A method of manufacturing a hearing aid preferably includes the steps of: placing a moldable material in the ear canal of a patient to cast a form; using the form to form a hollow shell with an outer surface that approximates the shape of the patient's ear canal, the shell being of a soft polymeric material providing a mounting member; mounting electronic hearing aid components to the mounting member; joining the mounting member to the hollow shell to define a mold cavity; and filling the shell with a soft polymeric material that substantially encapsulates at least one of the electronic components and bonds to the mounting member, wherein the combination of shell, electronic components and soft polymeric material define a soft structure that is compliant to ear canal movement during use.