Research About Effects On The Early Reflected Sound In The Front Row Of The Auditorium Caused By The Ceiling Of The Concert Hall

The concert hall is a building for performing arts which demands a top-ranked requirement of the room-acoustic. It is also a main palace for listening symphonies and other natural music. There is few concert hall which has an excellent sound quality in the world because of the high requirements of architectural acoustics. Some famous concert halls also are pointed out that there are some acoustical problems. The most-mentioned problem is the lack of the early reflected sound in the front row in a concert hall.The lack of the early reflected sound in the front row in a concert hall is a significant and difficult problem in acoustical design of the concert hall. The area of the front row has the best view in the concert hall. However it is the area with poor sound quality because of the lack of the early reflected sound which caused by the close distance from the sound source and the long distance from the side wall and the ceiling. The main focus of this dissertation is to find the reasons for the lack of the early reflected sound, especially to study the influence from the ceiling.The results of this research are obtained from the relationship between the ceiling height and the early reflected sound by using computer simulation software. Specifically, the research is to observe the early reflected sound in the front row by using the impulse response method in which a typical plan concert has different types and heights of the ceiling. This study implements the impulse response experiments in tree seats from the front row with five different ceiling heights and different angles of inclination of the ceiling. Form the research, it can be obtained that(1)To reduce the ceiling height is conducive to increase the early reflected sound and reduce the time interval between the direct sound and the early reflected sound.(2)To reduce the ceiling height can bring the vertical reflected sound from the ceiling forward which lead to delay the lateral reflected sound.