Paralleling the extensive study of the artistic use of the vocal and instrumental vibrato is this study in the perception of the vocal vibrato. By using a synthetic tone-mixer, variations in pitch and intensity deviations, both as to rate and extent, were produced for the observers who responded by several methods - production, comparison and estimate. The data indicate that the observers, all of whom possess high musical discrimination for pitch and intensity, hear the deviations in pitch extent as about one-third the actual amount, that different rates of oscillation near the average of artistic usage, have little significant effect upon the perceived extent. The study is intensive rather than extensive. Some illusory effects are noted. The relation to musical sonance is discussed
