The evaluations of speech intelligibilty of stadium speaker systems

With the recent advancements in technology, electro acoustic system designs in stadiums have also progressed. In conjunction with this fact, system manufacturers have started producing specialized series of speakers for stadiums. These improvements are also closely related to speech intelligibility in stadiums. This thesis focuses on the integration of speech intelligibility in stadium design in accordance with FIFA (Football International Federation Association) standards. Specifically, speakers of two different types and orders have been analyzed in terms of their effects on speech intelligibility. Speakers, which are placed as line array and conventional/point source orders are directed to the same receiver points in both projects. Except the characteristic features of speakers, all measurement parameters in stadiums are the same for both projects. Line array speakers are designed as 7 speaker clusters. The directivity patterns of the clusters have been determined with the speaker angles, delays and gain differences, with the highest possible coverage of all the audience areas. A total of 252 speakers have been used. On the other hand, 72 point source speakers in groups of 2, have been used in order to cover the higher and lower audience areas respectively. Although the measured results of both system designs are compatible with the FIFA standards, there are notable discrepancies. In some areas of the stadium, where the amplitude of the point source speakers is equal to line array speakers, point source speakers show superior speech intelligibility than the line array speakers. Besides the vast difference between the numbers of speakers, point source speakers outpaces the line array speakers in speech intelligibility. They provide a wider distribution angle whereas the line arrays provide a long throw signal distribution on the vertical plane