• 한국소음진동공학회논문집
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• 제16권5호
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• pp.485-494
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• 2006

The state-of-the-art of low-noise fan design usually includes the consideration of optimal sound level and sound quality. The influential design parameters of the noise level by the centrifugal fan were selected based on the preliminary test. The centrifugal fans were designed according to the experiment plan method by specifying the selected design parameters. The experiment with these machined mock-up's of centrifugal impellers suggested the major design parameters among many, having impacts upon the indices of sound quality (e.g. loudness, sharpness, roughness and fluctuation strength) at the same operation point. With the response surface method, the major design parameters selected thereafter were analyzed to estimate each contribution upon the sound quality of the centrifugal fan, and the optimal values were drawn by the consideration of the sound quality levels and their regression equations. In addition, the validity of the regression equations was numerically verified by means of the coefficient of determination. Furthermore, the mechanism by which the centrifugal fan impeller influences the determinants of its sound quality was suggested.

• Fibers and Polymers
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• 제6권1호
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• pp.89-94
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• 2005

The purpose of this study is to offer acoustical database of warp knitted fabrics by investigating frictional sound properties and physiological responses according to structural parameters such as construction, lap form, and direction of mutual guide bar movement. Fabric sounds of seven warp knitted fabrics are recorded, and Zwicker's psychoacoustic param­eters - loudness(Z), sharpness(Z), roughness(Z), and fluctuation strength(Z) - are calculated. Also, physiological responses evoked by frictional sounds of warp knitted fabrics are measured such as electroencephalogram (EEG), the ratio of high fre­quency to low frequency (HF/LF), respiration rate (RESP), skin conductance level (SCL), and photoplethysmograph (PPG). In case of constructions, frictional sound of sharkskin having higher loudness(Z) and fluctuation strength(Z) increases RESP. By lap form, open lap has louder and larger fluctuating sound than closed lap, but there aren't significant difference of physi­ological responses between open lap and closed lap. In direction of mutual guide bar movement, parallel direction evokes bigger changes of beta wave than counter direction because of its loud, rough, and fluctuating sound. Fluctuation strength(Z) and roughness(Z) are defined as important factors for predicting physiological responses in construction and mutual guide bar movement, respectively.

• 한국음향학회지
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• 제36권1호
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• pp.78-87
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• 2017

본 논문에서는 심리음향학적 연구 방법론을 음악의 작품 분석에 적용하여 음악의 매개체인 소리에 내재된 주관성을 객관화하고자 한다. 먼저, 대표적인 표제음악인 베를리오즈의 '환상교향곡'에서 18개의 샘플음원을 추출한 다음 쯔비커의 음질 파라메터(Loudness, Sharpness, Roughness, Fluctuation Strength)를 이용해서 샘플음원의 객관적 음질을 평가하였다. 주관적 음질 평가를 위하여 환상교향곡의 표제성을 기초로 9개의 대표 음질형용사를 추출한 다음 수치등급평가법과 쌍대비교법을 사용하여 1차 청음평가를 수행하였다. 1차 청음평가결과의 요인분석법을 통하여 "밝은", "시끄러운", "현실적인"의 세 가지 음질을 추출하였다. 세 가지 음질 형용사를 사용하여 2차 청음평가를 수행하고 그 결과를 객관적 음질 파라메터와 상관분석을 수행하여 음질지표를 개발하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.826-829
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• 2005

The State of the art of low noise fan design requires the consideration of optimal sound quality. The influential design parameters of the noise level by the centrifugal fan were selected that based on a preliminary test. The centrifugal fans were designed according from the experiment plan method by specify the selected design parameters. The experiments with the machined mock-up's of centrifugal impellers revealed the major design parameters having impacts upon the indices of sound quality (e.g. loudness, sharpness, roughness and fluctuation strength) at the same performance condition. With a response surface method. the major design parameters selected were analyzed to estimate their contributions upon the sound quality of the centrifugal fan and the optimal values were drawn for the consideration of the sound quality by using each level and its regression equation. In addition, the validity of the regression equations were numerically verified by means of the coefficient of determination. Furthermore, the mechanism of how the centrifugal fans influence the determinants of sound quality was suggested.

