The sound perception of wood aging is investigated on a Dulcken harpsichord of 1755 from the Museum of Applied Arts in Hamburg, Germany using a Finite-Difference Time Domain (FDTD) model of the harpsichords soundboard. The soundboard thickness was measured on the instrument at 497 positions during strings being deattached and used in the model. Impulse responses were taken on the instrument to estimate the present internal damping by calculating the T60 decay time and used as a model input. By varying the internal damping from this measured damping as a logarithmic decrement, impulse responses were simulated at 52 string positions on both, the 8' and 4' bridge. To estimate the changed sound brightness due to changed internal damping, spectral centroids were calculated from the simulated impulse responses. A dependency of brightness change due to aging on string position was found, where the lower strings have higher brightness, as expected, while the higher strings have decreased brightness. This counterintuitive finding is caused by the frequency-dependent filter effect of changed damping. Future studies need to incorporate viscoelasticity to differentiate this effect further. Furthermore, the attachment of the 8' string to the outer instead of the inner wall, a characteristic feature of Dulcken harpsichords, is investigated using a 3D Finite-Element Method (FEM) model simulation of the whole instrument. No considerable changes on the soundboard tension were found compared to an attachment of the 8' strings to the inner wall, pointing to another reason for this special construction.

翻译：本研究以德国汉堡应用艺术博物馆收藏的1755年Dulcken大键琴为对象，通过建立音板的时域有限差分（FDTD）模型，探究木材老化对声音感知的影响。在琴弦拆卸状态下，于乐器音板497个测量点获取厚度数据并用于建模。通过采集乐器脉冲响应计算T60衰减时间，估算当前内部阻尼值作为模型输入。以对数衰减量形式，从实测阻尼值开始调整内部阻尼参数，分别在8英尺与4英尺琴桥上52个弦位进行脉冲响应模拟。通过计算模拟脉冲响应的频谱质心，评估内部阻尼变化导致的音色亮度改变。研究发现：老化引起的亮度变化与弦位相关，低音弦亮度如预期增高，而高音弦亮度反而降低。这一反直觉现象源于阻尼变化产生的频率依赖滤波效应。后续研究需引入粘弹性理论以进一步区分该效应。此外，通过建立全乐器三维有限元（FEM）模型，模拟研究了Dulcken大键琴特有结构——将8英尺弦系于外壁而非内壁的特征。与内壁系弦方式相比，该构造未引起音板张力的显著变化，表明此种特殊设计应存在其他成因。