Patent ID: 8320581

Claim:
A method comprising: in a vehicle engine harmonic enhancement system, providing a first engine harmonic signal, comprising providing harmonics of a fundamental harmonic frequency; providing a first set of harmonics of the fundamental harmonic frequency; separately equalizing each of the first set of harmonics of the fundamental harmonic frequency to provide equalized harmonics so that at least one of the equalized harmonics has a different equalization that at least one of the other equalized harmonics; providing a second set of harmonics of the fundamental harmonic frequency; and separately equalizing each of the second set of harmonics of the fundamental harmonic frequency, wherein the equalizing the first engine harmonic enhancement audio signal comprises equalizing the first engine harmonic enhancement audio signal to provide a first equalized engine harmonic enhancement signal and transducing the first engine harmonic enhancement audio signal so that the apparent source of the transduced first sound enhancement audio signal is a first vehicle location; and wherein the equalizing the second engine harmonic enhancement audio signal comprises equalizing the second engine harmonic enhancement audio signal to provide a second equalized engine harmonic enhancement signal so that the second equalized engine harmonic enhancement signal has a different equalization than the first equalized engine harmonic signal; and transducing the second engine harmonic enhancement audio signal so that the second apparent source of the transduced second sound enhancement audio signal is a second vehicle location.