Proporción que representa la inversión en el Activo Total de la matriz o coligante
Nota 2 Bases de Presentación de los Estados Financieros Consolidados
Data collection methods were determined in two Laboratory phases. The design decisions regarding data collection methods started at the first laboratory phase and finalised in the second laboratory phase. The finalised methods were then used in the field stage undertaken at the RAM practice rooms.
A total of 30 singers participated in the second laboratory phase. The questionnaire developed in the first laboratory phase was used in this phase as well, but the voice dosimetry measurements were developed further.
3.8.1.
Voice Dosimetry measurement design using APM
The second laboratory phase was performed since the results for voice dosimetry data measured in the first laboratory stage did not show any significant difference in the three extreme acoustic environments. In order to understand whether this might be due to duration
or the type of exercise, the singing duration was decided to be increased by an additional two minute to sing a song. Since each singer has different repertoire with different vocal range and since the aim was to compare the scores of the same singer in each room rather than to make a comparison between singers, the singers were asked to choose a song that they are comfortable with and to keep singing the same song for each environment. As in their real practice environment, they were asked to sing the scales first as a warm-up and then the song. For the second laboratory phase, the total singing duration in each chamber was four minutes non-stop (two-minute scales, two-minute song) and the total measurement duration was 12 minutes (three chambers). The data collected with APM for each chamber and each type of singing were separated by selecting the time frames relevant to each measurement using the APM software and then analysed separately. The measurement procedure was the same as the 1st laboratory phase.
3.8.2.
Voice Dosimetry measurement design using SLM
Another reason for performing a second laboratory phase was that the first laboratory phase results showed that APM measures the time-average sound pressure level (SPL) data based on voicing duration rather than SPL in octave bands. Therefore for the sound pressure level measurements for each octave band frequency, a sound level meter was decided to be used and sound power levels for each octave band frequency were calculated from the measured sound pressure levels for each singer. Frequency based analysis were conducted separately for males and females in order to examine whether there’s any difference in sound power levels between rooms at different frequencies for each gender. As the aim of this phase was to finalize the measurement method for the field stage, consideration was also given to time efficiency and the singers comfort. Since the practice rooms for the field measurements will be booked for only a certain amount of time not long enough to attach, calibrate and detach more than one device for each singer and since the singers will already have APM attached on them; wearing a second device might limit their ability to sing. Therefore instead of a head-worn microphone, a Class 1 NOR140 sound level meter fixed at 1.5 m height and 1.5 m. distance from the singer was used. Before the measurements, the sound level was calibrated with its own calibrator. In each chamber condition, the singers were asked to stand at the same point. The measurement positions in the chambers are given in Appendix G.
3.8.2.1.
Singer’s Sound Power Level Calculation
In order to calculate sound power levels for each octave band, measured sound pressure levels for each octave band frequency were used. For Reverberant chamber, Sabine’s statistical theory of room acoustics[35] was used as seen in Equation 11, where L
REV is the
measured sound pressure level, Lw is the sound power level and Rc is the room constant.
L
REV= Lw +10log(
4 Rc)
34 Rc was calculated for each octave band using Equation 12 where S is the total area of room surfaces, α is the average sound absorption of those surfaces at each octave band. Sound absorption for each octave band was calculated via Equation 4 using measured T30 values.
R
c= (
(𝟏−𝐒𝛂)𝐒𝛂)
Equation 12[35] For Anechoic chamber, Equation 13 which gives the direct sound pressure level was used: LDIRECT is the direct sound pressure level measured in the anechoic chamber, Lw is the sound
power level, Q is the directivity factor, and r is the distance of the receiver from the source (1.5m).
L
DIRECT= Lw +10log(
𝑸 𝟒𝝅𝒓𝟐)
= Lw -20logr -11
Equation 13[35] For Semi-reverberant chamber and for all the RAM practice rooms the sound power levels were calculated for each octave band frequency using Equation 14 where LTOTAL is the sumof direct and reverberant sound pressure levels, Lw is the sound power level, r is the distance of receiver from the source and Rc is the room constant. Rc for each room was calculated for each octave band frequency using Equation 12 where S is the total area of room surfaces, α is the average sound absorption of those surfaces at each octave band. Sound absorption for each room at each octave band frequency was calculated via Equation 4 using measured T30 values.
L
TOTAL= Lw +10log((
𝑸 𝟒𝝅𝒓𝟐) + (
𝟒 𝐑𝐜))
Equation 14[35]3.8.2.2.
Analysis of Collected Data
To find out whether there’s a statistically significant difference in the singers’ objective (voice dosimetry) and the subjective (questionnaire) data among the chambers further analysis were conducted using One-way analysis of variance (ANOVA) test for repeated measurements of the same participants under different test conditions. To explore where the difference occurs post-hoc tests were conducted. In addition, in order to validate that the room questionnaire was clearly understood by the singers, a comparison was made between the room questionnaire results of First Laboratory phase and Second Laboratory phase by conducting One-way between groups analysis of variance (ANOVA) test as the participants were different for each phase.