1. A method for controlling adaptivity of signal modification, comprising: receiving a signal; updating a primary adaptation coefficient based on whether the primary adaptation coefficient satisfies an adaptation constraint; if the primary adaptation coefficient fails to satisfy the adaptation constraint: updating the primary adaptation coefficient based on whether a secondary adaptation coefficient satisfies the adaptation constraint of the signal, the primary and secondary adaptation coefficients both being based on the signal and updated with the same time constant; the secondary adaptation coefficient being a phantom coefficient such that the phantom secondary adaptation coefficient is not applied to the signal; the primary adaptation coefficient being updated toward a current observation if the phantom secondary adaptation coefficient satisfies the adaptation constraint of the signal; and the primary adaptation coefficient not being updated if the phantom secondary adaptation coefficient does not satisfy the adaptation constraint; generating a modified signal by applying the primary adaptation coefficient to the signal; and outputting the modified signal.