Bulgari - Octo Grande Sonnerie

The latest creation from Bulgari in the Octo collection is a haute horlogerie timepiece which features Grande and Petite Sonnerie, Minute Repeater, Westminster Chime functions, as well as a Tourbillon system.

Bulgari's creations interpret the entire range of this product type, including models with two, three and four hammers and gongs. The latter category is, of course, 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.

For the Octo Grande Sonnerie, Bulgari chose to develop a contemporary product housing the complex Grande Sonnerie mechanism within the innovative case that was used also for the acclaimed Octo Minute Repeater launched in 2016, here redesigned to satisfy various technical requirements.

The 44 mm titanium case is characterized by a black DLC (Diamond Like Carbon) surface treatment for the case middle while the bezel and the caseback are both sandblasted.

The choice of titanium was driven by technical reasons. Thanks to its resistance, its lightness and its low density, this metal offers the best possible chiming characteristics.

To guarantee a perfectly audible and clear sound, the case was designed as 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 enhanced, while reducing the weight of the watch.

The decision to secure the movement to the case by internal “ears” (wings) was a deliberate choice for functional reasons: this construction 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 30 metres / 100 feet. Rotating selectors serve to choose between Strike/Silence and Grande Sonnerie/Petite Sonnerie modes.

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 3 Hz (21,600 vph) movement. The power reserve of the movement is 48 hours while the striking mechanism has an autonomy of 24 hours in Grande Sonnerie mode or 28 hours in Petite Sonnerie mode.

The back of the case is fitted with a sapphire crystal pane to reveal the tourbillon mechanism.

Completed by a rubber-coated alligator leather strap with a titanium folding clasp, the Bulgari Octo Grande Sonnerie is a one-off edition. Price on request. bulgari.com