Measurements of time-invariant not linearity in musical instruments

The virtual reconstruction of sound properties of musical instruments could be obtained starting from the measurements of impulse responses of the sound chests of violins and violas or the bore of trumpets and flutes. Convolving the sound signals of the player captured just after his performance and before the body of the instruments, the final effect of the musician can be reconstructed. However only the linear components of the body could be reproduced, whereas all not linearity is not taken into account. In this paper a novel technique for measuring and reproducing not-linear sound characteristics of musical instruments is presented. The method has been applied to capture both acoustic (pressure) and vibration (body’s particle velocity) impulse responses. The new method, starting from Volterra Kernel expression of not-linearity, has been applied to few wind instruments up to 5th order of distortion. The intensity of acoustic radiation has been measured and the influence of not-linearity has been evaluated in sound reconstruction and compared with previous methods.