EURASIP Journal on Applied Signal Processing 
Volume 2004 (2004), Issue 7, Pages 934-948
doi:10.1155/S111086570440211X

Sound Synthesis of the Harpsichord Using a Computationally Efficient Physical Model

Vesa Välimäki,1 Henri Penttinen,1 Jonte Knif,2 Mikael Laurson,2 and Cumhur Erkut1

 1Laboratory of Acoustics and Audio Signal Processing, Helsinki University of Technology, P.O. Box 3000, Espoo 02015, Finland
2Sibelius Academy, Centre for Music and Technology, P.O. Box 86, Helsinki 00251, Finland
Received 24 June 2003; Revised 28 November 2003

Abstract

A sound synthesis algorithm for the harpsichord has been developed by applying the principles of digital waveguide modeling. A modification to the loss filter of the string model is introduced that allows more flexible control of decay rates of partials than is possible with a one-pole digital filter, which is a usual choice for the loss filter. A version of the commuted waveguide synthesis approach is used, where each tone is generated with a parallel combination of the string model and a second-order resonator that are excited with a common excitation signal. The second-order resonator, previously proposed for this purpose, approximately simulates the beating effect appearing in many harpsichord tones. The characteristic key-release thump terminating harpsichord tones is reproduced by triggering a sample that has been extracted from a recording. A digital filter model for the soundboard has been designed based on recorded bridge impulse responses of the harpsichord. The output of the string models is injected in the soundboard filter that imitates the reverberant nature of the soundbox and, particularly, the ringing of the short parts of the strings behind the bridge.