A method and apparatus for adapting dual filters is disclosed. In one
aspect, a method may include transforming a signal, adapting a first
adaptive filter based on the transformed signal, estimating a delay of an
impulse response based on the adaptation of the first filter, delaying a
signal based on the estimated delay, and adapting a second adaptive
filter based on the delayed signal. In one aspect, an echo or other
unwanted signal may be reduced or cancelled based on the adaptation of
the second filter.