The problem of designing a modal reverberator to match a measured room impulse response is considered. The modal reverberator architecture expresses a room impulse response as a parallel combination of resonant filters, with the pole locations determined by the room resonances and decay rates, and the zeros by the source and listener positions. Our method first estimates the pole positions in a frequency-domain process involving a series of constrained pole position optimizations in overlapping frequency bands. With the pole locations in hand, the zeros are fit to the measured impulse response using least squares. Example optimizations for a mediumsized room show a good match between the measured and modeled room responses.

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This paper introduces hexaphonic distortion as a way of achieving harmonically rich guitar distortion while minimizing intermodulation products regardless of playing style. The simulated hexaphonic distortion effect described in this paper attempts to reproduce the characteristics of hexaphonic distortion for use with ordinary electric guitars with mono pickups. The proposed approach uses a parallel comb filter structure that separates a mono guitar signal into its harmonic components. This simulates the six individual string signals obtained from a hexaphonic pickup. Each of the signals are then individually distorted with oversampling used to avoid aliasing artifacts. Starting with the baseline of the distorted mono signal, the simulated distortion produces fewer intermodulation products with a result approaching that of hexaphonic distortion.

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