• 소음진동
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• 제10권2호
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• pp.345-352
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• 2000

최근 여객선이 고속화, 고금화되고 있는 추세에 따라 선실내 소음 저감이 중요한 설계 요소로 간주되고 있다. 일반적으로 선박 소으믄 음암레벨로 평가되나 여객선의 경우 승객에게 더욱 쾌적한 환경을 제공하기 위하여 음질을 개선할 필요가 있다. 본 연구에서는 연근해를 운항 중인 기존 고속 여객선의 소음을 계측하고, 정신음향학 분야에서 제시된 Zwicker Loudness 계산식에 의거하여 음의 크기, 거칙기, 변동세기 및 날카로움으로 음질을 평가하였다. 또한, 각각의 음질 평가요소와 음압간의 상관관계를 분석하였다. 상기 결과로부터 고속여객선의 음의 크기는 음압과 비례하는 반면에 음의 거질치 (roughness),변동세기(fluctuation strength)및 날카로움(sharpness)은 선박의 운동과 추락변동 등으로 인하여 음압과 비선형적인 상관관계를 나타냄을 확인하였다.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 2003년도 춘계학술대회 논문집
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• pp.8-13
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• 2003

Frictional sound of 13 vapor permeable water repellent fabric by sound generator were recorded and analysed through FFT analysis. The frictional Sounds were quantified by calculating total sound pressure(LPT), the level range ΔL and the frequency difference Δf. Mechanical properties were measured by KES-FB. LPT values of specimens finished wet coating were higher than those of dry coating. Values for bending rigidity, shear stiffness, surface roughness and compressional recovery of polyurethane fabrics increased compared with the cire finished fabrics. Laminated fabrics had high values of frictional coefficient and low values of surface roughness. LPT showed significant correlation with compressional energy, weight and thickness. (ΔL) was highly correlated with compressional linearity, frictional coefficient, compressional recovery, and (Δf) with tensile linearity, compressional energy, thickness, and weight.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.671-674
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• 2006

Heavy-weight impact sounds generated by impact ball were classified according to the frequency characteristics on the equal loudness contours. Sound quality metrics such as Zwicker's loudness, sharpness, roughness of each classified impact sound were also measured. Loudness spectrum has been regarded as an indication of the characteristics difference of each classified impact sound. The adjectives in Korean expressing the sound quality characteristics of floor impact sounds were also investigated by adoptability and similarity tests. The group of the adjectives was used to evaluate the sound quality of floor impact sound by semantic differential test method.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.997-1002
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• 2004

Rumbling sound is one of the most important interior sound of a passenger car. The conventional rumbling noise research was focused on the reduction of the A-weighted sound pressure level. However A-weighted sound pressure level can not give the whole story about the rumbling sound of a passenger car. In this paper, we employed sound metric which is the subjective parameter used in psycoacoustics. According to recent research results, the relation between sound metrics and subjective evaluation is very complex and has nonlinear characteristics. In order to estimate this nonlinear relationship, artificial neural network theory has been applied to derivation of sound quality index for rumbling sound of a passenger car.

• Fibers and Polymers
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• 제7권4호
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• pp.450-456
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• 2006

The objectives of this study were to investigate physiological and psychological responses to the rustling sound of Korean traditional silk fabrics and to figure out objective measurements such as sound parameters and mechanical properties determining the human responses. Five different traditional silk fabrics were selected by cluster analysis and their sound characteristics were observed in terms of FFT spectra and some calculated sound parameters including level pressure of total sound (LPT), Zwicker's psychoacoustic parameters - loudness(Z), sharpness(Z), roughness(Z), and fluctuation strength(Z), and sound color factors such as ${\Delta}L\;and\;{\Delta}f$. As physiological signals, the ratio of low frequency to high frequency (LF/HF) from the power spectrum of heart rate variability, pulse volume (PV), heart rate (HR), and skin conductance level (SCL) evoked by the fabric sounds were measured from thirty participants. Also, seven aspects of psychological state including softness, loudness, sharpness, roughness, clearness, highness, and pleasantness were evaluated when each sound was presented. The traditional silk fabric sounds were likely to be felt as soft and pleasant rather than clear and high, which seemed to evoke less change of both LF/HF and SCL indicating a negative sensation than other fabrics previously reported. As fluctuation strength(Z) were higher and bending rigidity (B) values lower, the fabrics tended to be perceived as sounding softer, which resulted in increase of PV changes. The higher LPT was concerned with higher rating for subjective loudness so that HR was more increased. Also, compression linearity (LC) affected subjective pleasantness positively, which caused less changes of HR. Therefore, we concluded that such objective measurements as LPT, fluctuation strength(Z), bending rigidity (B), and compression linearity (LC) were significant factors affecting physiological and psychological responses to the sounds of Korean traditional silk fabrics.

• 한국소음진동공학회논문집
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• 제19권11호
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• pp.1202-1213
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• 2009

Muffler sound quality of a vehicle has widely been evaluated using commercial softwares. However, the commercial softwares are providing only simple sound quality index. To get better sound quality evaluation method of the muffler, a new approach is suggested based on the subjective sound quality test. The suggested subjective sound quality evaluation method is refined with the fuzzy theory. The developed method is applied for the evaluation of various kinds of vehicle muffler sounds.