Cartier Ballon Bleu Silver Dial 18kt White Gold Diamond Ladies Watch WE902035

The world of Haute Horlogerie is characterised by the constant, unrelenting pursuit of several goals related to a desire to achieve immutability: perfect, lifelong precision, in all circumstances; materials that remain stable and resistant over time; perpetual calendars; and of course striking mechanisms that are always in tune!

Unfortunately, such a quest is of course in vain, since simply accidentally dropping a timepiece is enough to destroy three centuries of horological research: nothing is immutable here on earth. Nonetheless, striking watches in all their complex refinement are paradoxically the models that prove most resistant to the hazards of daily life.

"Fundamentally, unless you detach gongs from the point to which they are affixed, a striking watch cannot go out of tune", explains Christophe Claret. "Perhaps if the timepiece were to take a particularly hard knock at a very specific angle, the screws might come loose, but as far as I know, it's never happened… And even if that were to occur, one could simply tighten them again". An enlightened enthusiast is naturally tempted to suggest to the master-watchmaker that, in the case of some complex chimes such as the Westminster type, there is a secondary risk: namely, that an impact might distort the gongs and cause them to physically clash, a situation that would definitely produce some discordant sounds. Christophe Claret nips any such idea in the bud: "Not in our models, because we have a patented system designed to prevent that". When pressed for details, that is as much as he is prepared to reveal.

False notes and true complications

Without going as far as imagining detached gongs, can a striking watch end up chiming off-tune? The alloys used for gongs (steel as well as other more secret materials) mean that they are theoretically not particularly subject to variations in temperature. But it's a different story when it comes to music boxes. According to Kurt Kupper, CEO of Reuge, "The only obligation is to activate it at least several times a month. If not, the consistency of the lubricants may change, which would be detrimental to the sound. The other factor is the wooden box that serves as a resonance chamber. The wood may become slightly warped.  Nonetheless, one cannot really say that the box starts to play out of tune; it's more a question of the music having a subtly different tone".

Watchmaking's mission is to foresee the unexpected! Thus, in potential extreme cases where a striking mechanism might no longer be in tune, could it be retuned, like a violin or a piano? The question clearly puzzles Christophe Claret, simply because it has never happened. "In theory, retuning a gong would be much more complicated than replacing it - or even replacing all the gongs, so as to start the musical score over from scratch. The notes played in a tune not only ring true and clear in absolute terms, but are also tuned to each other. If you wish to preserve the overall harmony, changing a single gong would be a tricky proposition. Moreover, one should not rely on the sound frequencies measured by electronic devices; we work with a professional violinist who helps us in creating our harmonic compositions."

Carole Forestier-Kasapi, who is responsible for the development of the Manufacture Cartier movements, concurs with this viewpoint: "A sound has a number of frequencies and sub-frequencies, somewhat like a colour palette. Our goal is to reproduce them as correctly as possible according to a perfect theoretical note, but that's impossible. At the end of the day, the only thing that counts is the harmony perceived by the human ear." Why is it impossible? "Because we are working on the scale of the atom," says Christophe Claret. "During the metal-rolling process, that would mean all atoms moving in the same direction." The quest for harmony on an atomic scale does indeed seem considerably more complicated…

Keeping track of each distinctive sound

To ensure that the harmony of their minute repeater models is duly preserved, several watch manufacturers actually record their 'soundtrack'. Such is the case at Vacheron Constantin as well as Breguet. The latter meticulously preserves these recorded traces of its striking watches, a practice that notably helps to define each model in terms of the sound level and the quality of the sound produced. In particular, tuning is evaluated by comparison with these recordings. Breguet thereby ensures the almost perfect homogeneity of the auditory and musical performances of all models that are bought and sold.