A Review of Cardioid Type Unidirectional Microphones
Ralph P. Glover · The Journal of the Acoustical Society of America · 1940
The generalized characteristics of a unidirectional microphone whose response pattern is a cardioid of revolution are discussed with regard to pickup of reverberant energy, directional discrimination, and effect of distance and sphericity of wave on response frequency characteristic. Comparisons with the performance of the nondirectional pressure microphone and velocity microphone are made. Previous two-transducer structure for obtaining the cardioid characteristic are reviewed and a new single-transducer structure operating by acoustical phase shift is described.