A fitting device for fitting a hearing device to compensate for a hearing loss of a user is disclosed, the hearing device comprising a receiver and a microphone, wherein a feedback path exists between the receiver and the microphone, wherein the hearing device further comprises an adaptive feedback canceller configured to reduce feedback, the adaptive feedback canceller comprising a fixed filter corresponding to an invariant portion of the feedback path, and an adaptive filter corresponding to a variant portion of the feedback path, the fitting device comprising a processor configured to determine the invariant portion of the feedback path, wherein the processor is configured to provide the fixed filter with information relating to the invariant portion of the feedback path independently of the user using the hearing device.