Tuesday, June 3, 2008

Good vibrations...

On June 3, Apple was issued a patent related to simulation of the vibration of a string. This is likely related to a physical-model approach to sound generation for GarageBand or Logic virtual instruments. Such an approach can be superior to sample-based instruments, especially in terms of allowing user-adjustment of characteristics of the instrument and sound using a UI that has the appearance of an actual instrument. Physical modeling for sound generation is not new, of course, having been commercialized most successfully by Korg, Roland (e.g., V-Drums, V-Guitar lines), and others.

The unique aspect here appears to be that "the force acting on the string simulates a stream of a fluid medium flowing relative to the string"



United States Patent
7,381,881
Sapp
June 3, 2008
Simulation of string vibration
Abstract
A method of simulating a string using a wave equation relates movement of the string in time to force acting on the string, wherein the force acting on the string simulates a stream of a fluid medium flowing relative to the string. The simulated string is supported between two supports and is aligned at rest in a first direction between the two supports, a first of which allows movement in a second direction orthogonal to the first direction and a second of which does not allow movement. The string is then caused from rest to vibrate in a plane, which includes the first and second directions, by turbulence in the fluid flow causing the stream of fluid medium to exert a pressure on the string in the second direction. Movement of the string out of alignment with the first direction causes the stream of fluid medium flowing in the first direction to exert a force on the string in the second direction.



Claim 1. A method, comprising: simulating a string using a wave equation that relates movement of the string in time to force acting on the string, wherein the string has a longitudinal axis in a first direction and is moveable in a second direction orthogonal to the first direction, and the force acting on the string simulates a stream of a fluid medium flowing relative to the string in a direction having a component in a third direction orthogonal to both the first and second directions; and creating sounds using the wave equation.

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