• The Journal of the Acoustical Society of Korea
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• v.39 no.2
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• pp.113-119
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• 2020

Motor noise is a major concern in order to improve perceptual feeling of car interior sound due to increased motor usage in passenger cars. The purpose of this study is to propose factors that can represent the acoustic performance of motor noise according to the change of load. To this end, at first, it is shown that power spectrum and total loudness are not fit for noise performance, and then, PN_B, partial loudness related to the brush friction component, and PN_R, partial loudness related to the torque ripple component are investigated as factors representing motor noise. The performance curve of motor noise using PN_B and PN_R is proposed to identify trends of motor noise according to the loads. The curve could be a guide for the noise control, the selection of motor, and the improvement of a system.

• International Journal of Internet, Broadcasting and Communication
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• v.9 no.2
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• pp.70-77
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• 2017

Where there are all the flowers, the songs of all kinds of insects and birds are put in, the sunshine and shadows flicker The forest through which the water sound flows is an optimum resting space. All living creatures in these spaces will awaken the five senses of humans and perhaps turn the sensibility index (EQ). The forest meditation in the forest, which can be an optimal shelter for the people who need it, needs to feel the reverence of nature, to refine emotions, to be a self-reflection, to have a mind to respect, Have an important meaning. In this paper, we tried to consider the cause of the influence of forest sounds on human hearing from the acoustical aspect. The type of sound source of forest was divided into four seasons of spring, summer, autumn, winter. And the change in the duration of the sound during the four seasons, so that the general characteristics of the sounds of the four seasons are as follows: It can be seen that the change in the ratio of sub-band energy is almost equal to the change in dB in frequency of the equal-light curve. To compare this phenomenon, the criterion for changing the sound duration of each forest is natural The main forms of the luminance curve, such as the change in the duration of the white signal in the sound, are determined by the minimum, maximum audible frequency and the most sensitive frequency band, and the auditory characteristics of the other three inflection points Determines the overall shape of the equal-light curve.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.4
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• pp.318-327
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• 2012

The operating sound radiated from a laser printer includes tonal noise components caused by the rotating mechanical parts such as gear, shaft, motor, fan, etc. The negative effects of the tonal noise components need to be considered in the process of developing a sound quality index for the quantitative evaluation of the emotional satisfaction in terms of psycho-acoustics. However, in a previous paper, it was confirmed that the Aures tonality did not have enough correlation with the results of jury evaluation. The sound quality index based on loudness, articulation index, fluctuation strength has a little problem in considering the effects of rotating mechanical parts on the sound quality. In this paper, to solve the tonality evaluation problem, the calculation algorithm of Aures tonality was investigated in detail to find the cause of decreasing the correlation. The new tonality evaluation model was proposed by modifying and optimizing the masking effect, loudness ratio, and shape of weighting curve based on the basic algorithm of Aures tonality, and applied to two kinds of operating sound groups in order to verify the usefulness of proposed model. As a result, it is confirmed that the proposed tonality evaluation model has enough correlation and usefulness for expressing the tonalness in the operating sounds of laser printers. In the following paper, this results will be used to model the sound quality index as the input data by using the classification algorithm.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.796-801
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• 2007

This research presents a laboratory study about a comparison between two methods that measure a hearing threshold of the Subjects who participated in an experiment of the Jury test. The Subjects heard a signal by a headphone. The Subjects of total 63 persons (man=42, woman=21 persons) participated in an experiment. A test of hearing was divided into two (Top-Down, Bottom-Up) methods. Total time of hearing test was about 80 minute(40min/day). As a results of the hearing test, a hearing threshold of the Subjects who used to wear a headphone was higher than that of the Subjects who not used to wear a headphone. A hearing threshold of a man was higher than that of a woman. The result of hearing test was showed that ISO's hearing threshold(MAF) was lower than a result that get from an experiment.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.11a
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• pp.260-261
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• 2010

본 논문에서는 제작된 콘텐츠에 배경음을 간편하고 효과적으로 혼합하기 위해서 녹음된 신호(전경음)를 분석하여 배경음 에너지를 적응적으로 조절하는 배경음혼합 알고리즘을 제안한다. 이를 위해, 제안된 알고리즘은 등청감 곡선 (equal-loudness curve) 및 linear prediction (LP) 분석에 기반하여 전경음신호의 청감 에너지 및 음성신호 존재여부를 결정한다. 이에 따라 전경음에 음성신호가 존재하는 경우에는 음성이 명확하게 들릴 수 있도록 혼합된 배경음의 에너지를 하향 조절하고, 반대로 전경음에 음성신호가 존재하지 않는 경우에는 배경음이 명확하게 들릴 수 있도록 혼합된 배경음의 에너지를 상향 조절한다. 제안된 알고리즘의 효율성을 검증하기 위해, 고정 가중치를 이용하여 배경음을 혼합하는 경우와의 음질 선호도 조사를 실시한 결과, 제안된 알고리즘에 대한 높은 선호도를 보였다.