Audio system phase equalization

摘要

A method is provided for optimizing acoustic localization at one or more listening positions in a listening environment such as, but not limited to, a vehicle passenger compartment. The method includes generating a sound field with a group of loudspeakers assigned to at least one of the listening positions, the group of loudspeakers including first and second loudspeakers, where each loudspeaker is connected to a respective audio channel; calculating filter coefficients for a phase equalization filter; configuring a phase response for the phase equalization filter such that binaural phase difference (Δφmn) at the at least one of the listening positions or a mean binaural phase difference (mΔφmn) averaged over the listening positions is reduced in a predefined frequency range; and filtering the audio channel connected to the second loudspeaker with the phase equalization filter.

主权项

1. A method for optimizing acoustic localization at least at one listening position in a listening environment, comprising:
generating a sound field by a group of loudspeakers assigned to the at least one listening position, where the group of loudspeakers includes a first and at least a second loudspeaker, and where each loudspeaker receives an audio signal from an audio channel; calculating filter coefficients of a phase equalization filter for at least the audio channel supplying the second loudspeaker, where a phase response of the phase equalization filter is configured such that a binaural phase difference (Δφmn) at the listening position or a mean binaural phase difference (mΔφmn)averaged over a plurality of listening positions is minimized in a predefined frequency range, the binaural phase differences being phase differences between the left and right ear of a listener at a respective listening position;= filtering the respective audio channel with the phase equalization filter; where the calculating of the filter coefficients of the phase equalization filter comprises performing a minimum search within an array of phase differences dependent on frequency and phase-shifts for at least one audio-channel, where the minimum search provides an optimum phase function φX,FILT(fm) indicative of an optimal phase shift (φX) as a function of frequency (fm), using the optimum phase function (φX,FILT(fm)) as a design target for calculating the filter coefficients of the phase equalization filter; smoothing the optimum phase function φX,FILT(fm) before calculating the phase response of the phase equalization filter; and performing the smoothing of the optimum phase function φX,FILT(fm) with a smoothing filter having a dynamic response that decreases as frequency increases.