The Sound Quality Characteristics of the Gan Opera Ancestral Temple Theater Based on Impulse Response: A Case Study of Zhaomutang in Leping, Jiangxi Province

Abstract

Based on the relative lack of research on the acoustic characteristics of traditional Gan opera theaters, this paper takes the Zhaomutang theater in Leping, Jiangxi Province, as a case study. By employing impulse response measurements and sound quality index evaluation, this work investigates and analyzes the sound field characteristics of the stage, front patio, Xiangtang, rear patio, and Qintang through field measurements. The results show that the small volume and low ceiling in the stage area lead to higher early reflections and enhanced self-auditory support for performers. The semi-enclosed Xiangtang space exhibits the best speech definition and music clarity. Although the front and rear patios are open-air, they still maintain moderate reverberation and sound energy intensity due to reflections from surrounding surfaces. In contrast, the Qintang has a relatively weak early sound energy because of its volume and functional constraints. Still, its overall reverberation time is not significantly different from that in the other areas. Comprehensive indices indicate that the Zhaomutang theater balances speech intelligibility and musical richness for multifunctional scenarios—ancestor worship, opera performances, and gatherings—thus providing an enhanced viewing experience. These findings offer critical reference points for the protection, restoration, and acoustic optimization of Gan Opera ancestral temple theaters and provide an empirical foundation for further investigation into the multi-space coupling characteristics of traditional theaters.

1. Introduction

Traditional Chinese opera represents a significant facet of China’s cultural heritage. Distinguished by its extensive range of vocal styles, highly stylized performance techniques, and architecturally diverse performance spaces, it has evolved closely with the built environment over centuries [1,2]. The unique acoustic requirements imposed on theater design are not merely a by-product of esthetic choice but are integral to the performance practice. Actors, for instance, must receive robust acoustic support to effectively project both singing and spoken dialogue, while the audience demands precise, resonant sound distribution across varied seating arrangements [3]. Unlike traditional Western theaters, whose design criteria have been shaped by different performance traditions and architectural histories, traditional Chinese theaters exhibit distinct forms, structures, and performance forms that give rise to unique acoustic regularities [4].

Internationally, relatively comprehensive studies have been conducted on the acoustics of traditional performance spaces such as ancient Greek and Roman open-air theaters [5,6,7,8,9,10]. For instance, Farnetani et al. [5] compared acoustic conditions across different historical periods by integrating field measurements and scale model tests, while D’Orazio et al. [6] carried out in-depth examinations of sound quality distribution at the Bayreuth Festspielhaus through impulse response measurements and numerical simulations. Büttner et al. [11] investigated Japanese Kabuki theaters’ spatial layout and acoustic characteristics, revealing that variations in stage configuration and material absorption between traditional Eastern and Western theaters can significantly affect audience perception. Collectively, these findings offer insights into the acoustic mechanisms of historic theaters and the coupling effects in multi-space environments and establish methodological foundations for exploring other forms of traditional performance spaces.

Recent research has increasingly emphasized conserving, renovating, and rejuvenating historical theaters. Scholars have applied refined numerical simulations alongside on-site impulse response testing to assess how renovation measures impact acoustic conditions and audience experience [12,13,14,15,16]. For instance, Pérez-Aguilar et al. [14] analyzed the acoustic performance of the Banda Primitiva de Llíria theater across different historical epochs, providing valuable guidance for future preservation efforts. Bevilacqua et al. [15,16] further contributed by using digital reconstructions of the ancient theater of Pompeii and the San Carlo theater in Naples to determine the acoustic characteristics under varied scenarios. This growing body of work underlines the importance of integrating historical authenticity with modern acoustic optimization—a critical factor when preserving cultural heritage while ensuring that performance spaces meet contemporary acoustic standards [17,18,19,20,21].

