Hearing aid configured to perform a recd measurement

A hearing aid adapted to be worn at and/or in an ear of a user, the hearing aid comprising

• an earpiece adapted for being located fully or partially in an ear canal of the user, the earpiece being configured to define a residual volume in the ear canal between the earpiece and an eardrum of the user when the earpiece is mounted in the ear canal of the user, where the earpiece comprises
• at least one ventilation channel or opening configured to allow an exchange of air between the residual volume and an environment of the hearing aid, and
• a sound outlet allowing sound from an output transducer of the hearing aid to be played into the residual volume;
• a signal processor configured to, at least in a specific RECD estimation mode of operation of the hearing aid, estimate frequency dependent real ear to coupler values for said hearing aid when mounted in the ear canal of the user by
• based on a feedback signal picked up by an input transducer of the hearing aid, providing a frequency dependent feedback path estimate representative of a leakage of sound from the output transducer to the input transducer;
• estimating a low-frequency RECD value;
• estimating a quarter wavelength notch at a relatively high frequency from said feedback path estimate;
• estimating a high-frequency RECD value in dependence of said estimated quarter wavelength notch;
• and
• determining estimated frequency dependent RECD values in dependence of the estimated low-frequency RECD value and the estimated high-frequency RECD value.

A hearing aid adapted to be worn at an ear of a user, the hearing aid comprising

• an ITE-part adapted for being located fully or partially in an ear canal of the user and configured to define a residual volume in the ear canal between the ITE-part and an eardrum of the user when the ITE-part is mounted in the ear canal of the user;
• and comprising
• at least one ventilation channel or opening configured to allow an exchange of air between the residual volume and an environment of the hearing aid and to allow an exchange of air between said residual volume and an environment of the hearing aid, when the ITE-part is mounted in the ear canal of the user, and
• a sound outlet allowing sound to provide that said output sound is delivered to the residual volume when the ITE-part is mounted in the ear canal of the user,
• wherein the hearing aid is configured to
• provide a frequency dependent feedback path estimate;
• estimate a low-frequency-roll-off-resonance frequency from the feedback path estimate;
• estimate a low-frequency RECD value in dependence of the estimated low-frequency-roll-off-resonance frequency;
• estimate a high-frequency RECD value;
• and
• determine estimated frequency dependent RECD values in dependence of the estimated low-frequency RECD value and the estimated high-frequency RECD value.