Improved Quasi-Stereophony and “Colorless” Artificial Reverberation
Manfred R. Schroeder · The Journal of the Acoustical Society of America · 1961
“Quasi stereophony” is defined as the reproduction over two or more loudspeakers (or binaural earphones) of different sound signals derived from a single audio signal. The purpose of quasi-stereophony is to create (from a single audio signal) an illusion of spatially distributed sound sources. Quasi-stereophonic reproduction does not permit correct localization but does share with true stereophony the properties of “depth” and “ambience” which are important attributes of stereophony (for the casual listener perhaps even more important than correct localization). This paper describes a new filtering method for producing quasi-stereophony. In contrast to earlier proposals, the new filtering method leaves the amplitude spectrum of the sound intact. The same kind of filter has also been used for generating “colorless” artificial reverberation. Experimental results indicate that both quasi-stereophony and artificial reverberation can be achieved without spectral distortion.