For SIHH 2017, Greubel Forsey has announced a timepiece that required 11 years research and development and assembly of no fewer than 935 parts. We’re talking about their very first chiming complication, simply called Greubel Forsey Grande Sonnerie. The most important elements and indications (such as the tourbillon, the cathedral gongs, the striking hammers, and the power reserve and mode indicators) were incorporated with the greatest care to ensure architectural balance.
This was no mean feat – the watch designers succeeded in housing the 935 parts comprising this timepiece and its exterior in a space measuring 43.5 mm in diameter and 16.13 mm high. The Grande Sonnerie is well and truly Greubel Forsey’s most complex creation to date.
The movement is manually wound, but the striking mechanism features a self-winding system which provides about 20 hours of power reserve in Grande Sonnerie mode. The minute repeater and its additional striking mechanism sounds the exact time on demand, down to the minute. The specific characteristics of this timepiece include, in particular: 21,600 vibrations/hour and a 72-hour chronometric power reserve.
This timepiece has three modes to choose from: Grande Sonnerie (which strikes the hours and the quarters in passing), Petite Sonnerie (which strikes the full hours in passing) and Silence (which does not strike in passing). The pure and rich sound of the Grande Sonnerie is enhanced by an acoustic resonance cage made from titanium.
Having all this in mind, it is no surprise that five to eight pieces of this timepiece will be realised a year.