• Electronics and Telecommunications Trends
• /
• v.6 no.3
• /
• pp.101-109
• /
• 1991

전화통화시, 송화측음에 따른 송화자의 음성레벨의 변화와 송화시 전화기를 통한 실내소음에 따른 음성레벨의 변화에 대해 알아보았다. 그 결과, 송화자는 항상 자신의 귀로 되돌아 오는 음성의 심리적 크기를 일정하게 유지하려는 모니터 기능을 보여, 측음의 크기와 송화시 실내소음의 크기에 따라 자신의 음성레벨을 제어하는 경향을 보였다.

• The Journal of the Acoustical Society of Korea
• /
• v.11 no.1
• /
• pp.52-59
• /
• 1992

In order to see the effects of talker sidetone on a talker's speech level quantitatively when he converses with others on a telephone, we reviewed the measuring algorithm of speech level and assessed variation of speech level due to that of sidetone masking rating(STMR). We measured room noise effects on speech level, when STMR values were changed, as well. If we consider the effects of talker sidetone and room noise on speech level, the results of experiments suggest that a talker continuously tries to keep the psychological loudness of his own speech, heard by himeself via a telephone handset, at the constant and comfortable level by controlling his speaking level according as STMR value and room noise are change. That is, because the amount of his speech masked by his talker sidetone and room noise is different when STMR value and room noise are changed, we can see the tendency that he controls his speaking level in order to keep the perceived psychological loudness of his own speech to be constant.

• The Journal of the Acoustical Society of Korea
• /
• v.43 no.5
• /
• pp.517-528
• /
• 2024

This paper reports the results of a recent acoustic survey conducted with the objective of providing on the acoustic conditions of school classrooms in Korea. The measurements included both occupied speech and noise levels during 27 active classes and unoccupied data on the acoustical conditions, and sound insulation performance in 16 classrooms in 4 schools. The effects various parameters on the speech and noise levels in occupied classrooms has been examined. The impact of room acoustic design on speech and noise levels in active classrooms has been also investigated. The speech and noise levels of the elementary school are approximately 4 dBA to 5 dBA higher than those of the other three schools (junior high, high, and special), likely due to the nature of activities involved in group work and the age of the students. A notable 19 dBA difference is observed between the quietest and noisiest classroom activities and the classrooms in which students were observed working in groups with discussion had the highest noise levels. Both occupied and unoccupied data have enabled the establishment of a comprehensive picture of the acoustic conditions in classrooms and have highlighted the necessity of introducing acoustic standards for improving the acoustic environment in Korean schools.

• The Journal of the Acoustical Society of Korea
• /
• v.37 no.5
• /
• pp.369-377
• /
• 2018

This study investigated the effect of noise and reverberation on subjective measure of speech transmission performance for elderly person with hearing loss in residential space through listening test. Floor impact, road traffic, airborne, and drainage noise were employed as the residential noise, and several impulse responses were obtained through room acoustical computer simulation for an apartment building. Sound sources for the listening test consisted of residential noises and speech sounds for boh the young (the original sound) and the aged (the sound filtered out by filters with frequency responses of hearing loss of 65 years elderly person). In the listening test, subjects evaluated speech intelligibility and listening difficulty for the presented word ($L_{Aeq}$ 55 dB) at three noise levels ($L_{Aeq}$ 30, 40, 50 dB) and three reverberation times (0.5, 1.0, 1.5 s). Results showed that the residential space with noise level lower than equal to 50 dB ($L_{i,Fmax,AW}$) for jumping noise and 40 dB ($L_{Aeq}$) for road traffic, airborne, and drainage noise had speech intelligibility of 90 % and over and listening difficulty of 30 % and below. Speech intelligibility and listening difficulty for the aged sound source was shown to be 0 % ~ 5 % lower and 2 % ~ 20 % higher than those for the young sound source, respectively.

• Fire Protection Technology
• /
• s.42
• /
• pp.17-25
• /
• 2007

쾌적하고 명료성이 높은 교실내의 음향환경은 학생들의 학업 성취도 및 교사의 언어전달 이해 향상을 이룩할 수 있는 중요한 사항이다. 이러한 우수한 교육환경을 위해서는 우선 우리나라의 교실 음향 실태 파악과 함께 교육시설의 음향상태 및 소음에 의한 학업 성취도, 심리적, 사회적 영향에 대한 정량적 조사가 이루어 져야 한다. 국내 교육시설의 음향 실태 파악을 통해 교육시설에서의 음향 및 소음 기준을 수립하여 교육시설내의 음환경 개선을 추진해야 한다. 교실 음향개선을 합리적으로 평가할 수 있는 지표로서 잔향시간과 배경소음이 가장 중요한 요소로 알려져 있다. 교실의 우수한 음환경을 위해 적절한 잔향시간은 $0.4\sim0.6$초, 배경소음은 NC-$25\sim30$수준이 확보되어야 하는 것으로 조사되었다. 또한 교사의 음성레벨과 배경소음과의 비(S/N비)는 최소 10 dB이상 되어야 강의 내용 전달이 가능하며, 각종 기계설비에서 발생되는 소음 및 진동은 저소음 기기 선정을 통해 최소화하여야 한다. 인접 실에서 발생되는 소음을 충분히 차단하기 위해서는 차음성능 우수한 구조의 벽계로 개선되어야 하며, 기밀성이 높은 출입문사용과 적절한 출입구 배치를 통해 인접한 교실로의 소음 전달을 최소화 할 수 있다.

