Real‐time guitar radiation sound synthesis of forced string and body eigenfrequency vibrations using microphone array techniques.

Abstract

A guitar top plate vibration is investigated for different frequency regions taking string driving point dependencies into consideration using a microphone array of 128 microphones and back‐propagating the recording to the top plate positions. These radiation patterns are integrated in space at arbitrary virtual microphone positions. A guitar tone or piece is then synthesized using these radiation patterns where the microphone positions can be changed as in a real recording situation. The synthesis process takes the pressure and phase relations of more than 100 positions on the top plate and the sound hole into consideration for two cases of waves, the traveling waves of forced top plate vibration of the string frequencies and the eigenfrequencies of the guitar body appearing mostly during the initial transient phase. These eigenfrequencies are integrated using the much more simple mode shapes of the top plate eigenmodes. The amplitude behavior of these frequencies, appearing and decaying during the initial transient, is calculated by integrating the energy which is supplied by the string acting with a force on the top plate as an impulse train.