A Case Study on Soundscape Analysis for the Historical and Ethnic Village of Dong Nationality in Zhaoxing County

Zhiyong Deng; Kexin Dong; Danfeng Bai; Kaicheng Tong; Aili Liu

doi:10.3390/acoustics3020016

,

and

¹

Music College, Capital Normal University, Beijing 100048, China

²

College of Resource Environment and Tourism, Capital Normal University, Beijing 100048, China

^*

Author to whom correspondence should be addressed.

Acoustics2021, 3(2), 221-234;https://doi.org/10.3390/acoustics3020016

This article belongs to the Collection Historical Acoustics

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Abstract

A soundscape is a sound environment of the awareness of auditory perception and social or cultural understandings. Based on a soundscape investigation in 2019 in the historical and ethnic village of Dong Nationality in Zhaoxing County, Guizhou Province of China, a case study on the soundscape analysis with the acoustical sound pressure level and an impressive sound event or soundmark is introduced in this paper. Furthermore, in order to determine the subjective soundscape experience and its influence by the length of background music listening, the independent variable “Length of Listening” and six adjective pairs, such as “Monotonous” to “Rich”, “Clamorous” to “Quiet”, “Stressing” to “Relaxing”, “Boring” to “Vivid”, “Noisy” to “Musical” and “Disliked” to “Preferable” are chosen to obtain a curve-fit, which shows that the length of the music listening background has a higher correlation to the subjective experience, and no sufficient attention has been paid to the context of the traditional soundscape preservation, ethnic music and quiet and soft ambient sounds.

Keywords:

soundscape; sound level mapping; curve-fit; Dong Nationality

1. Introduction

A soundscape, as suggested by Schafer, is a sound environment of the awareness of auditory perception and social or cultural understandings with the three features of keynote, sound signal and soundmark [], or as defined by ISO, an “acoustic environment as perceived or experienced and/or understood by a person or people, in context” []. Domestic scholars mostly regard Chinese gardens and urban parks as research objects, for the collection, measurement and acoustical evaluation of soundscapes of noise control or architectural engineering design projects [,,,].

In the case of soundscape investigation and its human awareness, so much research has been carried out to prove the importance of protecting soundscapes in historical areas [,,]. As a whole, sound sources, acoustic environment and its subjective evaluation, individual behaviors, social and demographical characteristics are the factors that influence soundscapes in historical areas []. Semantic differential analysis is often used to acquire the subjective evaluation [], and then, for Chinese people, some adjective pairs which are easy to understand such as “Clamorous” to “Quiet”, “Boring” to “Vivid”, “Common” to “Divine”, “Traditional” to “Modern”, “Rough” to “Smooth”, “Directional” to “Omni”, “Far” to “Close”, “Strong” to “Weak” and “Disliked” to “Preferable”, were also suggested as the common semantic parameters to evaluate soundscape experience in historical areas [].

Based on 37 typical binaural-recorded samples and the questionnaire on site in the historical and ethnic village of Dong Nationality in Zhaoxing County of Guizhou Province of China in 2019, a case study on the soundscape analysis with the acoustical sound pressure level, curve-fit and an impressive sound event or soundmark is introduced in this paper. The aim of this case study is to determine which kind of keynote, sound signal, soundmark to preserve or restore, the subjective semantic soundscape experience and its influence by the three features and the length of background music listening.

2. Methods

2.1. Case Study Area and Samples

The area for this case study is the famous village of Dong Nationality in Zhaoxing County (Zhaoxing village for short) located in the southeast of Liping County, Southeast Miao and the Dong Autonomous Prefecture of Guizhou Province. It is one of the largest Dong villages with lots of drum towers and an area of 180,000 m² surrounded by mountains. For the local people of Dong Nationality, the drum tower is a special building for religious, social, traditional music and dancing, performing activities and fire warning. A strong drum beat can be heard all over the village when it works.

The shape of this area is shown in Figure 1 []. In 2009, the traditional music of Dong Nationality called Kam Grand Choirs (Dong Grand Song) was listed in the World Intangible Cultural Heritage list by United Nations Educational, Scientific and Cultural Organization (UNESCO).

Figure 1. The location of Zhaoxing village.

All the samples involved in this paper were recorded on site in Zhaoxing village as shown in Figure 1, including the County Road 886 (the main street), the riversides, the Museum, the Performance Area, the Dong Garden, the Main Gate and the North Gate, four characteristic alleys, Alley 1, Alley 4, Alley 5 and the Xicai Alley, and five primary drum towers, the Lituan Drum Tower, the Xintuan Drum Tower, the Rentuan Drum Tower, the Yituan Drum Tower and the Zhituan Drum Tower.

There are 18 binaural soundwalk recordings, 19 binaural location recordings used to analyze the sound level mapping and to extract the keynotes, sound signals and soundmarks. Additionally, the interviews of 125 respondents (71 males, 54 females) on site from 16 to 22 August of 2019 are used to analyze the curve-fit.

