The present invention intends to render quantization noise virtually imperceptible for a user and to prevent reduction in frequency resolution and reduction in encoding efficiency. Generally, a sequence of protocol messages is provided and a test is performed to test how a device reacts to a specific playback rate for the sequence of protocol messages, wherein the specific playback rate causes a protocol state transition in the device which differs from an expected protocol state transition absent a specific playback delay. The gain factor of the power amplifier associated with the apparatus is then raised during subsequent time slots, such that the measured power drop is compensated for precisely. The corona electrode has a negative polarity.