The perception of one’s own voice influences the acceptance of hearing devices, such as headphones, headsets or hearing aids. When these devices fully or partially occlude the ear canal, the wearer’s own voice sounds boomy or like talking in a barrel. This is called occlusion effect. Occluding the ear canal results in an amplification of body-conducted sounds, mainly at low frequencies, and an attenuation of air-conducted sounds, predominantly at high frequencies, compared to the open ear. This contribution provides a comprehensive treatment of Occlusion Effect Cancellation (OEC) and its relation to Active Noise Cancellation (ANC) using digital signal processing. A novel effective filter structure is presented which offers some degree of adaptability and adjustability. Furthermore, digitally opening and closing the ear is evaluated by listening tests and objective measurements.