Manufacture Royale Opera Time-Piece Watch

Now comes the interesting part. See how the case opens up like the bellows of an accordion? This unique design feature is made to create a resonance cage/chamber to allow for the minute repeater to sound more lively. The unfortunate reality is that the complexity of many minute repeaters is diminished by the tinny sound they make after being cased in a watch. The modern needs of a watch with water resistance (as well as the desire for precious metals that absorb sound) has made it a challenge for watch designers to come up with cases that adequately allow for minute repeater complications to sound decent. For Manufacture Royale had to convince engineers to develop this ultra complex style of articulating case — via A Blog to Read