The masking of speech.

Abstract

Auditory masking is defined as "the shaft of the threshold of audibility of the masked sound due to the presence of the masking sound." Sounds are classified as noises, tones and voices. For all 3, the stimulus-dimensions determining masking are the intensity, the frequency or spectrum, and the temporal pattern of the sound. Masking depends primarily on the speech-to-noise ratio over the range of frequencies involved in speech. Sounds of low frequency mask this range more effectively than sounds of high frequency. Interruptions in the sound decrease the masking effectiveness. Annoyance also increases as the intensity is raised, but low-frequency sounds are less annoying than high-frequency sounds, and intermittent, irregular sounds are more annoying than continuous sounds. There is no evidence that annoyance interferes with vocal communications in the laboratory situation.