The Overseer Music Box is a device used by Warfare Overseers, which, when activated, prevents the use of any supernatural abilities within range, and can send out a sound-wave barrier to keep Corvo Attano away.
As such, Corvo is required to use his ranged and melee weaponry to combat Overseers who use them. The music box can also harm Corvo by firing Windblast-like waves that push him backward, deal heavy damage and negate magical powers.
Corvo first discovers the device in the workshop located in the Backyard of the Office of the High Overseer, where it is described in a note and called "Holger's Device". According to the studies of the Abbey of the Everyman, the box produces "mathematically pure" notes, which act on the theory that there are hidden waves throughout the natural world.
In an audiograph recorded by the Abbey's High Artificer, the concern is raised over whether or not the mechanism and its effects are themselves magic. However, this issue is not addressed by any other members of the Abbey.
Overseers carrying this music box can be especially deadly. In addition to having their faces shielded by masks, those who carry the box can use it to protect themselves from strikes to the chest. The box's great range, ability to block damage, and Corvo's hampered ability to flee without his powers make music box Overseers priority targets during combat.
A good strategy to kill an Overseer with a music box is to fire an incendiary bolt at his legs, as Overseers move slowly when carrying a music box and are easy targets. Grenades or explosive bullets will also do the job. If taking the low chaos approach, always make sure to get rid of Overseers with music boxes first. Their music can stop Corvo mid-Blink and can cancel Possession.
- Even though it is implied that Bone Charms, which usually emit some warmth, turn cold and useless close when in the vicinity of the music, Corvo's charms will continue to work normally.
- Two City Watch Officers can be overheard in the Estate District discussing a rumor that a group of Overseers declared a woman a witch because she lost her voice just as Overseers passed by with a music box.
- Music boxes can also break glass and cause whale oil tanks to explode.
Enemies in Dishonored