Audio processing device

An audio processing device, comprising:

• a first active noise cancellation (ANC) filter, configured to generate a first anti-noise signal by applying only a time domain filtering to a full band of an error signal during an ANC period, the error signal is representative of audible sound at a target space;
• and
• a second ANC filter, configured to generate a second anti-noise signal by applying only the time domain filtering to the full band of the error signal during the ANC period,
• wherein the first and second anti-noise signals are each simultaneously converted into an acoustic anti-noise signal to cancel environmental noise, or the first and second anti-noise signals in combination are converted into the acoustic anti-noise signal to cancel environmental noise,
• wherein the acoustic anti-noise signal is included in the error signal, and wherein the first ANC filter is connected to the second ANC filter in parallel,
• wherein the first ANC filter and the second ANC filter are independent of each other, and
• wherein the ANC period excludes a transition period in which both the first ANC filter and the second ANC filter temporarily generate the first anti-noise signal and the second anti-noise signal prior to only one of the first ANC filter and the second ANC filter generating the corresponding one of the first anti-noise signal and the second anti-noise signal.