Improved adaptive feedback cancellation may be used to improve performance of audio amplification systems, such as hearing assistance devices, sound reinforcement systems, telephony, and other acoustic amplification and reproduction systems. This adaptive feedback cancellation allows a significant increase in the maximum stable gain of the amplification system, such as by increasing gain while reducing or eliminating feedback. This improves the audibility provided by an audio amplification system. This may provide particular improvements for hearing assistance devices that include open fittings or otherwise have substantial acoustic leakage. This adaptive feedback cancellation provides additional protection from a dynamically changing acoustic leakage by continually updating itself to model the changes, thereby providing increased gain while reducing or eliminating feedback.