A hearing aid includes: a BTE hearing aid housing configured to be worn behind a pinna of a user and accommodating at least one BTE sound input transducer configured for conversion of acoustic sound into a BTE audio sound signal; an ITE microphone housing configured to be positioned in an outer ear of the user and accommodating at least one ITE microphone configured for conversion of acoustic sound into an ITE audio sound signal and accommodated by the ITE microphone housing; a signal detector configured for determination of ITE signal magnitudes of the ITE audio sound signal at a plurality of frequencies, and determination of BTE signal magnitudes of the BTE audio sound signal at the plurality of frequencies; and a gain processor configured for determining gain values at respective frequencies of the plurality of frequencies based on the ITE signal magnitudes and the BTE signal magnitudes.