2.2. Algorithm of Acoustic Parameter LA_eq

In Figure 2, we use the equivalent sound pressure level in dBA (LA_eq) to represent the sound level of each sample as Equation (1):

L A_{e q} = 10 \lg (\frac{1}{n} \sum_{i = 1}^{n} 10^{0.1 L_{p_{i}}})

(1)

Figure 2. Sound level mapping (in LA_eq) of Zhaoxing Village during the day (left) and night (right, the estimated value for riverside soundwalk at night).

n—the numbers of equal duration section within a sample in the time domain, L_pi—the sound pressure level in dBA of each duration section.

2.3. Recording and Measuring Techniques

According to the complex situation on site and the local regulatory policy, it is impossible to use visible or big acoustic measuring equipment like large microphones or sound meters. Therefore, for the recordings, all the samples were binaurally recorded by an Apple iPhone X with a pair of Sennheiser AMBEO smart headsets (calibrated with a standard sound level meter in advance) plugged into the ears of the recording engineers. Additionally, especially for the soundwalk recordings, soft soles were required to avoid the sounds of footsteps. In order to simulate a listening situation of common people, recording engineers could freely or naturally do some slight body movements such as turning the head and squats during the soundwalks.

Then, for the measurement of LA_eq, firstly, according to the length of a sample, we cut each sample into 10 or more sections, calculated the sound pressure level (L_p₀) in dBA with the microphone’s sensitivity and the equivalent voltage level just at the first section of sample; then the L_pi can be calculated as Equation (2), and finally, the LA_eq, can be calculated by L_pi as Equation (1).

L_{p_{i}} = L_{p_{0}} + Δ L_{u_{i}}

(2)

L_p₀—the sound pressure level just at the beginning of each sample, ΔL_ui—the difference between the equivalent voltage level of each section and that of the first section of this sample; the equivalent voltage level can be directly read from the recording software.

2.4. Subjective Evaluation and Its Curve-Fit Method

In order to determine the subjective soundscape experience on site and its influence by the length of background music listening, a short questionnaire on site based on the semantic differential analysis was design as shown in Table 1.

Table 1. Subjective Soundscape Experience Evaluation Questions and Adjective Pairs.

The independent variable Length of Listening (LOL) acquired by the question of “How long do you listen to music on average every day? (in minutes)”, and six questions with the corresponding adjective pairs, differentiated in semantics as “Monotonous” to “Rich”, “Clamorous” to “Quiet”, “Stressing” to “Relaxing”, “Boring” to “Vivid”, “Noisy” to “Musical” and “Disliked” to “Preferable” were chosen to obtain a curve-fit. Then, the linear and quadratic curve-fit is used to show the length of music listening influence on the subjective soundscape experience represented by the average evaluation score of each adjective pair.

2.5. Soundscape Features

Keynote

Keynote is a term derived from musicology, which refers to the first primary note in a particular musical scale. It is usually the fundamental tone. Keynote sounds are those which are heard by a particular lineage frequently enough to form a natural or social sound environmental background against other sounds. Examples might be the sound of wind for a valley village, or the sound of traffic in a big city. Most of the keynote sounds are lower in the sound pressure level, stable in the frequency spectrum, and then often ignored by the people.

Sound Signal

The sound signals contrasted by keynote sounds are those which directly give attention or a particular information, such as traffic alert and church bell sounds, which may often be organized into some codes permitting messages to be transmitted quickly and clearly. However, for now, signals are also expanded to refer to some special sound events or sound objects in the foreground.

Soundmark

The term soundmark is derived from landmark to refer to a special sound event which is native, unique and specially regarded or noticed by the people in a community, a village, a city, a country or, etc. Once a soundmark has been identified, its nativity, sociality and history related to its native time–spatial identifiability [], deserves to be protected.

3. Results

3.1. Sound Level Mapping

The Sound level mapping (in LA_eq) is shown as Figure 2.

3.2. Soundscape Features Analysis

According to Figure 2 and the results of the experts’ listening sessions, the soundscape analysis including keynotes, sound signals (signals for short) and soundmarks in detail is listed in Table 2.

Table 2. Soundscape features analysis.

In order to analyze the soundscape features of Keynote, Sound Signal, and Soundmark suggested by Schafer [], with all the samples played in headphones, two listening sessions (one for the soundwalk recordings, one for the location recordings the next day) were carried out in a lab for 5 experts to extract the three features and give some comments on the tourist flow, tourist behavior, tourism routing, the form of business and the aspects of ethnomusicology (Table 2), according to following guidelines.

3.3. Curve-Fit Mapping

The average evaluation score without the unit of each interval in the question for the independent variable LOL is shown in Table 3, and the linear or quadratic curve-fit mappings are shown in Figure 3.

Table 3. Subjective evaluation score.

Figure 3. Curve-fit mapping results of average scores (y-axis in the suitable scale for each question) distribution with the “Length of Listening (LOL)” (x-axis).

4. Discussions

4.1. Soundscape Features Analysis

According to Figure 2 and Table 2, except the main gate and the cross of the main street and the river, there was a similar distribution of other streets and alleys during the day and night. As the experts’ comments on sample No.1, No.10, sample No.III and sample No.A in Table 2, the sound level of the cross was higher at night due to so many bars full of people at night in this cross, while that of the main gate was lower, because few people access the village by the main gate at night. For sample No.3 of the main street, there were more people at night but a lot of traffic in the daytime, so there was a similar sound level both at the day and night.