Traditional Chinese opera stages exhibit considerable diversity within China, influenced by regional cultures, repertoire specifics, and these spaces’ multifunctional societal roles. Most existing studies have concentrated on representative opera stages in provinces such as Shanxi, Fujian, Guangdong, Beijing, and Shanghai. Venues like the Sanshan Guild Hall [22], the Wanfu Stage [23] at the Foshan Ancestral Temple, the ancient theater of Shanxi [24], some temples [25], and traditional palace theaters [26] have been investigated using simulation and on-site measurements. These studies have revealed that such venues often feature higher spatial openness and intricate coupled sound fields. In particular, courtyard-style layouts introduce complex pathways for sound energy exchange and multiple reflection patterns between open areas and enclosed spaces such as the Xiangtang, wing rooms, and corridors [27,28]. Such spatial configurations result in diverse acoustic behaviors that merit detailed investigation.

However, despite the extensive research on many traditional Chinese opera venues, the acoustic properties of ancestral temple theaters associated with Gan opera in Jiangxi have received relatively little attention. Gan opera, listed in the third batch of China’s National Intangible Cultural Heritage, is characterized by various vocal techniques and performance forms that demand unique architectural acoustics [29]. Leping in Jiangxi Province, renowned for its “ancient stage construction skills” (recognized in the fourth batch of the national intangible cultural heritage list in 2014), holds a vibrant cultural legacy in stage construction and performance traditions. The ancestral temple theaters in Leping are multifunctional spaces for theatrical performances, ancestor worship, and communal gatherings. Their floor plans and vertical dimensions differ significantly from those of palatial structures, guild halls, or typical temple stages, thus necessitating specialized acoustic research that can address the simultaneous demands of ritual performance, musical expression, and social interaction [30].

The Zhaomutang theater, constructed during the Ming Dynasty, is an early example of an ancestral theater that has largely retained its original timberwork, carvings, and beam structures [30]. Its design exhibits prominent regional characteristics, featuring a classic “three-entry” layout and incorporating elevated platforms and open patios to satisfy visual and acoustic requirements [31]. Despite its historical and artistic significance—evidenced in its architectural configuration, decorative style, and construction methods—the theater’s acoustic properties remain underexplored. A thorough investigation of the Zhaomutang’s sound quality parameters is vital to deepening our understanding of how the Gan opera performance environment emerged and informing the preservation and sustainable use of this important cultural asset. Recently, attention has also turned to historical buildings with semi-open or multi-courtyard designs. For instance, Martín-Castizo et al. [32], Bevilacqua et al. [33], and Zhang et al. [34] have employed measurements and computer simulations to elucidate acoustic distribution patterns in multi-space coupled settings, thereby demonstrating how different acoustic indicators can significantly influence performance outcomes and guide conservation strategies. This expanding research scope underscores a broader shift toward investigating how semi-open architectural forms, especially those that blend indoor and outdoor elements, can shape and enrich the overall acoustic experience in historical settings [35,36].

In light of these observations, the present study employs impulse response testing to perform systematic field measurements in both the stage and audience areas of the Zhaomutang theater, aiming to clarify the sound field distribution and key acoustic attributes of this Gan opera ancestral temple theater. Building on previous investigations of other regional or structural theater types, this research not only examines the influence of multi-space coupling on acoustic parameters but also explores how an ancestral temple theater can optimally balance speech intelligibility, musical richness, and loudness distribution under varied functional demands (including ancestor worship, performances, and communal gatherings). By undertaking a comprehensive analysis of the Zhaomutang’s sound quality indicators, this paper seeks to (1) identify the theater’s reverberation characteristics, early reflection patterns, and sound-level distribution; (2) investigate how its intricate spatial configuration affects both audience experience and performance quality; and (3) offer an empirical acoustic foundation for the preservation and enhancement of traditional Gan opera theater spaces.

2. Materials and Methods

2.1. Case Study

The Zhaomutang theater is in the middle of the old street of Yongshan Village, Yongshan Town, Leping City, Jiangxi Province, China. Its construction can be traced back to the Chongzhen period of the Ming Dynasty (1628–1644 AD), and it was renovated in the third year of the Guangxu period of the Qing Dynasty (1877 AD) and again in the 1990s [30]. As shown in Figure 1 and Figure 2, the overall floor plan of the theater is rectangular, incorporating multiple spaces—such as the gatehouse, stage, front patio, Xiangtang, rear patio, and Qintang—to form a typical “three-entry” sequence. The building gradually increases in elevation from the entrance to the Qintang, symbolically emphasizing the Qintang’s visual and ceremonial importance.

