• Journal of the Korea Society of Computer and Information
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• v.22 no.7
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• pp.83-91
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• 2017

In this paper, we propose a thorough solution for adjusting virtual sound field with different kinds of devices and software in preliminary procedure and late stage of music processing. The basic process of music production includes composing, arranging and recording at pre-production stage as well as sound mixing and mastering at post-production stage. At the initial stage of music creation, it should be checked whether the design of virtual sound field, the choice of the tone and the instrument used in the arrangement match the virtual sound field required for the final work. In later recording, mixing and mastering, elaborate adjustments should be done to the virtual sound field. This study also analyzed how to apply the parameter of the effectors to the design and adjustment of the virtual sound field, making it the source of our creation.

• Korean Journal of Environment and Ecology
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• v.29 no.2
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• pp.174-183
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• 2015

We have conducted a verification test of correlation between bird community indices and bird sound recording results in order to use the equipment which deals with the automatic sound collecting system, the song meter. The study areas include four sites which are Gombaeryoung and Zochimryoung in Jeombongsan Mountain and Jookryoung and Gochiryoung in Sobaeksan National Park. We collected the bird sound data five times using a sound recorder and field survey results in the same place of the study site. As a result of the sound recording from the field survey, the species recorded by three researchers of sound analyst include common resident species or species which have a relatively conspicuous call and song. On the contrary, the species recorded by only one researcher are a relatively rare or inconspicuous species or was familiar with the personal experiences of each researcher. The number of species recorded by only one researcher totaled fourteen species (36.8 %), and that of two researchers totaled twelve species (31.6 %), and that of three researchers totaled twelve species (31.6 %). The correlations of the number of species among three researchers was not significant in some results, but the sum or maximum count of the number of species was useful to estimate a significant correlation between the result of researchers and the indices of field surveys. As a result of correlation analysis by using sound recordings, the maximum number of species among the three researchers significantly correlated with the number of species, the species diversity index and the species abundance index in the field survey at the same site, however it did not correlate with the number of individuals and species evenness index. As a result of sound analysis collected from the stationary sound recording system; song meter, the number of frequencies in bird songs and calls correlated with the number of species in the field survey at the same site. The number of calls and songs decreased as time went by. Finally, we could test the active time range and change the activity strength by using a sound recording system. In particular, that sound recording system is able to collect data in same time and site, so it is expected so that the equipment not only replenish a shortage of researchers and survey periods in field research in a short term monitoring survey, but also be able to acquire statistical objectivity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05b
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• pp.96-102
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• 2003

Today, stage technology is developing highly by application of digital computer. Performance is composed of audio/video and acoustic technology takes very important position in field of stage technology. Generally speaking, four factors of sound are loudness, pitch, sound timbre and duration. Loudness depends on sound pressure level, yet partly related with spectrum and dulation. Pitch depends mainly on frequence and have a relation with sound pressure and duration. sound timbre depends strongly on spectrum and have a relation with frequence. In this paper, I designed a multi-microphone system which can used in broadcasting and performance stage with vicboss 200MHz-VHF wireless microphone and vicboss 900MHz-VHF wireless microphone. I also studied about multi-microphone which can use conveniently in the super play that needs many microphones. If this multi-microphone is prodused, we could expect better sound quality and a big progress in stereo recording technology.

• Korean Journal of Environment and Ecology
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• v.32 no.1
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• pp.39-46
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• 2018

Breeding bird surveys provide the reference information for understanding bird community structure and function in the ecosystem and conserving biodiversity. Recent rapid change of biodiversity due to climate change and other factors has made it necessary to utilize acoustic sensors for accuracy and spatial expansion of forest bird survey data and for time-series monitoring of forest birds. The objective of this study is to investigate the possibility of using acoustic recording sensor to evaluate the diversity of forest birds at breeding season by comparing and analyzing the recorded data of bird songs and field bird survey data. We conducted the site survey and recording in 186 points in 48 areas of 4 regions of Gombaeryeong and Jochimryeong around Jeombongsan Mountain and Jugryeong and Gochiryeong around Sobaeksan Mountain from May 2nd to 16th in 2013. The analysis of the correlation between the recording result and Bird Community Index based on the field survey showed that the number of bird species, population, and the number of bird songs by recording was significantly correlated to the number of species and population by field survey. Moreover, the number of bird species and the number of bird songs by recording showed a significant correlation to species diversity and species richness but no or low significant correlation to species evenness by the field study (observation and listing in parallel). As a result, it was possible to check species composition and species diversity of bird communities by analyzing acoustic recording data on the field. The acoustic recordings of bird songs in the breeding period were more reliable than the non-breeding period in the correlation of recording result and species diversity and for utilization.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.451-462
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• 2003

