Abstract: A head-mounted wearable device (HMWD) provides audio output using acoustic quadrupole units (AQU). The AQU produces an acoustic pattern having a first region and a second region. The first region has a first phase and the second region has a second phase that is opposite the first phase. A major axis extending through the regions is directed generally upwards from the ear canal of the user. The ear of the user is within the first region. The second region is directed upward. Bystanders are within an acoustically null region of the acoustic pattern. The acoustically null region is perpendicular to the major axis. Within the acoustically null region, the sound intensity is reduced due to destructive interference between the first phase and the second phase. As a result, the user wearing the HMWD is able hear audio output while audio amplitude perceived by the bystanders is significantly reduced.

Abstract: A head-mounted wearable device (HMWD) may be fashioned that includes temples that pass near each ear of the user. To accommodate different head shapes and sizes, a head contact piece may be mounted to the temple. Head contact pieces with different profiles may be used to improve user comfort, aid in retaining the HMWD on the user's head, improve performance of output devices such as bone conduction speakers, and so forth.