Deriving the plucking point location along a guitar string from a least-square estimation of a comb filter delay

This paper focuses on the extraction of the excitation point location on a guitar string by an iterative estimation of the structural parameters of the spectral envelope. In a simple digital physical model of a plucked-string instrument, the resonant modes translate into an all-pole structure while the initial conditions (a triangular shape for the string and a zero-velocity at all points) result in a FIR comb filter structure. The delay D of the comb filter can be expressed as the product of the relative plucking position R and the fundamental period T/sub o/. We propose a general method to estimate the plucking point location, working into two stages: starting from a measure related to the autocorrelation of the signal as a first approximation, a least-square estimation is used to refine the comb filter delay value to better fit the measured spectral envelope.

[1]  Julius O. Smith,et al.  Extensions of the Karplus-Strong Plucked-String Algorithm , 1983 .

[2]  Julius O. Smith,et al.  Efficient Synthesis of Stringed Musical Instruments , 1993, ICMC.

[3]  Vesa Välimäki,et al.  Physical Modeling of Plucked String Instruments with Application to Real-Time Sound Synthesis , 1996 .

[4]  Matti Karjalainen,et al.  Extraction of Physical and Expressive Parameters for Model-Based Sound Synthesis of the Classical Guitar , 2000 .

[5]  Vesa Välimäki,et al.  Automated parameter extraction for plucked string synthesis , 1997 .

[6]  Julius O. Smith,et al.  Extracting the fingering and the plucking points on a guitar string from a recording , 2001, Proceedings of the 2001 IEEE Workshop on the Applications of Signal Processing to Audio and Acoustics (Cat. No.01TH8575).

[7]  Mu-Huo Cheng,et al.  Automated analysis and computationally efficient synthesis of acoustic guitar strings and body , 1995, Proceedings of 1995 Workshop on Applications of Signal Processing to Audio and Accoustics.

[8]  Matti Karjalainen,et al.  Towards High-Quality Sound Synthesis of the Guitar and String Instruments , 1993, ICMC.

[9]  Neville H Fletcher,et al.  Nonlinear generation of missing modes on a vibrating string , 1984 .

[10]  Matti Karjalainen,et al.  Plucked-string models: From the Karplus-Strong algorithm to digital waveguides and beyond , 1998 .

[11]  Nicola Orio.  The Timbre Space of the Classical Guitar and Its Relationship with the Plucking Techniques , 1999, ICMC.

[12]  A. P. Speiser,et al.  The Physics of Musical Instruments. Von Neville H. Fletcher und Thomas D. Rossing, Springer-Verlag, Berlin, 1991, 620 Seiten, geb., DM 148,– , 1991 .

[13]  Vincenzo Lombardo,et al.  A Physical Model of the Classical Guitar, Including the Player's Touch , 1999, Computer Music Journal.

[14]  Caroline Traube,et al.  ESTIMATING THE PLUCKING POINT ON A GUITAR STRING , 2000 .

[15]  Margherita Pagani,et al.  Second Edition , 2004 .