• Title, Summary, Keyword: Sound characteristics

Search Result 1,777, Processing Time 0.039 seconds

Modeling of the Head-Related Transfer Functions with Optimum Reflection Wave Transfer Characteristics in Free-Field Listening over Headphones (헤드폰을 이용한 자유 음장 청취에서의 최적 반사 음파 전달 특성을 갖는 머리 전달 함수 모델링)

  • Yim, Jeong-Bin;Kim, Chun-Duck;Kang, Seong-Hoon
    • The Journal of the Acoustical Society of Korea
    • /
    • v.16 no.2
    • /
    • pp.16-25
    • /
    • 1997
  • A new method to model the HRTF's(Head-Related Transfer Function), which could give improvement of the sound localization accuracy using the spatial effects by the reflected sound wave transfer characteristics, is proposed. When using the HRTF model having reflected sound wave transfer characteristics, the accuracy of sound localization was quite improved up to about 23%, compared with using the direct wave transfer characteristics only. Furthermore, it is verified that the spatial impression could be a factor to enhance the ability of sound localization.

  • PDF

Characteristics of Sound Response in Ear Canal of Human and Reproduction of Acoustical Space (인간 이도의 소리응답특성과 음향공간의 재현)

  • Ahn, Tae-Soo;Lee, Doo-Ho
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.21 no.9
    • /
    • pp.842-849
    • /
    • 2011
  • The human ear canal amplifies the sound pressure level at specific frequency bands. The characteristics of the ear canal are very similar to those of curved cylindrical tube. In this study, the characteristics of sound transfer in human ear canal were measured and the acoustical space of ear canal was reproduced from the canal cavity geometry. For the measurement of sound transfer function in ear canal, a probe microphone and a reference microphone were used. The sound transfer functions were measured for 5 human subjects. To reproduce the acoustical space of the ear canal, two kinds of ear simulator were designed. The first one is a straight cylindrical tube type and the other is a real-shape ear of which geometry was taken from a micro-CT scanning of a human ear. The characteristics of the reproduced apparatus were compared with those of the human and a commercial ear simulator, RA0045 of G.R.A.S. Inc. The comparison results show that the developed apparatus well represent the ear canal characteristics in the low frequency, but have limited coincidence in level over high frequency range.

Development and Application of Measuring Method for Instantaneous Intensity (순시 인텐시티 측정 기법의 개발 및 응용)

  • 이장우;안병하
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • /
    • pp.960-963
    • /
    • 2003
  • Sound intensity method is well known as a visualization technique of sound field and sound propagation in noise control. Sound intensity is a vector quantity that describes the magnitude and the direction of net flow of acoustic energy at a given position. The current measuring method is expensive and difficult to identify the noise source exactly. In this paper, we have studied the noise source identification and the characteristics of noise source of rotary compressor for air conditioner using complex sound intensity method. The new method for instantaneous sound intensity is also proposed and it is useful for transient state and steady state. The criteria of these state, select auto correlation coefficient. The advantage, simplicity and economic attribution of this method are verified by analyzing the characteristics of noise source with instantaneous sound intensity compared to mean sound intensity.

  • PDF

Development and Application of Measuring Method of Instantaneous Intensity (순시 인텐시티 측정 기법의 개발 및 응용)

  • 이장우;김영종;안병하;이운섭
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • /
    • pp.560-563
    • /
    • 1997
  • Sound intensity method is well known as a visualization technique of sound field and sound propagation in noise control. Sound intensity is a vector quantity that describes the magnitude and the direction of net flow of acoustic energy at a given position. The current measuring method is expensive and difficult to identify the noise source exactly. In this paper, we have studied the noise source identification and the characteristics of noise source of rotary compressor for air conditioner using complex sound intensity method. The new method for instantaneous sound intensity is also proposed and it is useful for transient state and steady state. The criteria of these states select auto correlation coefficient. The advantage, simplicity and economic attribution of this method are verified by analyzing the characteristics of noise source with instantaneous sound intensity compared to mean sound intensity.

  • PDF

Sound Power Evaluation of Various Domestic Railroad Vehicles (국내 철도 차량의 음향발생 특성에 대한 비교 연구)

  • Kim, Jeung-Tae;Cho, Sung-Ho
    • Journal of the Korean Society for Railway
    • /
    • v.2 no.1
    • /
    • pp.28-37
    • /
    • 1999
  • Many residential areas are situated near to railroad tracks so that a railroad noise has been one of the major environmental issues. In this paper two important aspects have been investigated in order to properly evaluate the railroad vehicle noise : sound power levels for different types and sound propagation characteristics of the railroad vehicles. For noise source characteristics of railroad vehicles, sound power values for various types of trains that are in active service have been measured. In this paper, domestic railroad vehicles are measured and compared with high speed train(TGV). Based on sound power information of railway vehicles, prediction on the sound pressure level and equivalent noise level near to railway areas have been evaluated.

