Post date: 03-oct-2014 5:44:43
Title: Filter design in a superdirective array of phase shift
Date: 07-oct-2014
Materials: slides pdf
Speaker: Marcos F. Simón Gálvez. University of Southampton, United Kingdom
Authors: Marcos F. Simón Gálvez, Stepehn J. Elliot, and Jordan Cheer
Institute of Sound and Vibration Research, University of Southampton, SO17 1BJ, UK.
Abstract:
Traditionally, the design of filters for personal audio systems employing loudspeaker arrays has been based on a frequency domain optimisation, and the time domain filter responses are then obtained by inverse Fourier transformation of the optimised frequency responses. Since the responses of the filters are optimised frequency by frequency using this method, there is no constraint on the causality of the filters. By posing the filter optimisation problem in the time domain, the filter responses will be causally constrained and the optimisation need only be performed once, for all frequencies. This study presents a formulation of the time domain filter optimisation method for superdirective beamforming, using either the acoustic contrast maximisation or the least squares inverse techniques. Simulations and experimental results show the effectiveness of the method and compare the performance that can be obtained with both the time domain optimised control techniques and the equivalent frequency domain design methods. The results show how for short filter lengths, the filters designed in the time domain perform better.