• Proceedings of the Acoustical Society of Korea Conference
• /
• 1996.06a
• /
• pp.1-3
• /
• 1996

수중 트랜스듀서는 진동하는 물체위에 설치되어 다양한 외부 소음원이 유입되는 환경에 노출되어 있다. 외부 소음원으로는 선체 진동. 프로펠러 소음, 그리고 유동 유기 소음들을 들 수 있고, 트랜스듀서의 실제 작동시 이들의 레벨이 상당히 높아서 센서의 정확한 작동에 장애가 되고 있다. 본 논문에서는 외부 소음원에 무관한 고 정밀, 저 소음 특성을 지닌 음향센서를 개발하기 위하여 유한요소법 (FEN)을 사용하여 소음 전달 특성을 분석하고, air pocket과 음향 감쇠층의 다양한 조합으로 이루어진 구조를 개선한 음향센서의 설계 및 내소음성 평가를 하였다. 또한 사용한 음향 감쇠층의 최적 물성을 제시하고자 한다. 그 결과 센서 측면 하단부에 소음원이 위치할 경우 가장 큰 잡음 신호로 작용하며, 구조를 변경한 결과 기존 음향센서에 비해 55% 이상 내 소음성을 증진 시켰다. 그리고 음향 감쇠층의 최적 음향 임피던슨는 1 Mrayl 이하 혹은 4mrayl 이상으로 분석되었다.

• The Journal of the Acoustical Society of Korea
• /
• v.42 no.2
• /
• pp.113-123
• /
• 2023

This paper describes the acoustical conditions of elementary school and high school classrooms as well as university classrooms in Korea and suggests a need for Korean acoustic standards and guidelines for classroom design. Current standards and guidelines of classroom acoustics in several countries were briefly introduced to understand their acoustical performance criteria for background noise levels and reverberation times, and noise isolation design requirements in various types of classrooms. The results of several acoustic survey of domestic classrooms in elementary school, high school, and university were described and compared to provide information of the acoustic characteristics of Korean school classrooms. The survey includes occupied and unoccupied data on the acoustical conditions, noise levels, and noise isolation performance in the classrooms. Acoustical parameter values for achieving 'good' speech intelligibility in active university classrooms were also presented.

• The Journal of the Acoustical Society of Korea
• /
• v.42 no.4
• /
• pp.285-297
• /
• 2023

The present study aims to investigate the acoustic performance of the creative convergence classrooms in Korea used by elementary school students under the age of 9 introduced through the school space innovation project. In order to do this, acoustic performances of three creative convergence classrooms were measured. The measured acoustic parameters were background noise levels, Reverberation Time (RT), D₅₀, Speech Transmission Index (STI), and Inter-Aural Cross Correlation (IACC). Also, acoustic parameters including Transmission Loss (TL) and standardized level difference (D_nT) have been measured for the analysis of sound insulation performance of walls. In addition, the noise level was measured according to the opening conditions of doors and windows in the classroom. As a result, background noise level was measured at an average of 28.0 dB(A) to 32.8 dB(A) when the air conditioner was not operated, and the RT did not exceed 0.6 s. There were differences in IACC according to various desk layouts, and IACC values were high in the center line and the seats near the sound source. In particular, higher IACC was measured at the seats on the center line facing the source squarely. Regarding noise level in the classroom according to the opening conditions of doors and windows, the standards were exceeded when all windows, or windows and doors front onto the corridor were opened.

• The Journal of the Acoustical Society of Korea
• /
• v.36 no.5
• /
• pp.329-337
• /
• 2017

In USA and UK, the standards of both reverberation time and background noise level have been established for the appropriate aural environment in classrooms. In order to realize this, guidelines for architectural planning and interior finishing have been also suggested. However, in Korea, there has hardly been any guidelines for satisfying background noise criteria and investigation about sound insulation performance of current walls of classrooms. The present study investigates the structure of outer wall and walls between classrooms of two middle schools in order to analyze the sound insulation performance against both exterior and interior noises. Acoustic parameters including transmission loss, standardized sound level difference, and signal to noise ratio have been measured and analyzed for sound insulation performance of walls and flanking noises. As a result, concerning the walls in between classrooms, it was found that walls of dry construction have greater sound insulation performance rather than the walls of wet construction especially in mid and high frequency bands. Also, It was revealed that thermopane, insulated pair glass, of outer walls, has greater sound insulation performance than the double window consisted of two single pane glass. Regarding flanking noises, the standards were exceeded when all windows, or windows and doors front onto corridor were opened. It denotes that students could be disturbed with the sound transmission by the interior noises.