A method for synthesizing sound includes receiving one or more first inputs (80), each including a respective monaural audio track (82). One or more second inputs are received, indicating respective three-dimensional (3D) source locations having azimuth and elevation coordinates to be associated with the first inputs. Each of the first inputs is assigned respective left and right filter responses based on filter response functions that depend upon the azimuth and elevation coordinates of the respective 3D source locations. Left and right stereo output signals (94) are synthesized by applying the respective left and right filter responses to the first inputs.