A method for generating coefficients of a head-related impulse response, HRIR, filter usable in rendering audio for playback comprising: receiving parameters describing the location of a sound source, wherein the parameters are defined relative to the position of a head of a listener; determining a first set of filter coefficients from a spherical head model in response to at least one of the parameters; determining a second set of filter coefficients from a pinna model in response to at least one of the parameters, wherein the pinna model includes a front/back asymmetry model to account for a pinna shadowing effect; determining a third set of filter coefficients from a torso model in response to at least one of the parameters; determining a fourth set of coefficients from a near-field model in response to at least one of the parameters; and combining the first, second, third, and fourth sets of coefficients by convolution to generate the coefficients of the HRIR filter, wherein determining the second set of filter coefficients comprises: computing, for each ear, a front/back difference for front elevations in front of the head and a front/back difference for back elevations behind the head, from a difference between responses for respective directions that are mirror images of each other, mirrored at a frontal plane, wherein a tilt factor specifies how much of the difference is applied to the front/back difference for the front elevations to boost the front elevations and how much of the of the difference is applied to the front/back difference for the back elevations as a level cut to the back elevations, wherein the difference is a function of azimuth and elevation; and computing front/back difference filters for the front and back elevations from the front/back differences for the front and back elevations, respectively. receiving parameters describing the location of a sound source, wherein the parameters are defined relative to the position of a head of a listener; determining a first set of filter coefficients from a spherical head model in response to at least one of the parameters; determining a second set of filter coefficients from a pinna model in response to at least one of the parameters, wherein the pinna model includes a front/back asymmetry model to account for a pinna shadowing effect; determining a third set of filter coefficients from a torso model in response to at least one of the parameters; determining a fourth set of coefficients from a near-field model in response to at least one of the parameters; and combining the first, second, third, and fourth sets of coefficients by convolution to generate the coefficients of the HRIR filter, wherein determining the second set of filter coefficients comprises: computing, for each ear, a front/back difference for front elevations in front of the head and a front/back difference for back elevations behind the head, from a difference between responses for respective directions that are mirror images of each other, mirrored at a frontal plane, wherein a tilt factor specifies how much of the difference is applied to the front/back difference for the front elevations to boost the front elevations and how much of the of the difference is applied to the front/back difference for the back elevations as a level cut to the back elevations, wherein the difference is a function of azimuth and elevation; and computing front/back difference filters for the front and back elevations from the front/back differences for the front and back elevations, respectively. computing, for each ear, a front/back difference for front elevations in front of the head and a front/back difference for back elevations behind the head, from a difference between responses for respective directions that are mirror images of each other, mirrored at a frontal plane, wherein a tilt factor specifies how much of the difference is applied to the front/back difference for the front elevations to boost the front elevations and how much of the of the difference is applied to the front/back difference for the back elevations as a level cut to the back elevations, wherein the difference is a function of azimuth and elevation; and computing front/back difference filters for the front and back elevations from the front/back differences for the front and back elevations, respectively.