Database of musical instruments directivity pattern

Abstract

The directivity pattern of an acoustic source describes the manner in which the sound radiates from it in the spatial domain. It may be used in virtual reality applications to improve the sense of realism perceived by the user. This work presents a directivity pattern database of 41 historical and modern orchestral instruments. The generation of this database includes the recording session in an anechoic chamber using a surrounding spherical microphone array, followed by a preliminary stage of isolating steady parts from the raw signals. Then, calibration is applied by normalizing the signals with the electrical channel gains and with the microphone gains. The fundamental frequency and overtones are then detected and the energy at each harmonic is saved for each played tone. Source centralization is applied in order to align the acoustic center of the sound source to the physical center of the microphone array. Last, a directivity pattern is generated in the spherical harmonics domain for each third-octave band by averaging the directivity pattern at all the overtones with a frequency belongs to that band.