Table 1. Basic dimensions of each subspace of the Zhaomutang theater.

Space	East–West Width (m)	North–South Width (m)	Net Height (m)	Interior Volume (m3)	Elevation (m)
Stage	8.7	5.4	3.2	150	2.8
Front patio	8.7	5.2	/	/	0
Xiangtang	14.7	12.5	6.2 (9.5) *	1414	0.8
Rear patio	6.2	2.7	/	/	0.8
Qintang	14.7	6.3	4.4	407	1.5

* There is a sloping roof, with a lowest point of 6.2 m and a highest point of 9.5 m.

presents the basic dimensions of each subspace in the Zhaomutang theater.

The main structure of the theater adopts a “through-beam” system that integrates both through-beam and raised-beam styles. Its façade is a double-eaved hip roof flanked by 35 m long wind and fire gables, which serve as firebreaks while creating favorable conditions for lateral sound reflections. The stage is adjacent to the gatehouse, and a wooden partition separates the stage from the backstage area. This design not only facilitates backstage costume and prop organization but also helps to enhance the sound energy projected from the stage toward the audience.

From the perspective of spatial sequence, after passing the gatehouse is the elevated stage, followed by the front patio of the first entrance. The front patio, open and lacking a roof, is frequently used for large-scale daytime performances or gatherings and can accommodate substantial audiences. Adjacent to the north side of the front patio is the semi-indoor Xiangtang, featuring a slightly raised floor. It serves vital functions such as performance viewing, ceremonial activities, and guest receptions; the audience often sits in this area. Beyond the Xiangtang lies the rear patio, and the final entrance is the Qintang, where ancestral tablets are enshrined. The Qintang holds the highest status within the theater complex as the core location for ancestor worship rituals. This subdivided spatial configuration supports multiple functions and offers diverse listening experiences: the semi-enclosed Xiangtang, the Qintang, and the open patio interconnect, creating a multi-zone sound field environment. During a performance, the actor’s voice travels through the front patio and Xiangtang to reach the rear patio and, potentially, the Qintang. Consequently, the acoustic conditions profoundly influence the audience’s perception of vocal clarity and the overall comfort of viewing the performance.

The Zhaomutang theater is representative of functionality, spatial layout, and construction period. First, it is an early example of a traditional Gan opera ancestral temple theater. It illustrates key features of southern stage design, such as vertically tiered spaces, an open patio, and acoustical “sound-gathering” elements. Second, it has undergone multiple renovations yet preserves its core spaces’ authenticity, offering a rare research opportunity for studying the acoustic characteristics of ancient theaters.

2.2. Sound Quality Measurement Solution

Gan opera music is characterized by dry singing, free intonation, “rolling white,” and “rolling singing,” emphasizing vocal and recitative performance. To ensure that the audience can hear the actors clearly, the performers must possess strong vocal projection and crisp, accurate enunciation. Still, the viewing area must exhibit suitable reverberation frequency characteristics, sufficient loudness, and sound speech intelligibility. To investigate the actual acoustic performance of the Zhaomutang theater, on-site impulse response measurements were conducted under empty conditions. The experiment used the interrupted sound source method, and the measurement procedure followed the basic requirements of ISO 3382-1 [37]. A wireless building acoustic measurement system (AHAI 1002) was employed, comprising an acoustic measurement analyzer (ISV 1101), a 1/2-inch free-field microphone (AWA 14425), a dodecahedron loudspeaker (2032A), a power amplifier (2044A), a tablet computer, and a router. During the experiment, the dodecahedron loudspeaker was stimulated by a pink noise signal to emit sound, forming a broadband noise of steady-state reverberation in the room. The microphone collected the impulse response at each measurement point, and after A/D conversion, it was input into Brüel & Kjær DIRAC software (type 7841) to calculate key sound quality parameters. To minimize the influence of environmental noise and human activity, measurements commenced at 11 p.m., and the background noise level was continuously monitored to ensure it remained negligible.

