Appendix A: Known Patents

Disclaimer: The information in this section is based on the author's understanding at the time of this writing, but it is not necessarily correct or useful for any legal purposes. For legally relevant opinions and information, please consult an attorney.

The Karplus-Strong patents^D.27 are believed to be expired (at least the U.S. patent), and the Extended Karplus-Strong additions [213,437] were never patented in the first place. Similarly, the guitar-distortion and amplifier-feedback techniques published in [502] were not patented as far as we know.^D.28Thus, there are no known patents (to the author) pertaining to the electric guitar and associated effects described in this appendix.

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written by 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.