In this section objective and subjective data collection methodology for singer’s voice dosimetry and perception of the rooms will be explained for the first Laboratory phase. A total of 32 singers participated in the first laboratory phase. The questionnaire design was developed and validated in this stage for the following stages, in addition the first vocal loading measurements were taken at this stage.
3.7.1.
Questionnaire Design
The questionnaire was developed through discussions with several experienced singers and by conversations with the Royal Academy of Music Opera Department staff for a deeper understanding of the perception of the acoustic parameters and singers concerns due to their
30 vocal performance based on their singing environment. The final questionnaire was composed of two sections: “About you” section and “Room questionnaire” section.
3.7.1.1.
“About You” Questionnaire
“About you” questionnaire consists of seven questions designed to gather information about the singer’s personal information such as their age, gender, voice type and their singing background. The questionnaire is given in Appendix E. The singers were asked to complete the questionnaire prior to their voice dosimetry measurements.
3.7.1.2.
Room Questionnaire
The “Room questionnaire” was developed to gather information about the singers’ perception of the rooms using questions about room acoustic parameters and their performance in each room. This section was composed of nine questions of which the singers were asked to rate on a seven-point Likert-type scale, first five parameters were related to room acoustic parameters and the last four were about their perceived effort and overall impression of the rooms. Questions are listed in Table 5 and the ratings of each question can be found in Table 6.
Table 5 Room Questionnaire parameters
Q1 Loudness
(How do you perceive your sound level in this room?)
Q2 Clarity
(How would you rate the degree to which notes are distinctly separated in time and clearly heard?)
Q3 Reverberance
(How would you rate the persistence of sound in this room?)
Q4 Background noise
(How would you rate the background noise levels in this room?)
Q5 Size of the room
(How would you rate the size of this room?)
Q6 Pleasure of singing in this room
(How would you rate your pleasure of singing in this room?)
Q7 Voice feeling
(How would you rate your voice feeling in this room?)
Q8 Singing effort (How would you rate your effort singing in this room?) Q9 Overall Impression (How would you rate the acoustical quality of this room?)
The main purpose of the “Room questionnaire” was to correlate the subjective data to the measured room data in order to find out room acoustic parameters that are most related to Opera singer’s subjective ratings. In order to understand whether the questionnaire language makes sense to singers two extreme environments: Reverberant and Anechoic chambers and a relatively more realistic environment: Semi-reverberant chamber were used with an expectation of extreme answers to the extreme conditions and relatively preferable answers to the Semi-reverberant chamber. The singers were asked to complete the questionnaire right after they finish singing in each room. The original questionnaire can be found in Appendix F.
Table 6 Room Questionnaire: 7-Point Likert-type scale rating and
questionnaire parameters
3.7.2.
Voice Dosimetry measurement design using APM
The aim was to find the best method to collect vocal loading data of the singers which demonstrates their vocal use at the practice rooms for the field stage. The voice dosimetry measurements were undertaken using APM.
APM was attached on the singer as explained in Section 3.1.1. For the accuracy of the data, APM was calibrated for each singer’s voice prior to the measurement as described in the APM manual. [62] For calibration process, the device has a microphone fixed at 15 cm from
the end of a metal bar placed on the subjects’ mouth, as seen in Figure 4 below. The singers were asked to locate their upper lip to the bar and phonate “A” vowel from their quietest level to their loudest until the software shows enough data points to form a linear trend line. The aim of this process is to introduce the full range of the singer to the device. The whole process including the attachment of the device takes five minutes and was repeated prior to vocal dosimetry measurement of each singer. After the completion of calibration process, APM is disconnected from the computer and with the device left attached on the singers. At the first laboratory phase, “Scales” were chosen as a vocal loading exercise in order to collect voice dosimetry data as this exercise demonstrates their daily exercise in a practice room. The singers were asked to sing scales on “A” vowel for two minutes on a comfortable pitch that they self-selected. For the consistency of the measurements the singers were asked to sing the same scale on the same pitch and on the same vowel in three acoustic chambers: reverberant chamber; semi-reverberant and anechoic chamber, respectively.
Likert Rating 1 2 3 4 5 6 7 Q1 Loudness extremely
weak
very
weak weak sufficient loud very loud
extremely loud
Q2 Clarity extremely unclear very little clear a little clear sufficient clear very clear extremely clear
Q3 Reverberance extremely
dry very dry dry balanced reverberant
very reverberant
extremely reverberant
Q4 Background
noise not audible
very
weak weak acceptable loud very loud
extremely loud Q5 Size of the room extremely small very
small small sufficient large
very large extremely large Q6 Pleasure of singing extremely
bad very bad bad sufficient good very good
extremely good
Q7 Voice feeling extremely
weak
very
weak weak as usual strong very strong
extremely strong Q8 Singing effort extremely less than usual quite less than usual less than usual as usual
more than usual quite more than usual
extremely more than usual Q9 Overall impression extremely
bad very bad bad sufficient good very good
extremely good
32
Figure 4 APM calibration process
This order was kept the same for each singer. Since the conditions represent extreme environments semi-reverberant chamber was chosen to be the second test environment since the acoustic parameters of the chamber is in between the anechoic and reverberant chambers. To ensure that the singers sing on the same pitch and to remind the singer the start note, a piano application from a smart phone was used and the start note was played prior to the measurement in each room. The total singing duration in each chamber was two minutes non-stop (two-minute scales) and the total measurement duration was six minutes (three chambers).
3.7.3.
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 rooms (chambers) further analysis were made using One-way analysis of variance (ANOVA) test for repeated measures as same people were tested in different conditions. To explore where the difference occurs post-hoc statistical tests were conducted.