Figure 3 illustrates the measurement setup and the distribution of measurement points. The sound source (S) was placed at the center of the stage, and the microphone array was designed to capture the acoustic experience from both the stage area and the auditorium. Measurement points were distributed on the right side of the central axis, adhering to ISO 3382-1 symmetry guidelines. A total of six measurement points (W1–W6) were positioned on the stage to analyze how performers perceive their voices from different locations. In comparison, 28 measurement points (F1–F8, X1–X12, R1–R4, Q1–Q4) were distributed throughout the audience area to evaluate the effects of direct sound, early reflections, and coupled sound fields in each region. Because the front patio is large and relatively regular, microphone placement there accounted for both axial distance from the stage and lateral sound attenuation. Meanwhile, the Xiangtang displays more pronounced acoustic coupling with the patio, prompting a denser placement of microphones to capture detailed data on reflections and reverberation patterns. Although the rear patio and Qintang primarily serve ritual functions and occupy smaller areas, some measurement points were still arranged to represent their acoustic environments.

The subsequent data processing focused on core acoustic metrics—namely reverberation time (T₃₀), definition (D₅₀), clarity (C₈₀), and sound strength (G)—across the 125–4000 Hz frequency range. T₃₀ characterizes the decay of sound energy over time; D₅₀ and C₈₀, respectively, reflect speech intelligibility and musical articulation; and G quantifies the total sound energy perceived by audiences in different sections, a factor of particular relevance for opera performances that demand adequate loudness. Additionally, to elucidate the effects of ceiling openings and side-wall reflections in this multi-space configuration, the energy distribution within the impulse response—during both the early stage (0–50 ms) and the middle-to-late stage (50–200 ms)—was also examined. To improve the repeatability and accuracy of the measurement results, each measuring point was measured three times, and the average was taken. The uncertainty of the measurement results was calculated according to the provisions of ISO 3382-1. The standard deviations of T₃₀ at all measuring points were less than 0.07 s, 0.05 s, 0.04 s, 0.03 s, 0.02 s, and 0.01 s at 125 Hz, 250 Hz, 500 Hz, 1000 Hz, 2000 Hz, and 4000 Hz, respectively, which are all within the acceptable range.

3. Results

3.1. Pulse Response Analysis

An analysis of the impulse response sequences within the first 200 ms at both stage and audience positions is presented in Figure 4. Across the stage, Xiangtang, rear patio, and Qintang, many high-amplitude early reflections were detected within the first 50 ms (highlighted by the boxed areas in the figure), and the initial delay gap was generally less than 20 ms. This finding indicates a strong sense of acoustic intimacy. On the one hand, the shorter initial delay gap effectively enhances the immediate clarity of speech and singing. On the other hand, multiple early reflection peaks contribute to more extraordinary musical richness [2]. This phenomenon can be primarily attributed to the thoughtful architectural design of the Zhaomutang theater and the sound-diffusing effects introduced by its internal structural elements.

In contrast, the front patio exhibits only three major early reflection peaks within 50 ms. One key reason is its higher degree of openness, lacking a ceiling component that could generate denser reflections, thus limiting the early sound energy [22,27]. In the later decay phase (50–80 ms), most spaces still exhibited some reflection signals. Still, their amplitudes were substantially lower than that of the direct sound and the principal early reflection peaks. This observation suggests that the theater does not suffer from pronounced echoes or imbalanced resonances. It is worth noting that the impulse response of the W2 measurement point shows more than ten strong early reflection peaks within 50 ms, and the sound energy decays relatively slowly. The main reason for this phenomenon is that the stage volume is relatively small, and the ceiling height is low, which forms strong acoustic feedback in the stage area. The surrounding columns and short-range reflections from the top diffusion structure will enhance this feedback.

3.2. Sound Quality Parameter Analysis

The sound quality parameters were calculated separately for the stage and auditorium and then subjected to statistical analysis across octave bands. Figure 5 shows the mean and standard deviation of the sound quality parameters at each measurement point. At mid-frequencies (500 Hz, 1000 Hz), the average reverberation time (T₃₀) at the stage was approximately 0.86 s, while it was around 1.03s in the auditorium. Notably, the 125 Hz band exhibited a slight increase, aligning with the trend of stronger low-frequency reverberation commonly observed in southern courtyard-style theaters [22,28].

