An active noise cancellation (ANC) system may include provisions for validating the accuracy of a modeled transfer characteristic stored in secondary path filters, which provides an estimate of the secondary path (i.e., the transfer function between a speaker and an error microphone). Using estimated anti-noise or music signals to adjust an error signal from the error microphone, a signal analysis controller may detect ANC instability or noise boosting. Such noise boosting may indicate the stored transfer characteristic in the secondary path filter does not accurately represent the actual secondary path. According, upon detection of noise boosting, the stored transfer characteristic of the secondary path filters may be modified.