Fabre François, Le Carrou Jean-Loïc, Chomette Baptiste
Sorbonne Université, CNRS, Institut Jean Le Rond d'Alembert, Equipe Lutheries-Acoustique-Musique, F-75005 Paris, France.
Univ Lyon, Ecole Centrale de Lyon, CNRS, ENTPE, LTDS, UMR5513, 69130 Écully, France.
J Acoust Soc Am. 2023 Oct 1;154(4):2337-2348. doi: 10.1121/10.0021332.
Central Africa harps are string instruments, often anthropomorphic, serving an essential cultural role. Compared to pedal harps, their body is small in size with a soundboard mainly made of animal skin and a neck made of a wood beam. In this paper, a physical model is developed as a tool for assessing the specificities of these musical instruments, from a vibro-acoustic perspective. The modeling strategy is based on the modal Udwadia-Kalaba formalism which is a multibody substructuring technique. Input modal parameters of the body and the strings are experimentally identified and the main steps of the estimation procedures are detailed. The reliability of the physical model is investigated via the comparison between simulated and experimental data for several plucking configurations. Different hypotheses are assessed such as the string/neck coupling which proves to strongly influence the dynamic response of the body when there is a coincidence between string and neck modal frequencies. The inclusion of geometrical nonlinearities proves to be of major importance, even for a weak plucking, as it allows qualitative representation of double frequency terms in the simulations. Overall, physical simulations of the soundboard motion are in good agreement with measurements indicating characteristic features of the instrument are captured.
中非竖琴是弦乐器，通常具有拟人化特征，发挥着重要的文化作用。与踏板竖琴相比，它们的琴身较小，音板主要由动物皮制成，琴颈由木梁制成。在本文中，开发了一个物理模型，作为从振动声学角度评估这些乐器特性的工具。建模策略基于模态乌德瓦迪亚 - 卡拉巴形式主义，这是一种多体子结构技术。通过实验确定琴身和琴弦的输入模态参数，并详细介绍了估计过程的主要步骤。通过比较几种拨弦配置的模拟数据和实验数据，研究了物理模型的可靠性。评估了不同的假设，例如弦/颈耦合，当弦和颈模态频率一致时，它被证明会强烈影响琴身的动态响应。即使对于较弱的拨弦，几何非线性的纳入也被证明至关重要，因为它允许在模拟中定性表示倍频项。总体而言，音板运动的物理模拟与测量结果吻合良好，表明该乐器的特征已被捕捉到。
