A method for manufacturing a cartilage conduction audio device is disclosed. A manufacturing system receives data describing a three-dimensional shape of an ear (e.g., the outer ear, behind the ear, the concha bowel, etc.) of a user. The system identifies one or more locations for one or more transducers along a back of an auricle of the ear for the user that vibrate the auricle over a frequency range causing the auricle to create an acoustic pressure wave at an entrance of the ear canal. The system then generates a design for a cartilage conduction audio device for the user based on the one or more identified locations of the transducers at which acoustic pressure waves generated by the one or more transducers satisfy a threshold performance metric for the user. The design may then be used to fabricate the cartilage conduction audio device.