Experiments that were designed to investigate the properties of a peculiar type of distortion that has been observed in the cochlea at high excitation intensities are described. The pairs consist of two components with frequencies that are equally spaced about one-half the excitation frequency and that sum to the excitation frequency. Pairs centered on odd-harmonics of one-half the excitation frequency were also observed. The pairs exhibit a threshold of appearance, their frequencies can drift with time, and at excitation intensities well above threshold the pairs develop into noisy bands instead of remaining as discrete frequency components. Distortion pairs with similar properties were observed in five different species of the order Rodentia. An analogy between the behavior of the pairs with increasing excitation intensity and the development of turbulence in the boundary layer over a flat plate is discussed. The turbulence arises from an instability in the flow, and it is suggested that the cochlear distortion pairs develop from a similar instability in the cochlear flow.
ASJC Scopus subject areas
- Arts and Humanities (miscellaneous)
- Acoustics and Ultrasonics