A noise-cancellation system, comprising: a noise-cancellation filter configured to generate a noise-cancellation signal; an actuator configured to receive the noise-cancellation signal and to transduce a noise-cancellation audio signal based on the noise-cancellation signal, the noise-cancellation audio signal destructively interfering with an undesired noise in a noise-cancellation zone in a predefined volume; an error sensor configured to output an error sensor signal, the error sensor signal being representative of residual undesired noise in the noise-cancellation zone; a performance cost filter configured to receive and filter the error sensor signal and to output a performance cost filter signal, the performance cost filter signal being representative of the error sensor signal as weighted by a performance cost function; an adaptive processing module configured to receive the performance cost filter signal and to adjust the noise-cancellation filter such that the noise-cancellation audio signal minimizes the performance cost filter signal; an actuator effort cost filter configured to receive and to filter the noise-cancellation signal and to output an actuator effort cost filter signal, the actuator effort cost filter signal being representative of the noise-cancellation signal as weighted by an actuator effort cost function, wherein the adaptive processing module is further configured to receive the actuator effort cost filter signal and to adjust the noise-cancellation filter such that the noise-cancellation audio signal minimizes the actuator effort cost filter signal; characterized in that the performance cost filter is configured to convolve the performance cost function with the conjugate transpose of the performance cost function to weight the error sensor signal with both the performance cost function and the conjugate transpose of the performance cost function wherein the actuator effort cost filter is configured to convolve the actuator effort cost function with the conjugate transpose of the actuator effort cost function to weight the noise-cancellation signal with both the actuator effort cost function and the conjugate transpose of the actuator effort cost function. a noise-cancellation filter configured to generate a noise-cancellation signal; an actuator configured to receive the noise-cancellation signal and to transduce a noise-cancellation audio signal based on the noise-cancellation signal, the noise-cancellation audio signal destructively interfering with an undesired noise in a noise-cancellation zone in a predefined volume; an error sensor configured to output an error sensor signal, the error sensor signal being representative of residual undesired noise in the noise-cancellation zone; a performance cost filter configured to receive and filter the error sensor signal and to output a performance cost filter signal, the performance cost filter signal being representative of the error sensor signal as weighted by a performance cost function; an adaptive processing module configured to receive the performance cost filter signal and to adjust the noise-cancellation filter such that the noise-cancellation audio signal minimizes the performance cost filter signal; an actuator effort cost filter configured to receive and to filter the noise-cancellation signal and to output an actuator effort cost filter signal, the actuator effort cost filter signal being representative of the noise-cancellation signal as weighted by an actuator effort cost function, wherein the adaptive processing module is further configured to receive the actuator effort cost filter signal and to adjust the noise-cancellation filter such that the noise-cancellation audio signal minimizes the actuator effort cost filter signal; characterized in that the performance cost filter is configured to convolve the performance cost function with the conjugate transpose of the performance cost function to weight the error sensor signal with both the performance cost function and the conjugate transpose of the performance cost function wherein the actuator effort cost filter is configured to convolve the actuator effort cost function with the conjugate transpose of the actuator effort cost function to weight the noise-cancellation signal with both the actuator effort cost function and the conjugate transpose of the actuator effort cost function.