1. A method, comprising: determining a target phase response for an all-pass recursive filter, the all-pass recursive filter being representable with a transfer function having N zeros and N poles, the N zeros having a one to one correspondence relationship with the N poles; specifying an initial value of N; (a) identifying, based at least in part on the target phase response, a set of optimized values for a set of filter coefficients for the all-pass recursive filter; and (b) determining whether the all-pass recursive filter with the set of optimized values for the set of filter coefficients satisfies one or more criteria; wherein the above steps of determining, specifying, (a) identifying, and (b) determining are performed with one or more computing devices; in response to determining that the all-pass recursive filter with the set of optimized values for the set of filter coefficients does not satisfy the one or more criteria, incrementing N and repeating steps (a) and (b); in response to determining that the all-pass recursive filter with the set of optimized values for the set of filter coefficients satisfies the one or more criteria, causing the all-pass recursive filter to be implemented in one or more semiconductor integrated circuits in a media processor, the media processor using the all-pass recursive filter to process first media samples in a first signal path of two or more signal paths, while the media processor is processing second media samples without the all-pass recursive filter in a second different signal path of the two or more signal paths.