studies on speech level and room acoustic condition focusing on speech privacy

Recently, concerns about speech privacy to avoid oral information leakage at medical facilities are increasing continuously in Japan. In order to achieve the requirements of the speech privacy, standardization has also been discussed. On discussing the speech privacy, speech level is one of the most important factors. This study investigated the speech levels of Japanese talkers and the relationships between the speech levels and the room acoustic conditions (reverberation time, ratio of direct and reflected sound, and loudness of background noise). Subjective experiments were conducted under three conversation conditions; normal voice level with a partner sitting 1 m away, raised voice level with the partner sitting 3 m away, and voice level considering overhearing about the contents by a third party. Acoustic environments were reproduced in an anechoic room with a binaural sound field simulation system. As a result, the speech levels of the three conversation conditions were varied. In the simulated test conditions, it was revealed that the room acoustic conditions affected on the speech levels, but the changes of the levels were small.

Subjective and objective acoustic performance ranking of heavy and light weight walls

This study presents a comparison between heavyweight and lightweight walls, in terms of perceived loudness of pink noise transmitted through 10 different walls. The objective is to investigate whether the single number descriptor RA,50–5000 adequately reflects the subjective perception of the acoustic performance of a wall and if the sound reduction index spectral behaviour affects the subjective rating. To perform the experiment, a Matlab® based digital tool was developed and a pairwise comparison listening test was performed in laboratory conditions with thirty three subjects. The sound samples consisted of only one stimulus – pink noise-, filtered by the sound reduction index spectrum of 5 heavy weight walls and 5 corresponding lightweight walls with the same RA,50–5000 but different Rw.The results were analysed and used to rank the walls from best to worst according to the perceived loudness of the sound samples. It has been shown that lightweight walls are better ranked than heavy walls, not only when compared to those with the same RA,50–5000, but in some cases also when the RA,50–5000 of the heavy wall is higher than the RA,50–5000 of the lightweight one. Furthermore, the ranking obtained from the listening test results matches very well with the ranking made according to Rw+C≈RA,100–3150.

Polyphony beyond the Human: Animals, Music, and Community in Coetzee and Powers

Although most literary scholars are familiar with Mikhail Bakhtin's argument about how the orchestrates polyphonic symphony of socially diverse voices, our account of these voices, and of novelistic sound more generally, remains far from complete. Aiming to address these gaps in recent pamphlet of the Stanford Literary Lab, Hoist Katsma has reinvigorated Bakhtin's insights with the help of quantitative reading protocols to describe the patterned of the nineteenth-century (13), paying special attention to Dostoevsky's The Idiot (1869). Though I will argue that Katsma's argument is ultimately flawed because it overlooks technological and biological sounds, making this model unfit for my central case studies, novels by J. M. Coetzee and Richard Powers, the pamphlet rightly emphasizes the structural role of sound in prose fiction as well as the importance of the reader's aural experience. Katsma also proposes several hypotheses that invite further research: that loud in the nineteenth-century usually come from individuals rather than groups; that certain grammatical structures (involving commands, questions, em dashes) are better indicators of loudness than specific speaking verbs such as whisper or shout; that loudness is organized in the novel, as its quasi-musical polyphony of is systematically related to plot structure, narrative space, and chapter divisions (16); and that the quantitative analysis of this loudness reveals general muting of the over the course of the 19th century (21). This pamphlet hence illustrates how new digital techniques can enrich existing insights in literary studies. But Katsma's argument shows flaws as well. Without further reflection, he dismisses the existing work on sound in literature, confidently claiming that little has come of the study of sound in the novel (2). If he would have considered the work of scholars the intersection of literary studies and sound studies, like that of John Picker, Philipp Schweighauser, or Justin St. Clair, Katsma might also have been able to complicate his further assumption that sound in the can be reduced to the voices of narrators and characters (1): at the level of textual mechanics, novel's aural trajectory, heard by the reader, is created via the novel's string of consecutive (10). In his view, the words of storytellers and characters are quasi-heard in our minds, whereas the music, noise, and other environmental described by these words are not part of the novel's soundscape all. In footnote, Katsma admits that sometimes these human ask the reader to imagine secondary sounds via the description of raindrops, for instance, but these are supposedly less intense, fleeting and rather infrequent in every form of literature (2). This dismissal of described sound is unsatisfactory because Katsma's lopsided focus on human might explain why he finds growing stillness where others discover increasing loudness. Whereas his analysis of suggests gradual muting of the during the nineteenth century, as I mentioned, John Picker's account of described rather than imagined dialogue reaches the opposite conclusion; as fictional and other documents show, he confidently states, the Victorian age was a period of unprecedented amplification, unheard-of alive with the screech and roar of the railway and the clang of industry, with the babble, bustle, and music of city streets, and with the crackle and squawk of acoustic vibrations on wires and wax (4). Katsma fails to consider, in other words, that the growing stillness of human characters might be related to the increasing loudness of urban noise. The fact that the opening scene of The Idiot is set on train, for instance, is taken to have no implications for the sequence's loudness, even though the text mentions that it is travelling full speed and with crowded compartments. …

Quiet transcranial magnetic stimulation: Status and future directions.

A significant limitation of transcranial magnetic stimulation (TMS) is that the magnetic pulse delivery is associated with a loud clicking sound as high as 140 dB resulting from electromagnetic forces. The loud noise significantly impedes both basic research and clinical applications of TMS. It effectively makes TMS less focal since every click activates auditory cortex, brainstem, and other connected regions, synchronously with the magnetic pulse. The repetitive clicking sound can induce neuromodulation that can interfere with and confound the intended effects at the TMS target. As well, there are known concerns regarding blinding of TMS studies, hearing loss, induction of tinnitus, as well as tolerability. Addressing this need, we are developing a quiet TMS (qTMS) device that incorporates two key concepts: First, the dominant frequency components of the TMS pulse sound (typically 2-5 kHz) are shifted to higher frequencies that are above the human hearing upper threshold of about 20 kHz. Second, the TMS coil is designed electrically and mechanically to generate suprathreshold electric field pulses while minimizing the sound emitted at audible frequencies (<; 20 kHz). The enhanced acoustic properties of the coil are accomplished with a novel, layered coil design. We summarize a proof-of-concept qTMS prototype demonstrating noise loudness reduction by 19 dB(A) with ultrabrief pulses at conventional amplitudes. Further, we outline next steps to accomplish further sound reduction and suprathreshold pulse amplitudes.