Introduction: As one of the most ancient Chinese string instrument, the zither-like Guqin possesses a unique timbre that is often described as serene, meditative and ethereal. Guqin sound can be characterized by its rich acoustic features, which can be systematically understood using the source-filter theory. The theory, commonly applied to human voices, can be used to explore the acoustical characteristics associated with Guqin’s subtle timbre.
Objectives: The study aims to investigate the acoustic characteristics of the Guqin by comparing the variations across three major playing techniques (source) and eight finger techniques (filter). Key acoustic differences were explored.
Methods: High-quality Guqin sound samples were obtained for each playing and finger technique. The data were analyzed using Praat to extract relevant acoustic parameters, including Long-Term Average Spectrum (LTAS), spectral moments measures such as centroid, skewness, kurtosis, slope, and harmonic spectral ratio, and formant distributions. The source-filter framework was applied to interpret how the instrument’s timbre varies across techniques.
Results: Preliminary results revealed significant acoustic differences among the different playing and finger techniques. Distinct spectral characteristics, such as spectral centroid shifts and variations in spectral slope and skewness, were observed. LTAS and formant analysis further highlighted noticeable contrasts, indicating that each technique uniquely modifies the acoustic output.
Conclusions: The findings demonstrate that the Guqin’s rich timbral variations can be objectively captured using acoustic features. This study validates the application of the source-filter theory beyond vocal studies and provides insights into how nuanced playing techniques shape the instrument’s sound.