Investigations into vocal doses and parameters pertaining to primary school teachers in classrooms

Investigations into vocal doses and parameters were carried out on 40 primary school teachers (36 females and 4 males) in six schools in Italy, divided into two groups of three, A and B, on the basis of the type of building and the mid-frequency reverberation time in the classrooms, which was 1.13 s and 0.79 s, respectively. A total of 73 working-day samples were collected (66 for females and 7 for males), from which 54 traditional lessons were analyzed separately. The average value over the working days of the mean sound pressure level of the voiced speech at 1 m from the teacher's mouth was 62.1 dB for the females and 57.7 dB for the males, while the voicing time percentage was 25.9% and 25.1%, respectively. Even though the vocal doses and parameters did not differ for the two school groups, the differences in the subjective scores were significant, with enhanced scores in group B. A 0.72 dB increase in speech level per 1 dB increase in background noise level, LA90, was found during traditional lessons, as well as an increase in the mean value of the fundamental frequency with an increase in LA90, at a rate of 1.0 Hz/dB

Mismatches between objective parameters and measured perception assessment in room acoustics: a holistic approach

Psychoacoustic research in the field of concert halls has revealed that many aspects concerning listening perception have yet to be totally understood. On the one hand, the objective room acoustics of performance spaces are reflected in parameters, some standardized and some not, but these are related to a limited number of perceptual attributes of human response. In general, these objective parameters cannot accurately describe the acoustic details due to their inherent simplification. Under these premises, impulse responses (576 receivers) are measured in 16 concert halls, according to standard procedures, and the perception and satisfaction of the occupants of the rooms are evaluated by completing a questionnaire during live concerts. Correlation analyses and multidimensional scaling (MDS) techniques have been applied to spatial and multi-band averaged values of the acoustic parameters studied (18), and the average values of users responses (1284) to the questionnaire items (26). As a first result, correlations between objective parameters and users responses show that transversality exists between them. Secondly, hierarchical clustering produces the classification of survey questions in 7 hierarchical classes. On the other hand, a lack of tuning between objective parameters and perceptual responses is observed on applying MDS analysis to the ordination of the venues from a subjective assessment and a subjectiveobjective assessment. Finally, although the results show the mismatch between objective parameters and subjective responses, a model of subjective global evaluation of the acoustics of the room from data of three orthogonal acoustic parameters is implemented, revealing a reasonably good fit.The authors wish to express their gratitude to P. Bustamante for his help, to all those who participated as listeners in this study, and to management and staff of each hall for facilitating acoustic measurements and allowing distribution of the questionnaires in their theatres. This work has been financially supported by FEDER funds and by the Ministry of Science and Technology with references Nos. BIA2003-09306, BIA2008-05485, BIA 2010-20523, and BIA 2012-36896.Giménez Pérez, A.; Cibrián Ortíz De Anda, R.; Cerdá Jordá, S.; Girón, S.; Zamarreño García, T. (2014). Mismatches between objective parameters and measured perception assessment in room acoustics: a holistic approach. Building and Environment. 74:119-131. doi:10.1016/j.buildenv.2013.12.022S1191317