Contents: 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 | 2014 | 2013 | 2012 | 2011 | 2010 | 2009 | 2008 | 2007 | 2006 | 2005 | 2004 | 2003 | 2002 | 2001

2008, 17

Varsha Shah, Rekha S. Patil

Virtual piano using inharmonic dispersion tunable comb filter

language: English

received 25.08.2008, published 14.11.2008

Download article (PDF, 122 kb, ZIP), use browser command "Save Target As..."
To read this document you need Adobe Acrobat © Reader software, which is simple to use and available at no cost. Use version 4.0 or higher. You can download software from Adobe site (


An excitation/filter system of inharmonic sound synthesis signal is presented with an application to piano, a stiff string instrument. Specific features of the piano string important in wave propagation, dispersion due to stiffness, frequency dependent losses, presence of phantom partials and thump noise are included in the proposed model. The modified narrow bandpass filter is used as a basic building block in modeling the vibrating structure. The parallel banks of narrow band pass filters known as Inharmonic Dispersion Tunable Comb filter is used to model the dispersion. The center frequencies of narrow bandpass filters can be tuned to follow the same relation as the partial frequencies of piano tone. Novel loss filter is designed to implement frequency dependent losses. The resulting model is simulated using MATLAB which works as a Virtual Piano.

Keywords: bandpass, bandstop, dispersion, inharmonicity, synthesis

7 pages, 7 figures

Сitation: Varsha Shah, Rekha S.Patil. Virtual piano using inharmonic dispersion tunable comb filter. Electronic Journal “Technical Acoustics”,, 2008, 17.


1. H. Fletcher, T. Rossing. The Physics of Musical Instruments, Berlin. Germany: Springer-Verlag, 1991.
2. H. Fletcher. Normal Vibration Frequencies of a stiff piano string. J. Acoust. Soc. Amer., vol. 3, pp. 203-209, 1964.
3. Kirk R. E. Tuning preferences for piano unison groups. J. Acoust. Soc. Amer., 31 pp. 1644-1648, 1959.
4. Balaz Bank, Laszlo Sujbert. A Piano model including longitudinal string vibrations. In Proc. 7th Int. Conf. Digital Audio Effects, October 2004, pp.89-94
5. S. K. Mitra. Digital Signal Processing. The McGraw Hill.
6. Balázs Bank and Vesa Välimäki. Robust Loss Filter Design for Digital waveguide Synthesis of String Tones. IEEE Signal Processing Letters, vol. 10, January 2003.
7. H. Fletcher, E. D. Blackham, R. Stratton. Quality of piano tones. J. Acoust. Soc. Amer., vol. 34, no. 6, pp. 749-761, 1962.
8. J. Chowning. The synthesis of complex audio spectra by means of frequency modulation. Journal of the Audio Engineering Society, vol. 21, no. 7, pp. 526-534, Sept. 1973.
9. Jean Laroche, Jean Louis Meillier. Multichannel Excitation /Filter Modeling of Percussive Sounds with Application to the Piano. IEEE Tran. on Speech and Audio Processing, vol.2, no. 2, pp 329-344, April 1994.
10. J. Rauhala, H.-M. Lehtonen, V. Välimäki. Multi-ripple Loss Filter for waveguide Piano Synthesis. in Proc. Int. Computer Music Conf., Barcelona, Spain, pp. 729-732, September 2005.
11. Julien Bensa, Kristoffer Jensen, Richard Kronald-Martinet. A Hybrid Resynthesis Model For Hammer String Interaction of Piano Tones. EURASIP Journal on Applied Signal Processing, pp 1021-1035, 2004.
12. S. C. Pei, C. C. Tseng. IIR multiple notch filter design based on allpass filter, IEEE Transactions on Circuits and Systems, vol. 44, No. 2, pp. 133-136, Feb. 1997.
13. Smith J. O., Van Duyne S. A. Commuted piano synthesis. Proc. Int. Computer Music Conf., 1995, pp. 319-326.
14. J. Rauhala, V. Välimäki. Tunable dispersion filter design for piano synthesis. IEEE Sig. Proc. Letters, vol. 13, no. 5, pp. 253-256, 2006.
15. Ashok Ambaradar. Analog And Digital Signal Processing, Thomson, 1999.


Varsha Shah - M.E., Pursuing Ph.D. Working as Asst. Professor at Rizvi College of Engineering, University of Mumbai, India.

e-mail: varsha_shah_1(at)


Rekha S. Patil - M.E., Ph.D., Presently working as a Principal, D.Y.Patil College of Engineering, Talsande, Kolhapur, India. Has been in the teaching profession since last 35 years at Udergraduate and post graduate level. Has held various posts such as Head of the Department, Dean of academics, Principal. Has guided more than 40 students for M.E. dissertation. Currently 7 students are doing Ph.D. under her guidance. Has published more than 35 papers at national, international level conferences and journals.

e-mail: prekha46(at)