One reason for a significantly increased prevalence of voice problems can be poor room acoustical conditions in the environment in which teachers usually work, and that is why acoustics in schools is a topic of vital importance.

This research project born as a collaboration between, the Polytechnic University of Turin and the South Bank University of London, the aim of the thesis is to investigate about relationships between the teachers’ vocal effort and the acoustics of the spaces.

A group of ten volunteer teachers (two female and eight males) was monitored in different spaces: anechoic chamber, semi-reverberant chamber, reverberation chamber, a classroom and a gymnasium in order to understand how vocal effort is affected by different acoustic conditions.

Two types of tests were carried out in different environments and furthermore two device were used to monitor teachers: APM and Voice Care. The last one, in particular, is a new prototype studied by the Polytechnic of Turin, and so it was possible compare each other.

After each performance in different venues, a questionnaires about teachers’ personal perceptions was administered to subjects in order to discover whether there was any correlation between the objective and subjective data.

The dissertation is structured in four chapters: the first one is a background about definitions, standards, states of arts as concern vocal effort, the second one instead focuses on the acoustics of the spaces.

Chapter three is about the research project, the tests have been carried out are deeply analyzed and all the results, both objective than subjective are reported and compared.

Finally, the last section is about the acoustic simulation, in particular through the acoustic software Catt, it made possible suggesting proposals in order to improve the acoustic conditions of a gymnasium.

1.3.1 Intelligibility indexes

1.4 State of art: teacher’s vocal effort

1.4.1 Definitions

1.4.2 Prevalence

1.4.3 Consequences

1.4.4 Causes

1.5 Measurement devices

1.5.1 Vocal signal acquisition

1.5.1.1 State of art technology: contact microphones

1.5.1.1.1 APM

1.5.1.1.2 Voice Care

CHAPTER II: Acoustics of the Spaces

2.1 ISO 3382

2.2 Acoustical parameters

2.2.1 Reverberation Time (T)

2.2.1.1 Two methods to obtain T during measurements:

impulse response method and Interrupted noise one

2.3.1 Early Decay Time (EDT)

2.4.1 Background Noise Level

2.5.1 Strength of Sound (G)

2.6.1 Clarity (C50)

2.7.1 Definition (D50)

2.3 State of Art

2.3.1 Teachers'vocal effort and acoustics into classrooms

2.3.2 P.E. teachers'vocal effort and acoustics into sport halls

2.4 Acoustic measurement device: Norsonic 140

CHAPTER III: The Research project

3.1 Research environments

3.1.1 London South Bank University Acoustic Laboratory

3.1.1.1 Anechoic chamber

3.1.1.2 Reverberation chamber

3.1.1.3 Semi-reverberant chamber

3.2.1 Michael Sobel Sinai School, London

3.2.1.1 Gymnasium

3.2.1.2 Classroom

3.3.1 Acoustic characteristics of the environments

3.3.1.1 Acoustical measurement procedure

3.3.1.2 Measurement results

3.2 Monitoring tests

3.2.1 Short monitoring

3.2.2 Long monitoring

3.2.3 Sample of teachers

3.2.4 Questionnaire

3.2.5.1 Short tests results

3.2.5.1.1 Anechoic chamber, semi-reverberant chamber,

reverberation chamber results

3.2.5.1.1.1 Expected uncertainty: comparison

between calibration and monitoring SPL curves

3.2.5.1.1.2 Comparison between different groups..

3.2.5.1.1.3. Subjective results

3.2.5.1.1.4 Comparison between subjective and

objective results

3.2.5.1.2 Gym and classroom results

3.2.5.1.2.1 Expected uncertainty: comparison

between calibration and monitoring SPL curves

3.2.5.1.2.2 Comparison between a P.E. teacher

and an ordinary teacher

3.2.5.1.2.3. Subjective results

3.2.5.1.2.4 Comparison between subjective and

objective results

3.2.5.2 Long test results

3.2.5.2.1 Gymnasium and classroom Voice Care results

3.2.5.2.1.1 Expected uncertainty: comparison

between calibration and monitoring SPL curves

3.2.5.2.1.2 Comparison between a P.E. teacher

and an ordinary teacher

3.2.5.2.2 Gymnasium APM results

3.2.5.2.2.1 Comparison between APM and Voice

Care results

CHAPTER IV: Simulation for the acoustic project: Catt v 9

4.1 The software

4.1.1 The auralization

4.2 Acoustic improvement of the gymnasium

4.2.1 The gymnasium acoustic model

4.2.2 Acoustic suggestions

4.2.2.1 Horizontal solutions

4.2.2.2 Vertical solutions

4.2.3 Results

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