The present application discloses a vibration-based hearing prosthesis configured to measure the vibration applied by a hearing prosthesis to the skull of the hearing prosthesis recipient while the recipient is wearing the hearing prosthesis. Directly measuring the applied vibration in situ allows hearing characteristics to be more accurately mapped to voltage inputs. A recipients hearing threshold and associated voltage input may be directly measured. Additionally, measuring the applied vibrations allows co-listening. A doctor can monitor the sound output from a vibration-based hearing prosthesis as it is worn by a recipient. Directly measuring the vibration output also allows an additional degree of freedom in diagnostics because a recipient can perform diagnostic tests at home.