Patent ID: 7949141
Filing Date: 2011-05-24
Classification: G10H,G10K,H04S

Abstract:
1. An apparatus to process a plurality of input audio signals comprising: a plurality of input terminals to accept a plurality of input signals; a multi-input, multi-output reverberator accepting the plurality of input signals and arranged to generate a set of output signals, each reverberator output signal corresponding to a direction of sound arrival in a listening environment and including delayed echo components simulating the echoes a listener is likely to hear from the corresponding direction in the listening environment, such that each input to the multi-input, multi-output reverberator generates a plurality of outputs corresponding to a plurality of directions of sound arrival; and a multi-input, two-output filter with inputs coupled to the outputs of the reverberator, the inputs further coupled to the plurality of input terminals, one filter output for the left ear and one filter output for the right ear, the filter arranged to implement a number of head related transfer function (HRTF) filter pairs, each HRTF filter pair corresponding to an HRTF direction of arrival of sound in a listening environment, the two outputs playable through headphones, each HRTF filter pair including a left ear HRTF filter and a right ear HRTF filter, the sum of the left ear HRTF filter outputs forming the left ear output, and the sum of the right ear HRTF filter outputs forming the right ear output of the multi-input, two-output filter, wherein the reverberator includes a plurality of feedback signal paths, one for each HRTF direction for the listener, such that the coupling of the reverberator outputs to the multi-input, two-output filter couples each of the feedback signal paths to both the left ear HRTF filter and the right ear HRTF filter of a corresponding pair of the HRTF filter pairs, and wherein the reverberator further includes a multi-input, multi-output mixer with inputs coupled to the input terminals and to the outputs of the feedback signal paths, the mixer arranged to mix the plurality of inputs, the mixer outputs coupled to the feedback signal paths, the mixing describable by a non-diagonal matrix, such that at least one mixer output is generated by combining a plurality of mixer inputs, such that each direct sound corresponding to an input and every separate echo generated by a corresponding reverberator output is processed by both HRTF filters of one pair of the HRTF filter pairs such that each reverberator output is associated with a corresponding binaurally rendered direction of sound arrival, such that the listener listening to the left and right output signals in the listening environment through headphones has the sensation of listening to the plurality of input audio signals as if they are emanating from a plurality of loudspeakers spatially located at the loudspeaker locations in the listening environment.