RECORDING, SIMULATION AND REPRODUCTION OF SPATIAL SOUNDFIELDS BY SPATIAL PCM SAMPLING (SPS) Reference PACS: 43.60.Fg. 43.38.Hz

A new method for recording the spatial properties of a soundfield, or for generating a synthetic three-dimensional soundfield, is described. The spatial distribution of sound waves passing at a point in space is sampled by means of a number of virtual super-directive microphones, covering almost uniformly the surface of a sphere. This corresponds to a discretization of the spatial information, which is exactly the spatial equivalent of the PCM sampling of a waveform. Continuing the comparison, traditional High Order Ambisonics can instead be seen as the correspondent of the Fourier transform of a periodic waveform, representing the spatial distribution of sound as the superposition of a number of spatial frequencies (the spherical harmonics). As with waveforms, the PCM model is generally more versatile and less constrained than the corresponding frequency-domain representation. Although some operations are easier in frequency domain, others are easier in the original PCM domain. When dealing with spatial information, modifications of the sound field, such as rotation, stretching (zooming), and emulating sound effects such as reverb, shielding