Subaudible tones and the pulsation threshold procedure

Abstract

A pulsing, audible maskee at a low sensation level appears to stay on continuously when the interruptions are filled by a pulsed masker at a different frequency. The perceptual continuity of the maskee changes to discontinuity when its intensity is raised above its “pulsation threshold.” In this study, an additional tone with the same frequency as the maskee (800 Hz) was presented with the masker (500 Hz). The added tone had the effect of raising the pulsation threshold only when this tone was presented above its masked threshold. Thus the pulsation threshold procedure cannot be used to detect the presence of a masked subaudible tone. An important implication is that contrary to recent applications the existence and characteristics of inaudible subjective tones cannot be studied with this method. [Work supported by NIH and the Department of Otorhinolaryngology, University of Michigan Medical School.]