중량 바닥충격음 측정의 신뢰성 향상을 위한 측정방법 검토

주문기,박종영,양관섭,오양기,Joo, Moon-Ki,Park, Jong-Young,Yang, Kwan-Seop,Oh, Yang-Ki 한국음향학회 2008 韓國音響學會誌 Vol.27 No.4

대부분의 바닥충격음측정은 반사성 재질로 마감된, 가구도 커튼도 없는 수 미터 치수의 장방형 공실에서 이루어진다. 이러한 공간에서 저주파 모드의 발생을 피하는 일은 쉽지 않다. 현재의 측정표준에 따른 중량 바닥충격음 측정의 재현성과 신뢰성을 저해하는 가장 큰 요인은 이러한 저주파 모드 중첩 현상이며, 그 측정의 편차는 63Hz 대역에서 때론 10dB에 이르는 경우도 있다. 이 연구에서는 중량바닥충격음 측정의 편차원인인 저주파 대역 모드중첩의 영향을 줄일 수 있는 보다 신뢰성 있는 측정방법을 찾고자 하였다. 그 방법으로 수음실의 모드 중첩 현상 자체를 제어하는 방법과 어느 정도 모드가 존재하는 상황에서도 수음실 공간 전체의 음압레벨 평균에 가깝게 측정할 수 있는 방법의 두 가지에 대하여 실험하였다. 실험의 결과 저음흡음재 보다 베이스 트랩을 이용하여 수음실의 울림을 줄이는 방식은 수음실의 모드중첩을 제어하는 데는 효과가 있지만 현실적으로 다양한 측정 현장에서 저음 잔향시간을 $1{\sim}2$ 초 사이로 구현하는 일이 쉽지 않음이 단점으로 드러났다. 마이크로폰을 회전시키면서 공간적 평균을 구하는 방식은 측정이 복잡하지도 않으며 쉽게 많은 수음점을 확보하여 수음실 전체 공간을 통한 측정값과 근소한 오차를 보이는 것으로 밝혀졌다. Most of receiving rooms for the measurement of floor impact sound have rectangular shapes with couple of meters of dimension, with reflective finishing, no furniture, no curtains. Modal overlaps in those condition are the major reason for the low reproducibility, and as a matter of course, the low credibility. It is the major purpose of this study that searching for a better measurement method which mitigate the effect of modal overlap on measurement. Two ways of methods are tested. One is the way described in ISO standards which enables controlling the room modes of receiving rooms, the other is the way which enables to get more precise spatial averages in receiving rooms with room modes. It is not easy maintaining the reverberation time of low frequency bands in the range between 1s and 2s, though it is proven to be effective controlling the room modes with base traps. Space-time average SPL's through combinations of rotating microphones are easy to measure, and have good consistencies with average SPL of entire receiving room.

교실내 흡음성능과 스피커 음압레벨에 따른 청취환경 변화

주문기(Joo, Mun-Ki),오양기(Oh, Yang-Ki) 한국건축친환경설비학회 2014 한국건축친환경설비학회 논문집 Vol.8 No.6

It is often the case that various kinds of language listening tests are held in high school classrooms. Absorption material and loudness of speakers are the major variable factor of listening environment in the classroom. The absorption material in the classroom may influence the listening environment. So in this study, acoustical measurements were carried out in the classroom. According to the increase of absorption material and number of speakers, D50 value increases in all receiving point. And 0.1-0.13 D50 value was increased by attach the absorption material at both side wall. As the sound pressure level increased, so did the D50 value in all receiving point. But sound pressure level reach the certain limitation, D50 value was decreased.

소음원에 따른 교실내 청취환경 변화에 관한 연구

주문기(Joo Mun Ki),오양기(Oh Yang Ki) 한국건축친환경설비학회 2012 한국건축친환경설비학회 학술발표대회 논문집 Vol.2012 No.10

It is often the case that various kinds of language listening tests are held in high school classrooms. Noise sources of air conditioner and fan are the major variable factor of listening environment in the classroom. The noise sources occurred in the classroom may influence the listening environment. So in this study, acoustical measurements were carried out in the two different classroom. According to the noise sources, the D50 value had a little change in the low frequency ranges. But these results appear to have little influence on the STI value.

노후 철도 방음벽의 성능에 관한 연구

주문기(Joo, Mun-Ki),고효인(Ko Hyo-In),홍지영(Hong Ji-Young),오양기(Oh Yang-Ki) 한국건축친환경설비학회 2015 한국건축친환경설비학회 논문집 Vol.9 No.3

In recently, numbers of civil appeal about railroad noise are growing due to the deterioration railroad noise barrier walls. The regulation of sound barrier wall used sound absorption coefficient of sound proof panels must apply the average of sound absorption coefficient in four frequency ranges (250,500,1000,2000㎐). In the measurement , the regulation of sound absorption coefficient is satisfactory when the average value of sound absorption coefficient is over 0.7. However after installation of noise barrier wall, it isn"t know whether the performances of noise barrier walls are good or bad because of being not a management regulation of noise barrier wall. So in this study, the measurements of sound absorption coefficient and investigate on the present condition of noise barrier walls were carried out in the field and laboratory. As the results, the number of problem on the noise barrier wall were found out. According to the deterioration, a damaged part and bending problem and crack and deterioration of sound absorption material has appeared in the noise barrier wall. Particularly sound absorption coefficient of over 1㎑ frequency ranges were measured 0.8-0.52. It seemed to be clogged with the dust in the absorption material. So it is expected that the management regulation of railroad noise barrier wall is needed.