  • PDF

A Simulation for the Characteristics of the Sound-Pipe of King Song-Dok Bell (시뮬레이션에 의한 성덕대왕 신종 음관의 특성)

  • Choi Myung-Jin;Park Hong-Eul
    • Journal of the Korea Society for Simulation
    • /
    • v.14 no.4
    • /
    • pp.69-76
    • /
    • 2005
  • To investigate the characteristics of the sound-pipe on the top of King Song-Dok bell, using computer simulation, the throat impedance was evaluated for the straight pipe and conical pipes with varying taper angles. When sound propagates in a rigid walled, unflanged circular pipe with wavelength larger than radius, the acoustic motion is planar, much as in a bar. The incident sound waves are reflected at the end of pipe and some of them are transmitted. The reflection coefficient and radiation impedance of the sound-pipe of King Song-Dok bell were calculated, and the results demonstrated that the high frequency sound is radiated through the sound-pipe. It behaves like a frequency filter.

  • PDF

Effects of the sound field characteristics of the receiving room on heavy-weight impact sound measurement generated by impact ball (임팩트 볼에 의한 중량충격음 측정에 있어서 수음실 음장특성의 영향)

  • Yoo, Seung-Yup;Lee, Sin-Young;Jeong, Young;Jeon, Jin-Yong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • /
    • pp.622-625
    • /
    • 2006
  • This study is a fundamental investigation for standardization of the heavy-weight floor impact measuring method by the impact ball. The distribution chrematistics of floor impact sound level and reverberation time in a receiving room of the testing building for floor impact sound were measured with variations of number and arrangement of the sound-absorbing materials. Total 8 cases were investigated. The distribution of the floor impact sound level($L_{i,\;Fmax}$) was measured at 30 points with same intervals. The absorption coefficient of the room is 0.10 in case of installation of 6 absorbing materials and 0.02 in case of non-installation. The distribution shape of the impact sound pressure level was similar to the result of the bang machine driving at the measured frequency range. However, the overall reduction of the impact sound level investigated in the 125 to 500 Hz shows that the sound absorption characteristics of the receiving room actually affects the result of the heavy-weight impact measurement.

  • PDF

Analysis of Heart Sound Using the Wavelet Transform (Wavelet Transform을 이용한 Heart Sound Analysis)

  • 위지영;김중규
    • Proceedings of the IEEK Conference
    • /
    • /
    • pp.959-962
    • /
    • 2000
  • A heart sound algorithm, which separates the heart sound signal into four parts; the first heart sound, the systolic period, the second heart sound, and the diastolic period has been developed. The algorithm uses discrete intensity envelopes of approximations of the wavelet transform analysis method to the phonocard-iogram(PCG)signal. Heart sound a highly nonstation-ary signal, so in the analysis of heart sound, it is important to study the frequency and time information. Further more, Wavelet Transform provides more features and characteristics of the PCG signal that will help physician to obtain qualitative and quantitative measurements of the heart sound.

  • PDF

An Experimental Study on the Prediction of Indoor Sound Level Distribution in Apartment for Exterior Noise (외부소음에 대한 공동주택 실내 소음레벨분포에 관한 실험적 연구)

  • Park, Hyeon-Ku;Kim, Jong-Bin;Kang, Dong-Yong;Jang, Hyun-Choong;Song, Hyuk;Kim, Sun-Woo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • /
    • pp.259-264
    • /
    • 2001
  • It is necessary to predict the sound pressure level(SPL) in rooms before designing an apartment when exterior noises are produced. In order to predict SPL for an apartment that has some specific exterior noises, the following should be known: the characteristics of outdoor noise, sound insulation performance and sound level differences of each room. The purpose of this study is to find out the possibility of predicting sound pressure level of rooms in an apartment by analysing sound level differences among rooms. Sound sources used in this experiment are construction noise, aircraft noise, railroad noise, road traffic noise and white noise as a reference to compare with the previous four. These noises were recorded and reproduced by speaker. As a result, we found that within the sound reduction pattern, the sound difference level appeared uniform depending on the sound insulation characteristics of the windows installed when facing the noise source. When the windows having the same acoustic performance were installed, the SPL in each room resulted in nearly the same values.

  • PDF

Absorption Characteristics of Sound Proof Wall by Scrap Aluminum and Perforated Plate (알루미늄칩과 타공판을 이용한 방음벽 충진재의 흡음특성)

  • Lee, Young-Jung;Kim, Dae-Gun;Park, Kyung-Hwa;Kim, Young-Do
    • Korean Journal of Materials Research
    • /
    • v.19 no.7
    • /
    • pp.382-385
    • /
    • 2009
  • Efforts to reduce noise in industrial application fields, such as automobiles, aircrafts, and plants have been gaining considerable attention while a sound proof wall to protect people from the noise has been intensively investigated by many researchers. In this study, our research group suggested creating a new sound proof wall composed of scrap aluminum chips and perforated plates in a commercial polyester sound proof wall, which was then successfully fabricated. This wall's sound absorption characteristics were measured by an impedance tube method. The sound absorption property was evaluated by measuring the Noise Reduction Coefficient (NRC) to the standard, ASTM C 423-90a. The noise reduction coefficient of the sound proof wall composed of 3.5 vol.% and 7.5 vol.% of scrap aluminum chips relatively increased to 5% and 8% compared to the commercial polyester sound proof wall. The scrap aluminum perforated plate also relatively increased to 13% compared to the commercial polyester sound proof wall.