A moving ripple sound is a broadband, complex sound with a sinusoidal spectral profile that drifts along the logarithmic frequency axis at constant velocity. Each image below shows the spectrotemporal (frequency content vs. time) plot for one moving ripple sound. The colors represent signal power, with red the maximum.
Row one: temporal frequency of either 8 or 12 Hz. Row two: spectral frequency of either 1 or 0.3 cycles/octave. Row Three: Frequency band of three octaves, going upward either from 202 or 236 Hz.Click the speaker icon to hear the associated moving ripple sound (requires wav plugin). Listen for differences as each parameter is varied. In our experiments on auditory short-term memory, our stimuli were allowed to vary in temporal frequency.