Balanced Armature drivers are enclosed units, available with and without back venting. Which one to choose depends on the desired sound signature and the available air volume within the wearable device enclosure. The Balanced Armature drivers without back vent are ideal for both voice and music, with a balanced sound signature. For these models no additional volume outside the driver enclosure is required. When the designer wishes the wearable device to have elevated bass, a Balanced Armature driver with back vent is recommended. In that case some additional back volume outside the driver enclosure must be provided, just as with a dynamic speaker. However the required air volume will be much smaller when using Balanced Armature drivers.