• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.4
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• pp.289-298
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• 2014

Pass-by noises of various trains were recorded by binaural recorder. The measured noises were evaluated using a sound pressure level and psychoacoustic metrics objectively. To analyze a binaural effect on annoyance that can be caused by train noise, auditory experiments were performed. Through the experiments, the annoyance differences between monaural and binaural train noises, the annoyance differences due to measurement angle and the annoyance differences due to kinds of train and measurement distance were determined. A correlation analysis was conducted to determine which index can affect the annoyance more strongly. As the result, a maximum rate of change of sharpness difference between left and right channels was proposed to predict the annoyance.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2014.11a
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• pp.154-155
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• 2014

본 논문에서는 TV 시청환경에서의 실내소음의 스트레스 평가를 위한 소음 데이터베이스(database, DB) 설계 방법을 제안한다. 제안된 DB 는 TV 시청공간을 포함하는 실제 주거환경 내에서 binaural recording을 위한 1 개의 dummy head 와 multi-channel recording 을 위한 2 개의 다채널 마이크 배열을 활용하여 TV 콘텐츠 및 실내소음의 음향 정보를 취득한다. 설계된 DB는 TV 시청자의 청각정보에 해당하는 binaural recording 신호와 실내소음의 위치 및 종류 추정을 위한 multi-channel recording 신호를 모두 포함하기 때문에 TV 시청환경에서 실내소음이 시청자에게 유발하는 스트레스의 분석 및 평가 관련 연구에 적합하게 설계되었다. 본 DB 는 5 가지 종류의 TV 콘텐츠 10 시간 분량, 30 가지 종류의 실내소음 2 시간 분량으로 구성되었다.

• ETRI Journal
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• v.22 no.2
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• pp.11-19
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• 2000

If the right and left signals of a binaural sound recording are reproduced through loudspeakers instead of a headphone, they are inevitably mixed during their transmission to the ears of the listener. This degrades the desired realism in the sound reproduction system, which is commonly called 'cross-talk.' A 'cross-talk canceler' that filters binaural signals before they are sent to the sound sources is needed to prevent cross-talk. A cross-talk canceler equalizes the resulting sound around the listener's ears as if the original binaural signal sound is reproduced next to the ears of listener. A cross-talk canceler is also a solution to the problem-how binaural sound is distributed to more than 2 channels that drive sound sources. This paper presents an effective way of building a cross-talk canceler in which geometric information, including locations of the listener and multiple loudspeakers, is divided into angular information and distance information. The presented method makes a database in an off-line way using an adaptive filtering technique and Head Related Transfer Functions. Though the database is mainly concerned about the situation where loudspeakers are located on a standard radius from the listener, it can be used for general radius cases after a distance compensation process, which requires a small amount of computation. Issues related to inverting a system to build a cross-talk canceler are discussed and numerical results explaining the preferred configuration of a sound reproduction system for stereo loudspeakers are presented.

• The Journal of the Acoustical Society of Korea
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• v.38 no.6
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• pp.637-650
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• 2019

This paper analyzes the limitations of binaural sound that is reproduced with headphones based on Ambisonics for Virtual Reality (VR) audio. VR audio can be provided with binaural sound that compensates head rotation of a listener. Ambisonics is widely used for recording and reproducing ambient sound fields around a listener in VR audio, and the First order Ambisonics (FOA) is still being used for VR audio because of its simplicity. However, the maximum frequencies with this order is too low to perfectly reproduce ear signals, and thus the binaural reproduction has inherent limitations in terms of spectrum and sound localization. This paper investigates these limitations by comparing the signals arrived at ear positions in the reference field and the reproduced field. An incidence wave is defined as a reference field, and reproduced over virtual loudspeakers. Frequency responses, inter-aural level differences, and inter-aural phase differences are compared. The results show, above the maximum cut off frequency in general, that the reproduced levels decrease, and the horizontal localization can be provided only around the forward direction.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.215-218
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• 2000

입체음향 생성을 위한 기존의 방법은 크게 바이노럴 녹음기법과 머리전달함수(HRTF)를 이용한 바이노럴 합성 기법으로 나눌 수 있다. 현재 바이노럴 기법은 기존 스테레오 시스템에 비해 공간감, 몰입감 측면에서는 탁월한 효과가 있지만, 음질의 저하와 정면 음상 정위가 잘되지 않는다는 치명적인 단점 때문에 프로페셔널 오디오 분야에서는 거의 사용되지 않고 몇몇 PC 게임용으로만 사용되고 있다. 본 논문은 정확한 정면 음상 정위를 위해 '3채널 더미헤드를 이용한 바이노럴 녹음기법' 을 제안하고, 기존 스테레오 녹음기법과의 호환성 유지를 위해 녹음 현장에서 직접 사용될 수 있는 3채널 더미헤드를 사용한 'Weighted Diffuse-field equalization 기법'에 대해 제안하며, 3 채널 더미헤드를 이용하여 기존 HRTF 데이터를 대체할 수 있는 정면 음상 정위에 강인한 '3 채널 더미헤드 HRTF 측정 기법'에 대해 제안한다.

• The Journal of the Acoustical Society of Korea
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• v.32 no.4
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• pp.335-345
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• 2013

The present study investigates the effect of the inter-aural level difference(ILD) on the syllable articulation test in classrooms which can be occurred by the absorption of interior surfaces. In order to do this, the sound absorbing materials were installed in the classroom and sound pressure level(SPL) at each ear was measured using binaural recording systems. Also, syllable articulation tests were carried out at a classroom with and without sound absorption materials by 20 students who have normal hearing condition, in order to investigates the effect of the ILD on the speech intelligibility. As a result, it was found that the larger inter-aural level differences was occurred at the nearer positions to lateral walls after sound absorptions were applied to lateral walls in the classroom. At some places, the measured ILD was lager than JND of sound level (3dB). Also, it was shown that the correlation coefficient of inter-aural level difference with the score of syllable test has the significant result(-0.441). Thus, It is concluded that ILD can affect the subjective speech intelligibility in classrooms.