Acoustic echo cancellation with room change detection

An acoustic echo cancelling controller configured to receive a source signal representative of sound broadcast at a first position in a room and a sink signal representative of sound picked up at a second position in the room, the sound picked up at the second position being transferred from the first position according to a transfer characteristic, the controller comprising:

• a first acoustic echo canceller configured to receive the source signal and the sink signal, and to model the transfer function in an adaptive manner based on a first set of coefficients, the first acoustic echo canceller being further configured to provide a first error signal representative of an echo-free residual signal, the first error signal forming an output signal of the controller;
• a second acoustic echo canceller configured to receive the source signal and the sink signal, and to model the transfer function in a non-adaptive manner based on a second set of coefficients, the second acoustic echo canceller being further configured to provide a second error signal;
• a memory operatively coupled with the first acoustic echo canceller and the second acoustic canceller, the memory being configured to store sets of coefficients from the first acoustic echo canceller as sets of reference coefficient and to provide stored sets of reference coefficients to the second acoustic echo canceller;
• and
• a room change detector operatively coupled with the first acoustic echo canceller and the second acoustic echo canceller, the room change detector being configured to:
• evaluate the first error signal and the second error signal, and detect a room change if the evaluated second error signal is greater than a sum or product of the evaluated first error signal and a first threshold,
• set, for a predetermined period of time, the second set of coefficients equal to the first set of coefficients if a room change is newly detected, and
• copy one of the sets of reference coefficients from the memory to the second acoustic echo canceller and copy the first set of coefficients from the first acoustic echo canceller as another set of reference coefficients into at least one of the second acoustic echo canceller and the memory if a room change is still detected.