음향시뮬레이션을 이용한 노후된 성당의 음향성능 개선

Abstract

성당 음향은 전례 예식의 명확한 음성전달과 성가의 풍부한 음향효과를 동시에 고려해야 한다. 이는 강당의 음향설계나 다목적 음악당과는 다른 음향 특성을 가지기 때문에 설계 단계에서 성당의 특성에 맞는 음향설계가 필요하다. 설계 단계에서 음향 시뮬레이션을 이용하여 음향설계를 하는 것이 가장 바람직하지만, 성당의 재건축이나 개·보수공사 시 음향성능 개선을 위한 음향설계 및 시공이 동반되는 것도 하나의 방법이라고 사료된다. 본 연구는 성당 본당 노후화로 인해 리모델링을 계획 중인 부산지역의 D건물을 대상으로 실내음향을 측정하였다. D건물의 음향 측정값을 비슷한 규모의 S건물의 측정값과 비교하고, 각 건물 제실자를 대상으로 설문조사를 실시하여 측정값과 비교해보았다. 또한, 선행 연구를 통해 제안된 값과 3D 모델링을 이용한 D건물의 음향 시뮬레이션 값을 비교하고 검증하였다.

The catholic church acoustic system shall consider both accurate sound travel and the acoustic effect from the voices of the choir. Given the acoustic design has different acoustic characteristic from other multipurpose concert halls, acoustic design that fits to such characteristics from the early design is a must. Using acoustic simulation at design stage is very desirable, but acoustic design and application when rebuilding or refurbishing the church is also regarded to be one of the solutions.

In this study, room acoustics was measured in building D in Busan, which will undergo remodeling because of deteriorated main hall of the catholic church. The values measured were compared with those of building S in similar size, and the data obtained as a result of interviewing with the occupants was also compared to the values measured. And the values from the previous studies and acoustic simulation data obtained using 3D modeling were compared for verification purpose. To improve the acoustic performance of building D, the carpet on podium on the 1st floor was replaced with the marble which has lower sound absorption rate and the glass in front side on the 2nd floor was removed to simulate the improvement effect. And the result and proposed values were compared and evaluated, considering sound absorption by human body.

Consequently, the results from the study include the followings. 1. RT60 of building D was relatively short for its volume and thus both the D50 and C80 were within the proposed range. However, as they were measured when it’s vacant, the parameters when it’s full of the people are expected to go beyond the range of proposed values. And referring to the response to the survey, it’s necessary to prolong the reverberation time to some extent.

2. Building S had extended RT60 when it’s empty, but it’s estimated that RT60, D50 and C80 would be similar with the proposed values. However, considering the survey result and measured values, deviation by evaluation point appeared to be significant, requiring improving acoustic performance in partial.

3. Compared to omnidirectional speaker, simulation values of RT60 and EDT were higher while speech intelligibility D50 and C80 were lower, indicating various parameters were uniform, which was attributable to failure of considering the difference between 3D model and building D and surrounding environment except temperature and humidity during measuring.

4. When comparing the simulation values after improvement with the proposed values, RT60 was 0.05 seconds longer and D50 on both the 1st floor and 2nd floor were within a range of 30∼40% which was proposed for concert hall and when it comes to C80, it’s similar with the Jordan’s ±2dB on both the 1st floor and 2nd floor. The values are expected to mostly stay within the range of proposed values, even in case of considering the measured values and simulation values before improvement.

5. The values of other locations than evaluation point appeared to exceed the range of proposed values, which could possibly be improved with PA system installed within the building.

The improvement model modifying the part of finish material of building D was proposed in this study, and the simulation values of the improvement model were found to be within the range of proposed values from the previous studies.