Apparatus and method for estimation of eardrum sound pressure based on secondary path measurement

A hearing device operable to be fitted into an ear canal of an individual, comprising:

• a memory configured to store a least squares estimate and a reduced dimensionality estimate that that both estimate a relative transfer function between secondary path measurements and associated acoustic transducer-to-eardrum response of the hearing device;
• an inward-facing microphone configured to receive internal sound inside of the ear canal;
• an acoustic transducer configured to produce amplified sound inside of the ear canal;
• a processor coupled to the memory, the inward-facing microphone, and the acoustic transducer, the processor operable via instructions to:
• determining a cutoff frequency for the individual based on a secondary path measurement performed on the individual;
• determining a first acoustic transducer-to-eardrum response below the cutoff frequency using the secondary path measurement and the least squares estimate;
• determining a second acoustic transducer-to-eardrum response above the cutoff frequency using the secondary path measurement and the reduced dimensionality estimate;
• and
• predicting a sound pressure level caused by the hearing device at an eardrum of the individual using the first and second acoustic transducer-to-eardrum responses.