FIGS. 3A and 3B are side and rear perspective views, respectively, of the open-ear headphone 10 in place on outer ear 50. The manner in which open-ear headphone 10 interacts with outer ear 50 may be better understood with reference to parts of outer ear 50 illustrated in FIG. 3A. Outer ear 50 includes helix 56, anti-helix 57, lobule 64, tragus 62, and concha 60 that includes cavum conchae 51 with anti-tragus 58 forming the lower border of cavum conchae 51. Depending on the user's outer ear anatomy and the user's preference for the fit of the open-ear headphone, body portion 16 can be configured to pass over one or more of helix 56, anti-helix 57, lobule 64, and anti-tragus 58. Body portion 17 passes over the outer edge 59 of the ear at the location of one or more of helix 56, anti-helix 57, and lobule 64.

In some examples open-ear headphone 10 carries one or more external microphones. External microphones can be used to sense the user's voice and/or sense environmental sounds and/or as feed-forward microphones of an active noise cancelation system; these and other functions of external microphones of a headphone are known in the technical field and so are not further described herein. In this example, external microphones 71 and 72 are located in opposed sides of body portion 16 such that they lie generally along axis 73 that intersects or passes close to the expected location of the user's mouth. This way the microphones can be beam-formed if desired. Beamforming is also known in the technical field and so is not further described herein.