학교교실에서 스피커의 위치 및 출력변화에 따른 청취환경 변화에 관한 연구

주문기(Joo, Mun-Ki),오양기(Oh, Yang-Ki) 한국건축친환경설비학회 2011 한국건축친환경설비학회 논문집 Vol.5 No.4

It is often the case that various kinds of language listening tests are held in high school classrooms. The condition of listening environments may influence the test. Currently, high school classrooms have a variety of listening environments. Size of classrooms, location and performance of loudspeakers, doors and windows location which may affect the background noise level, reverberation are the part of the factors which affect the listening environment. Among those conditions, the change of listening environment according to the positions, power and number of speakers are studied in this study. The results show that ceiling four speakers uniformly installed are more narrow deviations in STI value than that of one speakers. And the directivity of speakers are more effective to improve the listening environment than change the speakers power.

노후 아파트의 바닥충격음 및 급ㆍ배수 소음 저감방안에 관한 연구

주문기(Joo, Moon Ki),한명호(Han, Myung Ho),오양기(Oh, Yang Ki) 한국생태환경건축학회 2009 한국생태환경건축학회 논문집 Vol.9 No.2

중량바닥충격음 현장측정의 편차요인에 관한 연구

주문기(Joo Mun-Ki),오양기(Oh Yang-Ki) 한국건축친환경설비학회 2013 한국건축친환경설비학회 논문집 Vol.7 No.4

The new accreditation scheme for the floor impact noise of apartments is announced officially by Ministry of Land, Infrastructure and Transport. According to the new accreditation scheme for the floor impact noise, the accreditation is given by the field measurement in the actual construction site. There is still uncertainty among field measurement results. Measurements were carried out in the same apartment of 19 units to quantify the uncertainty factor. The result shows that there are even 7 dB deviations among the 19 units in the single number rating scheme. Such deviations seems to be from poor quality control in construction stage and room mode due to modal overlap in low frequency ranges. Based on the results, improved measurement method for a better microphones position and increase of sample which would normalize the deviation are proposed.

공동주택의 소음 현황에 관한 실험적 연구

주문기(Joo, Mun-Ki) 한국건축친환경설비학회 2014 한국건축친환경설비학회 논문집 Vol.8 No.6

The noises in apartment houses are important factor that determine the quality of indoor sound environment. Particularly, floor impact noise and plumbing noise and outdoor noise has caused the uncomfortable environment in the apartment houses. So in this study, field measurements of floor impact sound and plumbing noise and outdoor noise were carried out in the apartment house. And the plans to improve the performance of indoor environment were studied. As the results of the measurements, the levels of heavy-impact floor noise and plumbing noise and outdoor noise exceeds the regulations at currently condition. The heavy-impact floor noise level were decreased 15-33dB in higher 125Hz when the floor changes the wet construction method with resilient material. And the plumbing noise and outdoor noise are also expected to decreased as the change of pipe systems and system windows.

방음터널의 길이와 단부처리에 관한 실험적 연구

주문기(Moon-Ki Joo),김태훈(Tae-Hun Kim),오양기(Yang-Ki Oh),김하근(Ha-Gun Kim),이원렬,조성환(Sung-Hwan Cho) 한국소음진동공학회 2003 한국소음진동공학회 학술대회논문집 Vol.2003 No.5

마이크로폰의 위치에 따른 중량 바닥충격음레벨의 편차

오양기,주문기,박종영,김하근,양관섭,Oh Yang-Ki,Joo Moon-Ki,Park Jong-Young,Kim Ha-Geun,Yang Kwan-Seop 한국음향학회 2006 韓國音響學會誌 Vol.25 No.2

현행 중량 바닥충격음 표준 측정방식인 KS F 2810-2에 의하면 중앙점을 포함한 3-5곳의 타격위치에 대하여 수음실에서 4곳 이상의 지점의 피크레벨을 측정하도록 되어있다. 그러나 이 표준 방식에 의한 동일 상황에서의 측정 결과가 측정기관, 측정횟수, 측정점의 위치 등에 따라 일관성을 보이지 못하고 있음이 종종 발견된다. 이러한 편차는 반복성이나 재현성의 측면에서 측정값의 신뢰도에 영향을 미칠 수 있는 수준으로 우려된다. 측정결과 실험실의 경우 중앙 타격시 63Hz 대역에서 각 지점간의 차이가 l0dB이상 차이를 보였으며, 전체적으로 중간주파수 대역에서 보다 저주파수 대역에서의 편차가 크게 발생하는 것으로 나타났다. 이러한 편차는 저주파수 대역에서의 모드 중첩현상에 의한 것으로 보인다. 현행 바닥충격음 단일지수 평가 방법에 따라 평가한 결과 측정위치에 따라 단일지수 평가값에 2-7dB의 차이를 보였으며 바닥충격음 차음성능 평가에 영향을 줄 수 있을 것으로 판단되었다. 따라서 향후 저주파 대역의 편차를 줄이거나 저음의 모드 중첩에 의한 영향을 배제할 수 있는 측정 혹은 평가 방식의 개선이 필요하다고 사료된다. Measurement of impact sound insulation of floor, by current Korean Standard KS F 2810-2. is to be made with peak levels over 4 point in a receiving room. But it is often the case that there is inconsistency in results at various receiving points in the receiving room. Such variations obviously have effects on the repeatability and reproducibility of measured data. The result shows that there are even 10 dB deviations in 63Hz octave band frequency range and relatively less variations are occurred in other low frequency ranges. Such variations seems to be coming from modal overlaps of the receiving room. According to current rating method of floor impact sound. KS F 2863-2, that may affect on the single number latins scheme. From the result of tests in this study, there are 2dB to 6dB differences in the sin91e number with the combination of measurement points. This means that the reduction of measurement variations from the microphone positions is needed for a better credibility of measurement results.