Papers by David Pelegrin Garcia
Known in the past for its spectacular acoustic characteristics, the ancient theatre keeps today a... more Known in the past for its spectacular acoustic characteristics, the ancient theatre keeps today an important role as a modern stage: during the summer season many important theatrical events are organized in the frame of its ancient ruins, keeping alive a tradition that attracts people all around the world. But, without doubts, the actual conditions for the audience are deeply changed, affected by “modern” noises and damaged situation of the theatre itself. The insertion of the scenery elements has also to be considered as a variable that can modify the sound propagation in the theatre, with better or maybe worst results. In this article a research conducted on the acoustic perception of the audience of the Greek theatre of Syracuse is presented. A parametric study realized through a technical software (Odeon ® version 12.1) has been performed considering different scenery conditions, from the empty theatre and by adding different scenic elements to evaluate their influence on passi...
Energy and Buildings, 2014
ABSTRACT The ancient theatres present today two sides: an architectural one, as archaeological si... more ABSTRACT The ancient theatres present today two sides: an architectural one, as archaeological site, and an artistic one, as an entertainment place. This double cultural heritage generates conflicts in the manner of use, so in ancient theatres conservation rules sometimes collide with the intense (and often inappropriate) use during the theatrical summer season.
Journal of Voice, 2014
This case-control designed field study examines the vocal behavior in teachers with self-estimate... more This case-control designed field study examines the vocal behavior in teachers with self-estimated voice problems (VP) and their age- and school-matched voice healthy (VH) colleagues. It was hypothesized that teachers with and teachers without VP use their voices differently regarding fundamental frequency, sound pressure level (SPL), and in relation to the background noise. Teachers with self-estimated VP (n = 14; two males and 12 females) were age and gender matched to VH school colleagues (n = 14; two males and 12 females). The subjects, recruited from an earlier study, had been examined in laryngeal, vocal, hearing, and psychosocial aspects. The fundamental frequency, SPL, and phonation time were recorded with an Ambulatory Phonation Monitor during one representative workday. The teachers reported their activities in a structured diary. The SPL (including teachers' and students' activity and ambient noise) was recorded with a sound level meter; the room temperature and air quality were measured simultaneously. The acoustic properties of the empty classrooms were measured. Teachers with VP behaved vocally different from their VH peers, in particular during teaching sessions. The phonation time was significantly higher in the group with VP, and the number of vibratory cycles differed between the female teachers. The F0 pattern, related to the vocal SPL and room acoustics, differed between the groups. The results suggest a different vocal behavior in subjects with subjective VP and a higher vocal load with fewer possibilities for vocal recovery.
Acta Acustica united with Acustica, 2014
Most European countries have regulatory requirements or guidelines for reverberation time in clas... more Most European countries have regulatory requirements or guidelines for reverberation time in classrooms which have the goal of enhancing speech intelligibility and reducing noise levels in schools. At the same time, school teachers suffer frequently from voice problems due to high vocal load experienced at work. With the aim of improving working conditions for teachers, this article presents guidelines for classroom acoustics design that meet simultaneously criteria of vocal comfort and speech intelligibility,which may be of use in future discussions for updating regulatory requirements in classroom acoustics. Tworoom acoustic parameters are shown relevant for aspeaker: the voice support, linked to vocal effort, and the decay time derivedfrom an oral-binaural impulse response, linked to vocal comfort. Theoretical prediction models for room-averaged values of these parameters are combined with amodel of speech intelligibility based on the useful-to-detrimental ratio and empirical models of signal-to-noise ratio in classrooms in order to derive classroom acoustic guidelines, taking into account physical volume restrictions linked to the number of students present in aclassroom. The recommended values of reverberation time in fully occupied classrooms for flexible teaching methods are between 0.45 sand 0.6 s( between 0.6 and 0.7 si na nu noccupied butf urnished condition)f or classrooms with less than 40 students and volumes below210 m 3 .When designing larger classrooms, adedicated acoustic study taking into account considerations about geometry,material and speaker/audience placements should be made, which can help to increase the voice support and reduce the vocal effort. PACS no. 43.55.Fw,43.55.Hy Received22January 2013, accepted 8May 2014.
