Abstract: A method of generating a desired shelving filter for audio data, the desired shelving filter having a low-corner frequency U and a high-corner frequency f2, wherein the difference between the gain of the frequency response of the desired shelving filter at f2 and the gain of the frequency response of the desired shelving filter at U is substantially equal to a non-zero desired amount, the method comprising: determining an order for a first shelving filter of a first predetermined type, wherein the low-corner frequency of the first shelving filter is U and the high-corner frequency of the first shelving filter is f?, determining, for a second shelving filter of a second predetermined type and of a predetermined order m, a frequency fz for the low-corner frequency of the second shelving filter and a frequency Z4 for the high-corner frequency of the second shelving filter, where h is at least fi, f4 is greater than f3, and f4 is at most fi, and forming the desired shelving filter as a filter combination of the f

Abstract: A method of processing an input audio signal, the method comprising forming a plurality of output audio signals from the input audio signal, wherein each output audio signal is formed by performing respective processing on the input audio signal, wherein for a first output audio signal there is a target audio equalization operation comprising a target filter twice, wherein for the first output audio signal, the respective processing comprises a first audio equalization operation, the first audio equalization operation being the target audio equalization operation modified to compensate for phase shifts that correspond to zeros of the transfer function of the target audio equalization operation, wherein for each output audio signal other than the first output audio signal, the respective processing comprises a compensation filter that compensates for phase shifts that correspond to poles of the transfer function of the target audio equalization operation.

Abstract: A computer-implemented method of determining a configuration for an audio processing operation, wherein the audio processing operation comprises a predetermined set of one or more audio processing sub-operations, each audio processing sub-operation being configurable with one or more respective configuration parameters, the method comprising: specifying the predetermined set of one or more audio processing sub-operations; specifying a target frequency response; and performing a convergent optimization process to determine a configuration for the audio processing operation that reduces a difference between the frequency response of the audio processing operation and the target frequency response, wherein the configuration comprises a respective value for each configuration parameter of each audio processing sub-operation.

Abstract: A method of processing an input audio signal, the method comprising forming a plurality of output audio signals from the input audio signal, wherein each output audio signal is formed by performing respective processing on the input audio signal, wherein for a first output audio signal there is a target audio equalization operation comprising a target filter twice, wherein for the first output 10 audio signal, the respective processing comprises a first audio equalization operation, the first audio equalization operation being the target audio equalization operation modified to compensate for phase shifts that correspond to zeros of the transfer function of the target audio equalization operation, wherein for each output audio signal other than the first output audio signal, the respective 15 processing comprises a compensation filter that compensates for phase shifts that correspond to poles of the transfer function of the target audio equalization operation.

Abstract: A computer-implemented method of determining a configuration for an audio processing operation, wherein the audio processing operation comprises a predetermined set of one or more audio processing sub-operations, each audio processing sub-operation being configurable with one or more respective configuration parameters, the method comprising: specifying the predetermined set of one or more audio processing sub-operations; specifying a target frequency response; and performing a convergent optimization process to determine a configuration for the audio processing operation that reduces a difference between the frequency response of the audio processing operation and the target frequency response, wherein the configuration comprises a respective value for each configuration parameter of each audio processing sub-operation.

Abstract: A method of generating a desired shelving filter for audio data, the desired shelving filter having a low-corner frequency U and a high-corner frequency f2, wherein the difference between the gain of the frequency response of the desired shelving filter at f2 and the gain of the frequency response of the desired shelving filter at U is substantially equal to a non-zero desired amount, the method comprising: determining an order for a first shelving filter of a first predetermined type, wherein the low-corner frequency of the first shelving filter is U and the high-corner frequency of the first shelving filter is f?, determining, for a second shelving filter of a second predetermined type and of a predetermined order m, a frequency fz for the low-corner frequency of the second shelving filter and a frequency Z4 for the high-corner frequency of the second shelving filter, where h is at least fi, f4 is greater than f3, and f4 is at most fi, and forming the desired shelving filter as a filter combination of the f