A controversial discussion in the musical community regards the ability of the harpsichord to produce sound level or timbre changes. The jack velocity (controlled in real time within a musical context) and the plectrum shape (modified by the musician or maker prior to the performance) appear to be the two control parameters at the disposal of the harpsichord makers and players for shaping the sound. This article initiates the acoustical study of the control parameters of the harpsichord, presenting a framework for the investigation of these two parameters with means of experimental mechanics measurement. A robotic finger is used for producing repeatable plucks with various jack velocities and plectrum shapes. The plectrum bending, vibrating string's initial conditions, and radiated sound are recorded and analysed. First, results are obtained from measurements carried out on one string, for four plectrum shapes and four jack velocities. The plectrum shape has been found to have an influence on its bending behavior when interacting with the string; on the string's initial conditions (position and velocity); and on the resulting sound (sound level, spectral centroid, and decay time). The jack velocity does not have an influence on any of the measured quantities.