Indoor Acoustic Signals Enhanced Algorithm and Visualization Analysis

A pure acoustic signal can be easy to realize signal analysis and feature extraction. However, the surrounding noises will affect the content of acoustic signals as well as auditory fatigue to the audience. Therefore, it is vital to overcome the problem of noises that affect the acoustic signal. An indoor acoustic signal enhanced method based on image source (IS) method, filtered-x least mean square (FxLMS) algorithm, and the combination of Delaunay triangulation and fuzzy c-means (FCM) clustering algorithm is proposed. In the first stage of the proposed system, the IS method was used to simulate indoor impulse response. Next, the FxLMS algorithm was used to reduce the acoustic signals with noise. Lastly, the quiet areas are optimized and visualized by combining the Delaunay triangulation and FCM clustering algorithm. The experimental analysis results on the proposed system show that better noise reduction can be achieved than the most widely used least mean square algorithm. Visualization was validated with an intuitive understanding of the indoor sound field distribution and the quiet areas.

Auditory fatigue among call center operators with headset

Background To assess whether call center operators are subject to or suffer from any auditory fatigue when compared to normal subjects. A prospective case-control study where twenty-eight call center operators (10 females and 18 males) with an age range from 25 to 46 years and twenty controls (12 females and 8 males) with an age range from 23 to 44 years were included. All call center operators use a headset for up to 8 h daily for a minimum of two consecutive years. Audiological assessments were done to all participants that included pure tone audiometry (PTA), speech audiometry, tympanometry, and acoustic reflexes. Moreover, transient-evoked otoacoustic emission (TEOAE) absolute threshold and distortion product otoacoustic emission (DPOAE) signal to noise thresholds as well as contralateral suppression of TEOAEs and DPOAEs were recorded for both groups. Results There was no significant variation in auditory performances detected with either PTA or OAE (TEOAEs and DPOAEs) test. Besides, there was no statistically significant difference in OAEs (TEOAEs and DPOAEs) with contralateral suppression for both the call center operators and control groups. However, call center operators expressed a feeling of tiredness. Conclusions There was no detectable central or peripheral auditory fatigue experienced by the call center operators when using headsets. However, their sensation of auditory fatigue could be due to cognitive fatigue rather than noise-induced fatigue.

What is noise-induced hearing loss?

Noise-induced hearing loss is sensory deafness caused by long-term exposure of the auditory system to a noisy environment. Auditory fatigue is an early symptom of noise-induced hearing loss, and hearing can gradually recover after people leave a noisy environment. However, if people remain in a noisy environment for a prolonged period of time, their hearing will be permanently impaired. Societal changes mean that people are more likely to be exposed to noise. The hearing loss and tinnitus caused by noise seriously affect people's quality of life and lead to huge economic loss. The pathogenesis of noise-induced hearing loss is complex. Various theories try to explain this, such as the oxidative stress theory, but none perfectly explains the occurrence of noise-induced hearing loss. There is no treatment which can completely reverse the damage. More research is required to explore the pathogenesis and to better guide clinical practice. Preventative strategies, such as educating the public about hearing health, should be adopted to reduce the harm of noise-induced hearing loss.

DAMPAK KELELAHAN AUDITOR TERHADAP PERILAKU KEWARGANEGARAAN ORGANISASIONAL: PENGUJIAN KOMITMEN PROFESSIONAL DAN KEPUSAAN KERJA SEBAGAI VARIABEL PEMEDIASI

Studies show that Organizational Citizenship Behavior (OCB) becomes an important part of an organization's sustainability, even to the individualistic level. But it is difficult to realize with this intention when workers experience high levels of work fatigue, because of excessive workload This study aims to investigate the impact of the Auditor Burnout or auditory fatigue in OCB aspect, which also investigates the dimensions that mediate between two aspects namely professional commitment and satisfaction of work simultaneously. This study uses primary data, where surveys are distributed to auditors working in public accounting firms that have international affiliations. The number of samples is 150 auditors. This study uses a survey to collect data and the data collected is then analyzed using SEM. The findings of this study indicate that auditor fatigue, mediated by professional commitment and job satisfaction, will have a negative impact on OCB. It can be concluded that auditors will experience fatigue or lack of application to OCB.

Perception of Changes in Spectrum and Envelope of Musical Signals vs Auditory Fatigue

The paper presents results of research on an influence of listening fatigue on the detection of changes in spectrum and envelope of musical samples. The experiment was carried out under conditions which normally exist in a studio or on the stage when sound material is recorded and/or mixed. The equivalent level of presented sound samples is usually 90 dB and this is an average value of sound level existing in control room at various recording activities. Such musical material may be treated as a noise so Temporary Threshold Shift phenomenon may occur after several sessions and this may lead to a listening fatigue effect. Fourteen subjects participated in the first part of the experiment and all of them have the normal hearing thresholds. The stimuli contained the musical material with introduced changes in sound spectrum up to ±6 dB in low (100 Hz), middle (1 kHz) and high frequency (10 kHz) octave bands. In the second part of research five subjects listened to musical samples with introduced envelope changes up to ±6 dB in interval of 1 s. The time of loud music exposure was 60, 90 and 120 minutes and this material was completely different from the tested samples. It turned out that listening to the music with an Leq= 90 dB for 1 hour influences the hearing thresholds for middle frequency region (about 1-2 kHz) and this has been reflected in a perception of spectral changes. The perceived peaks/notches of 3 dB have the detection ability at 70% and the changes of low and high ranges of spectrum were perceived at the similar level. After the longer exposure, the thresholds shifted up to 4.5 dB for the all investigated stimuli. It has been also found that hearing fatigue after 1 hour of a listening influences the perception of envelope which gets worse of 2 dB in comparison to the fresh-ear listening. When time of listening to the loud music increases, the changes in envelopes which can be detected rise to the value of 6 dB after 90-minutes exposure and it does not increase with further prolongation of listening time.