| An ascending tone is interrupted by a noise burst, but is perceptually continuous. |
The illusory continuity of tones is the auditory illusion caused when a tone is interrupted for a short time (approximately 50ms or less), during which a narrow band of noise is played. Whether the tone is of constant, rising or decreasing pitch, the ear perceives the tone as continuous if the 50ms (or less) discontinuity is masked by noise. Because the human ear is very sensitive to sudden changes, however, it is necessary for the success of the illusion that the amplitude of the tone in the region of the discontinuity not decrease or increase too abruptly.