Embodiments include a head-worn computer comprising, a front frame mechanically adapted to secure a see-through computer display; an arm, secured to the front frame, mechanically adapted to secure the front frame to the head of a user; and the arm comprising an internal speaker system, enclosed by the arm, wherein the internal speaker system comprises a back cavity and a speaker, the arm further comprising an inlet vent positioned to vent the back cavity and an audio outlet vent positioned to vent the speaker.