At the paper the method of 3D holographic moving image reconstruction is discused. The main idea of this method is based on the substitution of optically created static hologram by equal diffraction array created by acoustical (AO) field which formed by bulk sound waves. Such sound field can be considered as dynamic optical hologram, which is electrically controlled. At the certain moment of time when the whole hologram already formed, the reference optical beam illuminates it, and due to acoustooptical interaction the original optical image is reconstructed. As the acoustically created dynamic optical hologram is electronically controlled, it can be used for moving 3-dimentional scene reconstruction in real time. The architecture of holographic display for moving scene reconstruction is presented at this paper. The calculated variant of such display laboratory model is. given and discussed. The mathematical simulation of step by step images recording and reconstruction is given. The pictures of calculated reconstructed images are presented. The prospects, application areas, shortcomings and main problems are discussed.

• Journal of Information Display
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• v.4 no.3
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• pp.29-34
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• 2003

At the paper the method of 3D holographic moving image reconstruction is discused. The main idea of this method is based on the substitution of optically created static hologram by equal diffraction array created by acoustical (AO) field which formed by bulk sound waves. Such sound field can be considered as dynamic optical hologram, which is electrically controlled. At the certain moment of time when the whole hologram already formed, the reference optical beam illuminates it, and due to acoustooptical interaction the original optical image is reconstructed. As the acoustically created dynamic optical hologram is electronically controlled, it can be used for moving 3-dimentional scene reconstruction in real time. The architecture of holographic display for moving scene reconstruction is presented at this paper. The calculated variant of such display laboratory model is given and discussed. The mathematical simulation of step by step images recording and reconstruction is given. The pictures of calculated reconstructed images are presented. The prospects, application areas, shortcomings and main problems are discussed.

• The Journal of the Acoustical Society of Korea
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• v.30 no.8
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• pp.410-420
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• 2011

The present study aims to investigate the soundscapes of Jeju olle route through the soundwalking. In order to do this, sound measurements and sound recording were undertaken at 10 points along Jeju olle route. Also, loudness of background sound and figure sound were examined. Subjective surveys were carried out using questionnaire and interviews with 32 tourists and 5 acoustical specialists in order to investigate the loudest sound, most pleasant and unpleasant sound, and impressive sound among 17 natural and artificial sounds. Additionally, laboratory experiments were achieved to evaluates sound that have been recorded at the field using same questionnaire and the results were compared with those of field experiments. As a result, the sound heard most in Jeju olle route is the sea wave sound, wind sound, automobile noise, and human voice. It was revealed that the most pleasant sound consisted of nature sound among them, and that unpleasant sounds are artificial sounds. The results of subjective test denote that unpleasant sound is affected by ratio of artificial sound and nature sound. And this also affects the assessment about the loudness of the sound. Also, it was found that the results of both field test and laboratory test are closely correlated in the evaluation of loudness of sound and unpleasant feeling.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.25 no.1
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• pp.12-17
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• 1989

A field experiment was carried out of confirm the effect of underwater sound on the luring of fish school of chub mackerel in the coast of Idousyo Island. Underwater sound that was made use of luring of fish school was pure sound and interval pure sound which the frequencies of the sound were 150Hz and 200Hz, respectively. The results of the observation of hooking and recording paper of fish finder indicate that the effect of emitting sound at 20m in the depth of water was remarkable for the luring of fish school of chub mackerel. The vertical pure sound pressure level at 150Hz and 200Hz of the water layer that was lured the fish school of chub mackerel were 140.1dB and 146.dB at 30m, 121.0dB and 126.6dB at 70m and 141.9dB and 120.5dB at 120m in the depth of water, respectively.

• 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.

• The Journal of the Acoustical Society of Korea
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• v.41 no.3
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• pp.287-301
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• 2022

The present study aims to investigate the difference of soundscape evaluation results from on-site field test and laboratory test which are commonly used for soundscape surveys. In order to do this, both field and lab tests were carried out at four different areas in Cheongju city. On-site questionnaire surveys were undertaken to 65 people at 13 points. Laboratory listening tests were carried out to 48 adults using recorded sounds and video. Laboratory tests were undertaken to two different groups who had experience of field survey or not. Also, two different sound reproduction tools, headphones and speakers, were used in laboratory tests. As a result, it was found that there is a very close correlation between sound loudness and annoyance in both field and laboratory tests. However, it was concluded that there must be a difference in recognizing the figure sounds between field and laboratory tests since it is hard to apprehend on-site situation only using visual and aural information provided in laboratory tests. In laboratory tests, it was shown that there is a some difference in perceived most loud figure sounds in two groups using headphones and speakers. Also, it was analyzed that there is a tendency that field experienced people recognize the figure sounds using their experienced memory while non-experienced people can not perceive the figure sounds.