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In a paper in this journal, a framework was presented wherein a number of practical methods for finding the perceptually most important sinusoids in audio signals could be related using a particular perceptually motivated distortion measure, and it was argued that for Gaussian noise and a large number of samples, these methods should attain the Cramer-Rao lower bound. In this correspondence, we report some new results on this subject. Specifically, we analyze the finite-sample performance of these methods in experiments, and we conclude that for a high number of samples, they perform close to the Cramer-Rao lower bound. However, for a low number of observations, we demonstrate that special care must be taken in designing the perceptually motivated distortion measure if high-resolution estimates are desired. In particular, the smoothness of the frequency response of the perceptual filter that implements the distortion measure is shown to be important.

Acoustic feedback is a well-known problem in hearing aids, which is caused by the undesired acoustic coupling between the loudspeaker and the microphone. Acoustic feedback limits the maximum amplification that can be used in the hearing aid without making it unstable. The goal of adaptive feedback cancellation (AFC) is to adaptively model the feedback path and estimate the feedback signal, which is then subtracted from the microphone signal. The main problem in identifying the feedback path model is the correlation between the near-end signal and the loudspeaker signal, which is caused by the closed signal loop. A possible solution to this problem is to use the prediction error method (PEM)-based AFC with a linear prediction (LP) model for the near-end signal. In this paper, a modification to the PEM-based AFC is presented where the LP model is replaced by a sinusoidal near-end signal model. More specifically, it is shown that using frequency estimation techniques to estimate the sinusoidal near-end signal model improves the performance of the PEM-based AFC compared to using a LP model. Simulation results for a hearing aid scenario indicate a significant improvement in terms of misadjustment and maximum stable gain increase.