According to an aspect, a hearing device such as a bone conduction hearing aid is disclosed. The device includes an implantable prosthetic system comprising a receiver coil, and an external audio processor device. The audio processor device includes a microphone configured to transform a received sound into an electrical input signal, a signal processor configured to process the electrical input signal into a processed electrical data signal, a transmitter coil configured to inductively transmit data signals and/or power, across the skin of a hearing device user, to the receiver coil. The audio processor device further includes a detection device configured to detect if the external audio processor device is within a predefined distance from the implantable prosthetic system or to detect if a coupling coefficient between the transmitter coil and a receiver coil is within a predefined value range.
