Time-Aligned Spatial Upsampling of Spherical Microphone Array Recordings

With the Spherical Array Interpolation by Time Alignment (SARITA) method, the authors introduced an approach for spatial upsampling of spherical microphone array (SMA) signals (T. Lübeck, J. M. Arend, and C. Pörschmann, IEEE/ACM Transactions on Audio, Speech, and Language Processing, vol. 31, pp. 1163-1174 [2023]). The basic idea of this method is to perform the interpolation after time-aligning adjacent microphone signals. The upsampled SMA signals can be represented as spherical harmonic coefficients of much higher spatial order than is possible with the sparsely measured signals. Instead of impulse responses, the method is now applied to SMA recordings. Binaural decoding of upsampled SMA recordings is compared technically and perceptually to a baseline Ambisonics decoding. The results show that the SARITA method can also be applied to low-order array recordings and significantly improves their binaural reproduction.