In general, the sound levels were changing from 55 dBA to 85 dBA both in the day and night, and it is much noisier in the middle of the village than both in the south and north ends. The keynotes were mainly the natural sounds, traffic and business noise, with the sound signals of car horns. It was learned about from the local people that the drum beats from the drum towers were the most important sound signal for the local daily life for the religious, social, traditional music and dance performing activities and fire alert, but they were rarely heard in recent years. In this famous village, the traditional music and dancing performance is the most important soundmark obviously; however, according to the experts’ comments, without a traditional cultural background as in the past, it is just like a newfangled performance for the tourists and an obligatory task for the local people. Therefore, both for the tourists and the local people, for the function of this kind of traditional music and dancing performance, they may have different interpretations and expectations. Additionally, in other words, the further research can be focused on a semantic analysis for the perception and understanding of keynotes, signals, soundmarks.

4.2. Relationships between Length of Listening and the Semantics

Base on Table 2 and Figure 3, some possible relationships between Length of Listening (LOL, the independent variable in Table 1) and the semantics (represented as the subjective evaluation scores in Table 3) could be shown in the curve-fit mappings with three types of the linear increasing, the optimal threshold and the worst threshold.

4.2.1. The Linear Increasing

The linear increasing for the adjective pairs such as “Monotonous” to “Rich” (Q.1), “Boring” to “Vivid” (Q.4) and “Disliked” to “Preferable” (Q.6). The accumulation of length of listening to music could lead to the improvement of “Rich”, “Vivid” and “Preferable” perception of the soundscape. It can be also found that people’s joviality, happiness and preference brought by the accumulation of intensity, and this increasing phenomenon is more in line with our daily feelings.

4.2.2. The Optimal Threshold

The optimal threshold of 30–60 min for the adjective pairs such as “Clamorous” to “Quiet” (Q.2) and “Stressing” to “Relaxing” (Q.3). This is different from the result of linear increase in Type I, while Type II is a kind of interval for the optimal threshold. The highest points of curve-fit mapping for “Clamorous” to “Quiet” and “Stressing” to “Relaxing” both appear at 30–60 min. The negative effect of lower or higher intensity for “Quiet” or “Relaxing” is nervousness or panic, while a moderate intensity will achieve a good effect more consistent with our cognition.

4.2.3. The Worst Threshold

The worst threshold of 30–60 min for the adjective pair of “Noisy” to “Musical” (Q.5). In contrast of Type II, there is the worst threshold of 30–60 min for the “Noisy” to “Musical” perception. It is obviously that the musicality of soundscape is more complicated; that is, no more attention has been paid to the music content.

5. Conclusions

According to results and discussions, for which kind of keynote, sound signal, soundmark to preserve or restore, the traditional music and dancing could be the most important soundmark with keynotes of natural sounds, local dialects and slight tourists or bossiness noise when the most important sound signal—drum beat is restored to work in its traditional ways.

For the subjective semantic soundscape experience and its influence by the length of background music listening, the perceptions of “Rich”, “Vivid” and “Preferable” have a positive link with an accumulation of daily listening time, while the perceptions of “Quiet” and “Relaxing” perceptions need a suitable length of not too little or too much daily listening time. The “Muscial” perception for the soundscape is more complicated, with a worse score in a much more suitable daily listening time. Finally, the historical and ethnic Zhaoxing village was originally full of natural sounds, songs of insects or birds, traditional music, dancing and cultures. However, however, due to the influence of the modernization, the keynotes and soundmarks are not clear, with an increasing sound pressure level of kinds of noise. The excessively high volume of traffic, amplifiers, and performance leads to more noise than the traditional music itself, which also shows that the length of background music listening has a higher correlation to the subjective experience, and no sufficient attention has been paid to the context of the traditional soundscape preservation, ethnic music and the quiet and soft ambient sounds.

Additionally, many more questions were revealed in this case study, such as the reason why the drum beat could not be heard in recent years, the relationship between the subjective experience and the contents of the keynote, sound signal, soundmark, the “Musical” or “Artistic” perception, the necessity and the ways to restore the traditions of historical or ethnic soundscapes, are worthy of more research.

Author Contributions

Conceptualization, Z.D. and A.L.; methodology, Z.D.; software, D.B. and K.D.; validation, K.D., A.L. and Z.D.; formal analysis, K.T.; investigation, D.B., K.D. and K.T.; resources, Z.D.; data curation, K.T.; writing—original draft preparation, K.D. and D.B.; writing—review and editing, Z.D. and A.L.; visualization, D.B., K.D. and K.T.; supervision, A.L.; project administration, Z.D. and A.L.; funding acquisition, A.L. and K.D. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by NSFC (Beijing, China), grant number 41871130 (2019, hosted by Liu Aili) and Capital Normal University (Beijing, China), grant number 90 (2019, hosted by Dong Kexin).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Conflicts of Interest

The authors declare no conflict of interest.

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