Bygg och Teknik, Jan 1, 2011
The Journal of the Acoustical Society of …, Jan 1, 2012
orbit.dtu.dk
School teachers suffer frequently from voice problems due to the high vocal load that they experi... more School teachers suffer frequently from voice problems due to the high vocal load that they experience and the not-always-ideal conditions under which they have to teach. Traditionally, the purpose of the acoustic design of classrooms has been to optimize speech intelligibility. New guidelines are suggested in order to optimize the vocal comfort and the vocal load experienced by speakers. Theoretical prediction models of room-averaged speaker-oriented parameters like voice support or reverberation time derived from an oral-binaural impulse response are combined with empirical models of actual voice and noise level measurements in classrooms. Requirements of optimum vocal comfort, average A-weighted speech levels across the audience higher than 50 dB, and a physical volume higher than 6 m 3 /student are combined to extract optimum acoustic conditions, which depend on the number of students. These conditions, which are independent on the position of the speaker, cannot be optimum for more than 50 students. For classrooms with 10 students, the reverberation time in occupied conditions shall be between 0.5 and 0.65 s, and the volume between 60 and 170 m 3 . For classrooms with 40 students, the reverberation times shall be between 0.7 and 0.75 s and the volume between 240 and 280 m 3 . PACS no. 43.55.Fw, 43.55.Hy Pelegrin-Garcia, Brunskog: Speaker-oriented classroom acoustics design guidelines EURONOISE 2012 10-13 June, Prague
of Electrical Engineering, DTU, under the supervision of Associate Professors Jonas Brunskog and ... more of Electrical Engineering, DTU, under the supervision of Associate Professors Jonas Brunskog and Torben Poulsen. The project was funded by AFA Försäkring; reference 070142. All the experiments presented in this thesis were approved by the Science-Ethics Committee for the Capital Region of Denmark; reference H-KA-04149-g. Cover illustration: Composition with school teaching at Nyvångskolan, Dalby 1 and the anechoic chamber at DTU 2 1 c Jonas P. Andersson, Skånska Dagbladet 2 c Sylvain Favrot, modified with permission.
status: …, Jan 1, 2010
It has been shown that talkers tend to raise their voice in acoustically dry rooms and lower it i... more It has been shown that talkers tend to raise their voice in acoustically dry rooms and lower it in acoustically live rooms. In order to check whether this effect could be related to the Lombard reflex, an experiment has been done, where subjects had to match the loudness of their own voice with a reference tone of 1 kHz, producing different sustained vocalizations, under different simulated artificial responses (cross-modality matching). A correlation was found between the matching voice levels (sound pressure level at the microphone) and the energy of the simulated room impulse response, meaning that the sound reflections at the room boundaries could alter significantly the loudness of one's own voice. In normal (nonamplified) rooms used for speech, the variations in voice levels due to the alteration of the loudness of one's own voice are less than 1 dB on average.
… Environment Center at …
the classroom's air-quality and acoustics, has often been discussed and acknowledged to contribut... more the classroom's air-quality and acoustics, has often been discussed and acknowledged to contribute to the vocal load, but these factors have not been very much investigated with the teacher in action. One purpose of the present project was thus to investigate the voices and the voice use of teaching staffs in their teaching environment and to explore the prevalence of voice problems in Swedish teachers. A second purpose was to explore the teachers' ratings of aspects of their working environment that can be presumed to affect vocal behavior and voice and to measure the teachers' voice use in relation to some of those factors. One more purpose was to clinically assess the voice function in the teachers with self-rated voice problems and compare it to their vocally healthy colleagues. To be able to do comparisons between the teachers, one further objective was to develop and assess a self-rating instrument for the rating of throat-related problems in relation to voice. The purpose was also to develop room acoustic measures related to the voice regulation, and to understand the physical parameters influencing the voice regulation. Finally, the knowledge built up in the project should be used to set up recommendations and design criteria for good speaking environments.
