Excitation Synthesis

For a further reduction in cost of implementation, particularly with respect to memory usage, it is possible to synthesize the excitation using a noise signal through a time-varying lowpass filter [440]. The synthesis replaces the recorded soundbard/enclosure sound. It turns out that the sound produced by tapping on a piano soundboard sounds very similar to noise which is lowpass-filtered such that the filter bandwidth contracts over time. This approach is especially effective when applied only to the high-frequency residual excitation after factoring out all long-ringing modes as biquads.

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About the Author: Julius Orion Smith III
Julius Smith's background is in electrical engineering (BS Rice 1975, PhD Stanford 1983). He is presently Professor of Music and Associate Professor (by courtesy) of Electrical Engineering at Stanford's Center for Computer Research in Music and Acoustics (CCRMA), teaching courses and pursuing research related to signal processing applied to music and audio systems. See http://ccrma.stanford.edu/~jos/ for details.