Perception of pitch and roughness in vocal signals with subharmonics

Pitch and roughness were rated according to the extent of amplitude modulat ion (AM) and frequency modulation (FM) of a subharmonic [fundamental freque ncy (F-0)/2]. The objective was to determine the identification boundaries for pitch and roughness and to discover how both kinds of modulation affect these boundaries. Another objective was to judge the reliability between s ubjects when identifying subharmonic-related pitch and roughness. Three pro cedures were used: ABX comparisons, method of adjustment, and rating of rou ghness. Results indicated that the crossover point to the lower pitch (asso ciated with the subharmonic) occurred between 10% and 30% modulation, depen ding on modulation type and F-0. Subjects demonstrated highly variable perc eptions of pitch and roughness, with poor intersubject reliability.