Towards constructing a historically-grounded gesture-timbre space of Guqin playing techniques

Abstract

Guqin is an ancient Chinese zither instrument known for its timbral variability and the vital role timbre, as opposed to melody or rhythm, played in its classical compositions. Numerous ancient texts dating back to the 1500s provided gestural guidelines of defined Guqin playing techniques and recommendations on timbre aesthetics. It’s also suggested in these texts that small deviations in gestures have significant impact on resulting timbres. Nevertheless, traditionally and even today, Guqin pedagogies are largely metaphoric, mind instead of body, and include limited elaboration on recommended gestures. To digitize and concretize the sonic implications in Guqin gesture-timbre writings, and variegate within the oversimplified vocabulary of playing techniques, this study aims to design and record a dataset of isolated, short, representative Guqin sounds labeled by gestural data. The sounds in question are curated by extracting ancient text, where emphasis on gesture-induced timbral difference is mentioned. We decompose the notion of gesture into nine degrees of freedom for both hands, including left/right hand position, fingers used, point of contact, left/right hand temporal coordination, etc. We define a ladder of gestural data at various levels, ranging from discrete labels of playing techniques, the aforementioned degrees of freedom to continuous signals acquired by high-speed camera with automatic hand-tracking system. We analyze in time-frequency domain timbres resulting from conventional playing gestures and their systematically “perturbed” versions. We investigate the correlation between timbres and their underlying gestures, via methods derived from multidimensional scaling.