Acoustics design for optimal speech intelligibility of Velodrom Nasional Nilai Negeri Sembilan

Optimal speech intelligibility in sport arenas is required not only for the information of athletes and their performances but also for crowd control and security purposes. However, designing room for optimal speech intelligibility in large volume sport arenas is more challenging when the portion area in it requires different degree of speech intelligibility. This paper presents acoustics works at the Velodrom Nasional. The acoustics of the Velodrom were evaluated using EASE software. Acoustics parameters were investigated once placement of loudspeakers and their respective aiming were completed. Initial reverberation time at the frequency 1 kHz of the empty Velodrom was found to be in 7 seconds. This was due to sound reflective finishes on the walls and ceiling of the Velodrom. Thus, initial speech intelligibility results in the audience seating were also poor with Alcons score of more than 15 percent. Then, the Velodrom was rigorously simulated in search for better speech intelligibility by experimenting with different finishes on the ceiling, and with different loudspeaker placements and aiming. In conclusion, the measured reverberation time at the frequency 1 kHz of the Velodrom was about 3.5 seconds. Speech intelligibility, in the audience seating, has improved tremendously to Alcons 9 percent