The Threshold of Hearing for Continuous and Interrupted Tones
Walter A. Rosenblith, George Armitage Miller · The Journal of the Acoustical Society of America · 1949
The quiet threshold of hearing for tones, as measured with earphones, shows large variations depending upon the method of presentation of the tones. When the tone is continuous the threshold may be much higher than when the tone is interrupted. This difference is especially marked at high frequencies. For both continuous and interrupted tones the thresholds were determined (1) by starting above threshold, and progressively decreasing the intensity, and (2) by starting below threshold and progressively increasing the intensity. With tones interrupted at slow rates the threshold for the descending series lies below the threshold for the ascending series. This is the usual result obtained with this method. However, when the tones are continuous the descending threshold may lie far above the ascending threshold depending upon the frequency, and the starting point for the descending series.