Effect of directivity index of a loudspeaker on speech intelligibility

Abstract

There are many rooms are for speech communication purposes such as hall, auditorium, laboratory, meeting hall and lecture room. The main goal for communication is to understand what the speakers are saying and his words are not mistaken for other words. Also there have been identified the factors that affect speech intelligibility are background noise and reverberation time. However, speech intelligibility is also affected by the directivity of loudspeaker. The purpose of this research is to study the effect of directivity of loudspeaker into speech intelligibility with respect to room sizes and loudspeaker configurations. The experiment had been done in three different size rooms with similar rectangular shape. Measurement points (IS points) were selected in each room. The data of SPL and RT60 for each room were quantified by using sound level meter (SA - 27 RION) at Q = 1, Q = 2 and Q = 4. The results of the loudspeaker directivity on the speech intelligibility were represented using %Alcons on DPlot software. In conclusion, loudspeaker arrangements affects the perception of sound at in room samples, and Q = 4 was identified the best directivity configuration for good speech intelligibility. This is due to larger coverage of listening area.