One of the ultimate strongholds of the grand horological tradition, chiming watches remain the preserve of a select circle of Maisons to which Bulgari belongs. The brand masters each of the subtle details and finer points of this domain - two-hammer minute repeater, three-hammer carillon and four-hammer grande sonnerie - and is undoubtedly currently dominating the chiming watch market. In parallel with the world record launched in 2016, Octo Minute Repeater, its creations interpret the entire range of this product type, including models with two, three and four hammers and gongs. The latter category is the most emblematic and also the rarest: only a handful of Maisons are capable of mastering it, with varying degrees of success and within a generally very classical overall approach.
In keeping with the spirit that inspires it, epitomising a blend of Italian values and Swiss expertise while consistently exploring uncharted territory, Bulgari has chosen to develop a contemporary product with an innovation-driven attitude. The complex Grande Sonnerie mechanism, which includes a tourbillon, is housed within the new Octo case, redesigned in accordance with modern and resolutely urban proportions. The choice of titanium was guided by technical imperatives. Its resistance, its lightness and its low density combine to offer the best possible chiming characteristics.
The challenge of any chiming watch is to guarantee a perfectly audible and clear sound. This objective depends not only on the movement itself, but also on its integration within the case. In the case of the Octo Grande Sonnerie, the development and the construction of the case have been designed to create a ‘sound box’ serving to optimise the sound as well as its diffusion. The case middle features striped lateral grooves which combine with a circular inner tunnel housed in the case middle and surrounding the movement. Both the amplification and the propagation of the sound are thus notably enhanced, while reducing the weight of the watch.
The decision to secure the movement to the case by internal “ears” (wings) contributes to optimising the transmission of the vibrations generated by the striking mechanism. Among the other innovations applied to this creation, the striking mechanism is activated not by a sliding bolt, but instead via a pusher which thereby ensures water resistance to 30m; while innovative rotating selectors serve to choose between Strike/Silence and Grande Sonnerie/Petite Sonnerie modes.
From an aesthetic standpoint, this 44mm-diameter case which is both complex and difficult to manufacture is endowed with a technical yet elegant structure. The titanium is given several different treatments: a DLC (Diamond Like Carbon) black surface for the case middle integrated between the bezel and caseback, which are both sandblasted. Beneath the sapphire crystal, a single element – in the shape of a minute circle bearing anthracite black hour-markers and two power-reserve segments respectively dedicated to the movement and the striking mechanism – ensure an unobstructed view of the movement. The back of the case fitted with a sapphire crystal pane reveals the tourbillon mechanism.
Octo Grande Sonnerie is a one-off edition. Its complexity can be summed up in a few figures: the Grande Sonnerie mode is activated 35,040 times a year, whereas the hammers will strike the gongs no less than 433,580 times during the same period! In Petite Sonnerie mode, the hammers will annually hit the gongs 262,760 times!
