Spatial processing stereo system
View Patent ↗A spatial processing stereo system (“SPSS”) that receives audio signals and a limited number of user input parameters associated with the spatial attributes of a room, such as “room size”, “stage distance”, and “stage width”. The input parameters are used to define a listening room and generate coefficients, room impulse responses, and scaling factors that are used generate additional surround signals.
1. A spatial processing stereo system (SPSS), comprising:
a plurality of filters for filtering a left audio signal and a right audio signal;
a room response generator;
a user interface for entry of parameters associated with the spatial attributes of a room;
a user response processor that receives the parameters from the user interface and generates coefficients that are used by at least one of the plurality of filters and being in receipt of a room impulse response that is also used by at least one of the plurality of filters; and
at least two additional audio signals that are generated with filters that use the coefficients filtering the left audio signal and right audio signal with a signal processor that receives at least the right audio and the left audio signal and generates at least a left signal, a first left surround signal, a right signal and a first right surround signal with a coefficient matrix using the coefficients where the signal processor includes a pair of shelving filters and a pair of delay lines and generates at least a second left surround signal and a second right surround signal.
2. The SPSS of claim 1 , where the signal processor includes a fast convolution processor that generates a third left surround signal and a third right surround signal using at least one of the coefficients.
3. The SPSS of claim 2 , where the first left surround signal is combined with the second left surround signal and third left surround signal and the first right surround signal is combined with, the second right surround signal and third right surround signal and results in the left surround signal output and the right surround signal output.
4. The SPSS of claim 2 , where the fast convolution processor, further includes a decimation filter that reduces the sample rate of the left audio signal and the right audio signal as a combined audio signal, and is coupled to at least a pair of all-pass filters to generate the third left surround signal and the third right surround signal.
5. The SPSS of claim 4 , where the fast convolution processor further includes a two by two matrix having the left surround signal and the right surround signal at the input and generating a left back surround signal and aright back surround signal.
6. The SPSS of claim 1 , where a plurality of delay parameters are used with the shelving filter that result in delayed signals, where the delayed signals are the left surround signal and the right surround signal.
7. The SPSS of claim 1 , where the coefficient matrix further includes a variable matrix used with the left audio signal and right audio signal to generate the first left signal and the first right.
8. The SPSS of claim 7 , where the coefficient matrix further includes a fixed matrix used with the left audio signal and right audio signal to generate a left surround signal and right surround signal.
9. The SPSS of claim 8 , where a scaling factor associated with a stage width, parameter that is one of the spatial attributes of the room is applied to the first right signal, first left signal, left surround signal, and right surround signal.
10. The SPSS of claim 1 , where the room response generator further includes a M band filter bank, where the shelving filter receives the element-wise product of a first random noise input and a lowpass filtered second random noise input and an output of the shelving filter is processed by the M-band filter bank in order to generate the room impulse response.
11. A method for spatial processing in a spatial processing stereo system (SPSS), comprising:
receiving parameters at a user interface associated with spatial attributes of a room;
filtering a left audio signal and a right audio signal with a plurality of filters;
generating with a room response generator having a user response processor that receives the parameters from the user interface, coefficients that are used by at least one of the plurality of filters that is in receipt of a room impulse response; and
processing the left audio signal and right audio signal with the at least one of the plurality of filters to generate at least two other surround audio signals with a processor that receives at least the right audio signal and the left audio signal and generates at least a left signal, a first left surround signal, a first right surround signal with a coefficient matrix using the coefficients where the signal processor includes a pair of shelving filters and a pair of delay lines and at least a second left surround signal and a second right surround signal.
12. The method of spatial processing of claim 11 , further includes determining the room impulse response with the room response generator with at least one of the parameters that is an input room size parameter and is associated with a room size spatial attribute.
13. The method of spatial processing of claim 11 , further including determining a plurality of coefficients to scale the amplitudes of the delayed left audio signal and right audio signals from at least one of the parameters associated with the spatial attribute of a stage distance.
14. The method of spatial processing of claim 13 , includes generating the second left surround signal and the second right surround signal with a shelving filters that use delay amplitude scale coefficients.
15. The method of spatial processing of claim 11 , further includes generating a second left surround signal and a second right surround signal by filtering a combined left audio signal and right audio signal with a decimation filter and an all-pass filter.
16. The method of spatial processing of claim 11 , further includes determining a plurality of scale factors from at least one of the parameters which is associated with a stage width spatial attributes.
17. The method of spatial processing of claim 16 , includes generating a center audio signal with a signal combiner that uses a scale factor.
18. The method of spatial processing of claim 11 , where the generating the at least two other audio signals occurs in a digital signal, processor (DSP).
19. The method of spatial processing of claim 11 , including generating a center audio signal from the right audio signal and left audio signal.
20. A spatial processing stereo system (SPSS), comprising:
a plurality of filters for filtering a left audio signal and a right audio signal;
a room response generator;
a user interface for entry of parameters associated with spatial attributes that include a room size spatial attribute, a stage width spatial attribute and a stage distance spatial attribute;
a user response processor that receives the parameters from the user interface and generates coefficients that are used by at least one of the plurality of filters;
a room response generator that determines the room impulse response for the room size spatial attribute, where the impulse response is used by at least one of the plurality of filters; and
at least two additional, audio signals that are generated with filters that use the coefficients with the left audio signal and right audio signal.
21. The SPSS of claim 20 , further includes generation of a center audio signal from the left audio signal and right audio signal, where the generation of the center audio signal uses the parameter associated with the stage distance spatial attribute.
22. A spatial processing stereo system (SPSS), comprising:
a plurality of filters for filtering a left audio signal and a right audio signal;
a room response generator;
a user interface for entry of parameters associated with spatial attributes of a room;
a signal processor that receives at least the right audio signal and the left audio signal and generates at least a left signal and right signal and center signal with a coefficient matrix using the coefficients generated from at least one of the parameters and a shelving filter that receives delay amplitude scale coefficients derived from at least one of the parameters and generates at least a first left surround signal and a first right surround signal;
a user response processor that receives the parameters from the user interface and generates coefficients that are used by at least one of the plurality of filters and being in receipt of a room impulse response that is also used by at least one of the plurality of filters; and
at least two additional audio signals that are generated with filters that use the coefficients filtering the left audio signal and right audio signal and where the signal processor includes a fast convolution processor that generates a second left surround signal and a second right surround signal using at least one of the parameters.