More than a decade in the making, the Grand Sonnerie is Greubel Forsey’s most complicated creation to date
By Chris Hall
So used have we become to seeing Greubel Forsey refine the tourbillon, over and again, that it comes as something of a surprise to find the brand has broadened its horizons to encompass one of watchmaking’s other highly-prized achievements.
Chiming watches have enjoyed a resurgence in recent years, boosted by the type of ingenious R&D that has seen Audemars Piguet invent the SuperSonnerie, Bulgari bring out an ultra-thin repeater, and Chopard’s LUC Full Strike incorporate sapphire crystal into the strike works.
Greubel Forsey’s first foray in this domain isn’t just a minute repeater but a Grand Sonnerie to boot. You have the option – controlled by the pusher at four o’clock – of hearing a grand sonnerie (chiming all hours and quarters), petite sonnerie (just the hours), or no sonnerie at all, plus you can at any time activate the minute repeater to hear the time chimed out in hours, quarters and minutes.
The watch – which, being a Greubel Forsey does of course also include a 24 second tourbillon – contains a stupendous 935 parts. The tourbillon, which bulges out of the case at eight o’clock, is still the most prominent part of the design, although it shares dial space with a large sonnerie power reserve, opposite at two o’clock.
Chiming mechanisms are power-hungry things; most minute repeaters need winding after a handful of uses. A grand sonnerie needs to be able to keep going for longer if it’s to fulfil its function; even more so if you’re going to expect to be able to use the minute repeater intermittently as well. The solution found by Greubel Forsey is to introduce an automatic rotor to power the sonnerie works, while leaving the timekeeping functions of the watch manually-wound.
That gives about 20 hours of grand sonnerie action in typical use, and in theory allows for constant use, assuming the watch is worn regularly enough (or stored on a winder). The main movement, beating at 21,600vph, has a three-day power reserve.
Some of those 935 components have, naturally, gone into developments to improve the watch’s sound; with the aforementioned repeaters already out there, you can’t release a chiming watch in 2017 without some sort of technical magic to improve upon the chime.
Here, we have a titanium “resonance cage” designed to amplify the sound of the gongs, plus a total of eleven “security measures” to prevent user error disrupting the highly complex movement; you can’t use the sonnerie selection switch while it’s chiming, for instance.
The watch shares a lot with the Vacheron Constantin Atelier de Cabinotiers Symphonia; Vacheron Constantin partnered with Complitime, Greubel Forsey’s custom movement workshop to create the striking works. A lot of the basic statistics are the same – sonnerie power reserve, for example – and others differ slightly. For instance, Vacheron Constantin claims just six safety measures to Greubel Forsey’s 11. We will have a more in-depth comparison of these two watches in the coming weeks.
The watch is water-resistant to 30m – rain-proof, in other words – and will cost CHF 1,150,000 + VAT.