forskningsbasen.deff.dk, Jan 1, 2009
Proceedings of Internoise, Jan 1, 2010
This work shows the results of a preliminary study about the determination of the optimal acousti... more This work shows the results of a preliminary study about the determination of the optimal acoustical conditions for speakers in small classrooms. An experiment was carried out in a laboratory facility with 22 untrained talkers, who read a text passage from "Goldilocks" during two minutes under 13 different acoustical conditions, that combined different kind of background noise and virtual classroom acoustics. Readings from the vocal fold vibrations were registered with an Ambulatory Phonation Monitor device. The speech signal from the talker in the center of the facility was picked up with a head-worn microphone, convolved in real time with the impulse response of the chosen classroom, and reproduced through 29 loudspeakers placed around the subject. In particular, two different primary school classrooms were selected, with very low and very high reverberation time and, for each of them, two speaker positions. The acoustic of the classrooms was simulated with Odeon 9.0. Environmental noise recorded in quiet classrooms, traffic, and babble noise were considered as sources of disturbing noise during experimentation. Several acoustical parameters were calculated from the impulse response measured with an artificial head (corresponding to the mouth-ears path) placed at the talker position while simulating the classrooms. Time histories of the vocal fold vibration readings, with the trend of the fundamental frequency and an estimation of the sound pressure level, sampled every 50 ms, were obtained. From these data the vocal doses Time dose, Vocal Loading Index, Distance Dose, Energy Dissipation Dose, and Radiated Energy Dose were calculated and correlated with the acoustical features of the classrooms.
status: published, Jan 1, 2009
Vocal health is a major concern among teachers, and represents a significant cost for school auth... more Vocal health is a major concern among teachers, and represents a significant cost for school authorities. The physical environment of the teaching room, and not only the background noise, plays a very important role in determining the average voice power levels at which the teachers do speak. When designing the acoustics of a classroom, it is necessary to predict quantitatively the vocal effort that the teacher will experience and the regulations should define an acceptable range for a measure that predicts it. Different measures, including a new magnitude called 'Room Gain', are proposed to predict the vocal effort while talking. The vocal effort is characterized here by the increase of voice power level experienced by a speaker talking in a classroom relative to a reference situation. The results of blind tests in an auditory virtual environment with different simulated classrooms show that speakers lower their voices when the room gain increases.
EAA EuroRegio congress on sound and vibration, Jan 1, 2010
Many teachers suffer from voice problems related to the use of their voices in the working enviro... more Many teachers suffer from voice problems related to the use of their voices in the working environment. The noise generated by students and external sound sources (like traffic noise or neighboring classrooms) is a major problem, as it leads to an increased vocal effort. In the absence of high levels of background noise, the room has also an effect on the talker"s voice. In order to quantify the relative importance of the acoustic environment on the vocal demands for teachers, a laboratory investigation was carried out. Thirteen teachers had to read a text aloud under ten different room acoustic conditions, artificially generated by electroacoustic means. The vocal intensity decreased with the objective parameter support, which quantifies the amount of sound reflections provided by the room at the talker"s ears,relative to the direct sound, at a rate of -0.21 dB/dB. The reading pace decreased with the reverberation time at a rate of 5 words/minute per s. The sensation of comfort and suitability of the rooms for a talker was investigated using a questionnaire. A non-linear relationship between this magnitude and the reverberation time was observed, defining an optimum range around 0.85 s.
The Journal of the …, Jan 1, 2012
The Journal of the …, Jan 1, 2011
The Journal of the …, Jan 1, 2011
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Papers by David Pelegrin Garcia