The perception of microsound and its musical implications

Sound particles or microsounds last only a few milliseconds, near the threshold of auditory perception. We can easily analyze the physical properties of sound particles either individually or in masses. However, correlating these properties with human perception remains complicated. One cannot speak of a single time frame, or a "time constant" for the auditory system. The hearing mechanism involves many different agents, each of which operates on its own timescale. The signals being sent by diverse hearing agents are integrated by the brain into a coherent auditory picture. The pioneer of "sound quanta," Dennis Gabor (1900-1979), suggested that at least two mechanisms are at work in microevent detection: one that isolates events, and another that ascertains their pitch. Human hearing imposes a certain minimum duration in order to establish a firm sense of pitch, amplitude, and timbre. This paper traces disparate strands of literature on the topic and summarizes their meaning. Specifically, we examine the perception of intensity and pitch of microsounds, the phenomena of tone fusion and fission, temporal auditory acuity, and preattentive perception. The final section examines the musical implications of microsonic analysis, synthesis, and transformation.