Abstract (EN):
Speech intelligibility is usually evaluated, by the use of objective parameters, in unoccupied
rooms due to practical considerations. However, under normal conditions, the room
occupancy can increase or decrease the values of speech intelligibility by the effect of the
additional sound absorption present in the room or by the change in S/N ratio. Measurements
were carried out in six churches with and without occupancy. The results show that
occupancy induces a mean increase for the speech intelligibility of ¿STI (STIoccupSTIunoccup)
of 0.050 with the use of a public address system (PA) and 0.035 without a PA.
This increase is caused mainly by the reduction of the room reverberation time, due to the
increased sound absorption and by the reduction of the additional RT induced by the PA
(using loudspeakers with strong directivity oriented towards the congregation area). The
variations in the speech intelligibility values with occupancy can be predicted in churches by
employing new empirical formulations. The decrease in S/N ratio (due to the background
sound level augmentation by the presence of people and by sound level decrease with distance
in the congregation area), or the poor directivity and orientation of the sound sources, could
reduce the speech intelligibility gain in particular cases. Other effects induced by the
congregation, such as the variations of humidity and temperature, generally have negligible
effect on speech intelligibility.
Idioma:
Inglês
Tipo (Avaliação Docente):
Científica
Nº de páginas:
19
Tipo de Licença: