Patent ID: 9118290
Filing Date: 2015-08-25
Classification: H03G,H04R

Abstract:
1. A system for automatic determination of at least one of equalization filter parameters or gain parameters used for equalization of audio signals reproduced in a vehicle, the system comprising: an audio amplifier configured to reproduce an audible test signal using at least one loudspeaker arranged in a passenger compartment of the vehicle so as to generate a corresponding acoustic test signal; at least one microphone arranged at an at least one desired listening position and configured to sequentially pick up the audible test signal as a measured test signal at different volume levels, as well as a noise signal at different non-acoustical measurement values representing a current state of the vehicle; a signal acquisition and processing system configured to receive the measured test signal and the noise signal, as well as the corresponding volume levels and non-acoustical measurement values, the signal acquisition and processing system being configured to: calculate power spectral density estimations, which depend on the volume levels and respectively, on the non-acoustical measurement values, of the measured test signal and the noise signal, respectively, calculate corresponding masking thresholds, which depend on the volume levels and, respectively on the non-acoustical measurement values, from the power spectral density estimations; calculate, for each pair of volume levels and non-acoustic measurement values, a target equalization curve, the target equalization curve being composed of non-negative values of a difference between a volume-dependent masking threshold calculated from a test signal power spectral density and a masking threshold calculated from a noise signal power spectral density, which depends on the non-acoustic measurement values; and calculate, for each pair of volume levels and non-acoustic measurement values, filter parameters of a parameterized filter prototype such that a filter magnitude response of the parameterized filter prototype approximates a corresponding target equalization curve.