The Effect Of Source Directivity On Chinese Speech Intelligibility In Room

In the research of auditorium acoustics, omni-directional sound source is mostly used in experimental measurement and acoustic simulation. However, not all the real sound sources are omni-directional sources. This paper chooses a classroom as the study object, through objective acoustical measurement, computer simulation, subjective evaluation and auralization methods, studies the effect of source directivity on Chinese speech intelligibility in room.In the aspect of the effect of source directivity on the measurement results of speech intelligibility, omni-directional source and directional source are employed to measure objective acoustical parameters which are relative to speech intelligibility and valuate subjective speech intelligibility. The results show that source directivity almost has no effect on EDT,T30, has significant effect on C50 at medium and high frequencies and has significant effect on STI; Source directivity has significant effect on the subjective evaluation of speech intelligibility in real room, and the speech intelligibility obtained by omni-directional source are lower than the speech intelligibility obtained by directional source and human voice.The simulated objective speech intelligibility parameters obtained by software ODEON and the subjective evaluation obtained by using auralization technique are analyzed by objective and subjective comparison. The results show that source directivity almost has no effect on EDT,T30, has significant effect on C50 at medium and high frequencies and has significant effect on STI; Source directivity has significant effect on the speech intelligibility of auralized sound signals. The speech intelligibility of the sound signals generated by directional source(human voice) is better than the speech intelligibility of the sound signals generated by omni-directional source.The research shows source directivity has significant effect on Chinese speech intelligibility in room. The speech intelligibility will be underrated if omni-directional sound source is used for acoustical measurement and simulation.The research results provide significant guidance and valuable reference for the measurement and prediction of speech intelligibility.