The Jiangnan region of China has long been home to traditional vocal art forms known as "Quchang," such as Kunqu opera and Tanci storytelling. These arts integrate poetic imagery, literati sensibilities, and musical rhythm, remaining vibrant elements of urban culture and spiritual life. The term "Quchang" first appeared in Chen Tingzhuo's "Baiyu Zhai Cihua" (1894). It originally referred to folk song forms, primarily performing short, non-dramatic lyrics ("sanqu xiaoling"). Its meaning later expanded, building upon foundations in minor tunes, Song dynasty lyric poetry, northern and southern metrical patterns, and popular singing, to denote a unique Chinese national art characterized by "creating music from literary texts" and "shaping melodies based on speech tones."

Many "Quchang" performances involve self-accompaniment while singing, as seen in Tanci and Gongdiao. In these forms, the accompanying instruments and the vocal melody merge into one, giving rise to the unique poetic spirit and cultural ambiance of Jiangnan. The instruments used—such as the dongxiao flute among wind instruments, the small sanxian and sihu among strings, and porcelain plates and wine cups among percussion—are typically small, with a low range and a soft, gentle, and light auditory quality. Through a variety of accompaniment techniques described as "welcoming, yielding, supporting, assisting, enveloping, sending off, and continuing," they create a Tai Chi-like interactive rhythm of "complex accompaniment to simple singing, and simple accompaniment to complex singing." This fusion engages multiple sensory dimensions, including vision and touch, to present the poetic characteristics of Jiangnan.

Addressing these features of "Quchang" accompaniment, this study focuses on the pipa, the most frequently used accompanying instrument across various "Quchang" forms. It investigates the relationship between accompaniment and vocal melody, the perceptual experience when singing and playing are separated, and differences in tempo, dynamics, and musical patterns among performers of different age groups. Approximately 15 professional performers from senior, middle-aged, and young generations were selected. Their accompaniment sounds, finger pressure, amplitude, speed, and musical forms were analyzed qualitatively and quantitatively using AI tools. Comparing the similarities and differences in tempo, dynamics, vocal-instrumental treatment, and techniques across the three generations reveals that the traditional essence of "Quchang" pipa accompaniment is gradually eroding and diminishing over time. However, the pipa itself remains indispensable to the artistic integrity of "Quchang" performance. It has established historical value and contemporary characteristics, including the "formulaic" nature of its accompaniment vocabulary, its role in co-creating "thematic" content with the voice, the "uniformity" of its visual form, and its "symbolic" function in constructing artistic conception. This demonstrates the importance and irreplaceability of the pipa, in conjunction with the human voice, in expressing "poetic quality" within Jiangnan "Quchang."