Index of content:
Volume 103, Issue 3, March 1998
- SELECTED RESEARCH ARTICLES 
The solution for the propagation of sound in a toroidal waveguide with driven walls (the acoustitron)103(1998); http://dx.doi.org/10.1121/1.423231View Description Hide Description
This paper describes the theory of sound propagation in a toroidal waveguide with driven walls. This configuration has the advantage of simulating a tube of infinite length. The general solution for the velocity potential is derived in terms of an arbitrary function which represents the angular dependence of the disturbance of the driving wall. Two different cases are considered. The first is a toroid with the wall driven at a single angular position. The second case is a toroid with walls driven such that a traveling wave is generated in the wall with a controllable wave number and frequency. A traveling wave is produced inside the toroid when the circumference of the toroid is a whole number of wavelengths for the wave in the wall. The amplitude of the traveling wave is a function of the intrinsic speed of sound in the medium inside the toroid. A device we call an acoustitron was constructed to verify the results of the latter case. Experimental results agree well with those predicted by theory.
103(1998); http://dx.doi.org/10.1121/1.423232View Description Hide Description
A model of pitch perception is presented involving an array of delay lines and inhibitory gating neurons. In response to a periodic sound, a minimum appears in the pattern of outputs of the inhibitory neurons at a lag equal to the period of the sound. The position of this minimum is the cue to pitch. The model is similar to the autocorrelation model of pitch, multiplication being replaced by an operation similar to subtraction, and maxima by minima. The two models account for a wide class of pitch phenomena in very much the same way. The principal goal of this paper is to demonstrate this fact. Several features of the cancellation model may be to its advantage: it is closely related to the operation of harmonic cancellation that can account for segregation of concurrent harmonic stimuli, it can be generalized to explain the perception of multiple pitches, and it shows a greater degree of sensitivity to phase than autocorrelation, which may allow it to explain certain phenomena that autocorrelation cannot account for.