Overall, the stage yields D₅₀ values ranging between 0.70 and 0.76 and similarly high levels of C₈₀ (7.6–9.1 dB) and G (15.7–16.4 dB). These findings indicate that the stage design facilitates effective speech transmission and provides adequate clarity and intensity for musical performances. In the auditorium, however, the D₅₀ (0.42–0.51), C₈₀ (1.4–3.4 dB), and G (5.1–7.2 dB) were comparatively lower—likely due to diminished late reflections in open or semi-open areas. Nevertheless, these values remained within acceptable ranges and did not lead to excessive sound attenuation or distortion for traditional opera performances [27].

3.3. Spatial Distribution and Variation Analysis of Auditorium Sound Quality Parameters

To further explore the acoustic behavior of different subspaces in the auditorium, 500 Hz and 1000 Hz were chosen as a representative frequency band, and Figure 6, Figure 7, Figure 8 and Figure 9 illustrate the results for comparative purposes. The data reveal that the mean T₃₀ values for the front patio, Xiangtang, rear patio, and Qintang were 0.96 s, 1.03 s, 1.03 s, and 1.08 s, respectively, and, at 1000 Hz, they were 1.02 s, 1.05 s, 1.05 s, and 1.07 s, indicating that the reverberation distribution is relatively uniform. Although the front patio exhibits weaker early reflections, its reverberation time remains relatively high, primarily due to acoustic coupling with adjacent areas such as the Xiangtang and rear patio. As sound decays quickly in the open area, other nearby reflecting surfaces help compensate for the energy loss.

In terms of D₅₀ average values, the Xiangtang had the highest value, 0.50 and 0.53 at 500 Hz and 1000 Hz, respectively. It was followed by the front patio (0.44, 0.46), the rear patio (0.42, 0.44), and the Qintang (0.36, 0.38). The central part of the auditorium thus maintains good speech definition. The Xiangtang’s superior early energy ratio stems from its enclosing side walls and overhead structure, which produce denser early reflections and a moderate volume that promotes stable clarity in the audience area. Notably, the D₅₀ at X6 is relatively low because the measuring point lies beneath the center of the sloping roof, which is higher and has fewer structural elements, resulting in reduced top reflections. The front patio measurements near the stage (F1–F4) were markedly lower in D₅₀ than those in F5–F8 (closer to Xiangtang), suggesting that diffraction from the stage floor diminishes early sound energy at F1–F4. By contrast, F5–F8 benefit from supplemental early reflections originating in the Xiangtang. Although the open ceiling in the rear patio limits early reflections, its smaller area and acoustic coupling with the Xiangtang yield a D₅₀ higher than that in the Qintang.

Figure 8 illustrates the C₈₀ results, with average values of 0.7–2.5 dB at 500 Hz and 1.2–3.0 dB at 1000 Hz for each space, indicating satisfactory musical fullness—enabling the audience to experience intimate sound. The F5–F8 points near the front patio and Xiangtang can reach 4.2–4.6 dB (500 Hz) and 4.7–5.1 dB (1000 Hz), surpassing measurements closer to the stage and demonstrating the significant impact of coupled spaces on early and late sound energy distribution. The differences in C₈₀ between the rear patio and Qintang are attributed to variations in area and enclosure: the smaller rear patio, connected directly to the Xiangtang, balances early reflection and late decay more effectively, while the Qintang’s greater distance and narrower passage to the patio lower this metric.

In actual listening conditions, adequate sound intensity is needed to ensure that the D₅₀ and C₈₀ remain within suitable limits. Figure 9 shows that the average G values of the front patio, Xiangtang, rear patio, and Qintang are 8.4 dB, 7.2 dB, 4.6 dB, and 3.6 dB at 500 Hz and 8.0 dB, 6.6 dB, 3.9 dB, and 2.7 at 1000 Hz, respectively. These results generally confirm the spatial suitability for both speech and musical performances. As expected, G values decline at the rear patio and Qintang, correlating with the increased distance from the sound source and consistent with common acoustic principles governing sound diffusion and absorption.

