A method for determining a form for a headphone part using a representative model includes receiving data for at least one ear model. The ear model may be oriented within a coordinate system based on the data, where orienting is focused on the alignment with respect to one or more areas of the ear. A representative model is determined from a plurality of oriented ear models, where the representative model is a representation for a volume determined to be common to at least two oriented ear models. The size and/or shape for the headphone part is determined based upon the representative model.