Ambiophonic principles for the recording and reproduction of surround sound for music

This paper discusses the psychoacoustical background and the computational issues involved in the real-time implementation of a complete Ambiophonics reproduction system based on binaural technology. Ambiophonics, which requires only two media channels, evolved from previously known approaches such as the reproduction of binaural recordings over closely spaced loudspeakers through cross-talk cancellation, and the reconstruction of hall ambience by convolution from suitable impulse responses. The equations for the design of the digital filter coefficients are derived with regard to the many possible kinds of pre-existing recordings (binaural, sphere, ORTF, M/S), and their implementation on available hardware and software platforms are described. The authors suggest psychoacoustic explanations for the perceived audible performance, and describe the first results of a comparative listening test, evaluating the realism of three periphonic surround reproduction systems: Stereo Dipole, Ambisonics and Ambiophonics.