Body Resonator

Figure 39: Measured body response from a gypsy guitar. The plot shows the signal from time 0 to $50$ ms.

Figure 40: Measured body response from a gypsy guitar. The plot shows the signal from time 0 to $1$ s.

Figure 41: Measured body admittance from a gypsy guitar. The plot shows both the magnitude and phase at frequencies between $50$ Hz to $500$ Hz.

Figure 42: Measured body admittance from a gypsy guitar. The plot shows both the magnitude and phase at frequencies between $50$ Hz to $2000$ Hz.

From our synthesis model, the body resonator has a driving-point admittance that filters the output of the string model to transform force waves along the string into acceleration waves at the bridge [44]. Taking the inverse-FFT of the measured driving-point admittance, we obtain the impulse response of the body of the instrument. This time-domain signal can be stored as a wavetable for convolution with the output of the synthesis string-model. Figures 39, 40, 41 and 42 show the time-domain signal and spectrum (both magnitude and phase) of a measured guitar's body impulse response, respectively. As shown, the impulse response lasts well over $50$ ms long. Viewing its spectrum in Figure 41, we note peaks that occur near $120$ and $250$ Hz.