Notably, F5–F8 exhibit significantly higher G values than F1–F4, indicating a strong relationship between diffraction shielding and early reflections. As shown in Figure 10, the stage floor partly obstructs direct sound propagation to F1–F4, forcing diffraction to play a more prominent role and resulting in lower recorded levels than in F5–F8, which, though positioned farther away, benefit from improved reflected energy. Notably, the maximum distance between the sound source and measuring points reached 24.8 m. By elevating the terrain, the theater design effectively reduces the sound path length to the audience area and minimizes sound absorption by those seated in front. The Zhaomutang’s tiered profile design and overall elevation strategy ensure high-quality audio-visual experiences for back-row audiences while accommodating the theater’s multifunctional requirements.

4. Discussion

Judging from the sound quality measurement results, the Zhaomutang theater achieves a relatively balanced acoustic distribution across the stage and the various viewing/performance areas. The late decay in the open spaces does not severely compromise the overall reverberation, while semi-enclosed or smaller-volume areas effectively enhance early sound energy through appropriate reflections. The reverberation time of the Zhaomutang auditorium (1.03 s at mid-frequencies) meets the requirements for drama theaters in China’s code for the architectural acoustical design of theaters, cinemas, and multi-use auditoriums (GB/T 50356-2005) (0.95–1.25 s) [38], so the Zhaomutang can realize the performance function of modern drama. If further optimization of the viewing and performance sound field is desired, targeted acoustic modifications—such as adding localized reflecting surfaces or adjusting the stage floor opening—could address the diffraction shielding in the front patio near the stage and the weaker early sound energy in the Qintang. These interventions would help further improve the sound quality without compromising the historical integrity of the ancestral temple theater.

As an ancestral temple theater, the Zhaomutang embodies a unique combination of openness and semi-enclosure: the sound energy interaction between the patio and the Xiangtang imparts an attenuation profile reminiscent of open-air venues yet partial enclosures preserve a certain level of reverberation and clarity. Driven by dual functions—entertainment and ancestor worship—the theater employs a compromise in spatial layout and acoustic design, ensuring that performers on stage and audiences in areas such as the Xiangtang and patio benefit from moderate reflections and sufficient loudness. Compared with ancient Greek and Roman theaters, the Zhaomutang enhances specific frequency bands through its composite space, although differences in clarity arise among zones due to multi-space coupling [5,7,39]. Relative to other temple-style theaters in China, its open-air portion reduces late reverberation and internal reflections, thereby maintaining a more transparent listening environment [25]. In summary, the Zhaomutang theater demonstrates the flexible coordination of architectural function and acoustic effect, offering a new perspective for in-depth research into the performance and ritual value of ancient Chinese ancestral temple theaters.

5. Conclusions

By integrating impulse response testing with sound quality parameter evaluations, this study systematically analyzed the multi-space sound field characteristics of the Zhaomutang theater, a representative Gan opera ancestral temple theater in Leping, Jiangxi Province. The Zhaomutang holds significant value in its architectural design and cultural heritage, retaining a high degree of authenticity as a Ming Dynasty relic. Its multi-entry spatial configuration and multifunctional usage scenarios provide a valuable case study for investigating the acoustic properties of traditional theaters in southern China. The principal findings are as follows:

(1)

The stage’s compact size, combined with a low ceiling, generates multiple strong early reflections within 50 ms, with a short initial delay gap. This design feature ensures that performers receive high-intensity self-auditory support for singing and spoken dialogue, especially within crucial linguistic frequency bands.

(2)

Although the front and rear patios are open at the top, their acoustic coupling with the Xiangtang and the adequate reflection from surrounding walls allows for moderate reverberation and an acceptable sound intensity distribution. This partially open environment does not excessively degrade the overall acoustic quality.

(3)

The semi-enclosed Xiangtang is the primary viewing and performance space, exhibiting the highest speech definition and musical clarity. In contrast, the Qintang has a relatively weaker early sound energy due to its location and function. However, its overall reverberation time remains comparable, reflecting a balance between the demands of ancestor worship ceremonies and performance requirements.

This study primarily focused on empty-field measurements, and the full-field state (i.e., with an audience present) was not thoroughly examined. Additionally, the influence of varying sound source positions remains underexplored. Future research should investigate full-field conditions incorporating subjective and objective evaluations to deepen our understanding of ancestral temple theaters’ spatial coupling mechanisms and acoustic attributes. Such insights would offer a scientific basis for adapting and preserving ancient theaters, ensuring that their cultural and functional legacy endures.