Multiple-point Statistical Room Correction for Audio Reproduction: Minimum Mean Square Error Correction Filtering.

Fredrik Lingvall, Wavetrain AS and Lars-Johan Brännmark

Journal of the Acoustical Society of America, vol. 125, no. 4, April 2009, pp. 2121-2128.

Abstract:

This paper treats the problem of correction of loudspeaker and room responses using a single source. The objective is to obtain a linear correction filter, which is robust with respect to listener movement within a predefined region-of-interest. The correction filter is based on estimated impulse responses, obtained at several positions, and a linear minimum mean squared error criteria.

The impulse responses are estimated using a Bayesian approach that takes both model errors and measurement noise into account, which results in reliable impulse response estimates and a measure of the estimation errors.

The correction filter is then constructed by using information from both the estimated impulse response coefficients and their associated estimation errors. Furthermore, in the optimization criteria a time-dependent reflection filter is introduced, which attenuates the high frequency parts of the reflected responses, that is, the parts of the responses that cannot be compensated with a single source system.

The resulting correction filter is shown to significantly improve both the temporal and spectral properties of the responses compared to the uncorrected system, and, furthermore, the obtained correction filter has a low level of pre-ringing.

Related publications:

PhD Thesis by Lars-Johan Brännmark

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