The Arena Metasonic is an exclusive work of Gérald Genta. It is an ultimate evolution of the Arena Grande Sonnerie watch created by the Maestro. It was launched as a wristwatch in 1994 and regularly improved since. The in-house developed Grand Sonnerie complication now sports a revolutionary case. Merging new materials and enhanced construction, Arena Metasonic makes enchanting melodies.
Among Sonnerie (striking) watches, a distinction is made between repetitions – at quarters, at 5 minutes and, most often, at minutes – and Grand Sonneries which generate up to 35,040 déclenchements (triggers) per year.
The Grand Sonneries which strike the hours and quarters in passing are systematically coupled with the minute repeater function which rings the hours, quarters and minutes on demand. We then hear successively the hours on a low gong, the quarters on 2, 3 or 4 gongs, and the minutes on a high gong. At Gérald Genta, Grandes Sonnerie is a specialty that has long been mastered.
All the Gérald Genta Grandes Sonnerie wristwatches are exceptionally complex. With their four hammers and their carillon Westminster chimes with different melodies for each quarter, they represent 15 years of unparalleled prowess and they are all the more remarkable as they are developed on tourbillon movements.
The Grand Sonnerie watches currently produced include around 850 pieces in the manual version, 950 in the automatic version, 1,100 in the version with a perpetual calendar, and it takes nearly a year of work to produce just one. 61 pieces came from Gérald Genta workshops from 1994 to today.
Gérald Genta allows all the extravagances in the dressing of watches. In the same way it maintains its great respect to the traditional watchmaking. Evidenced by the craftsmanship of its movements, which are part of authentic haute horlogerie, with decorations and finishes still largely handmade.
Among the complex horological mechanisms, Sonneries stand apart. While any other mechanical caliber can now be industrialized, and therefore reproducible identically whatever the predefined criteria, a sonnerie necessarily requires manual retouching.
The watchmaker acts on the length of the gongs or on their attachment point to obtain the desired notes. In this exercise, it is customary to work with the ear at the risk of never achieving the same result, including when it comes to the same person. Gérald Genta has undertaken to solve the problem and his ringtones have been standardized for 4 years now.
In collaboration with an acoustics laboratory, Gérald Genta has developed exclusive software that allows him to measure the sounds produced, in particular by his Grand Sonneries. Three main criteria were retained. First, the craftsmen measure the intensity or strength of the notes in decibels. To be validated, they must have sufficient intensity to be clearly audible but not too high to preserve the harmonic quality.
Then, they control the tuning or the accuracy of the notes in order to invariably obtain a sol for the hours, do, ré, mi and sol for the different combinations of quarters – precisely: mi-ré-do-sol, ré-sol-mi-do + mi-ré-do sol, mi-do-résol + ré-sol-mi-do + mi-ré-do-sol -, one ré for the minutes, all in octaves 5 or 6 , serious enough to be melodious.
Finally, the rate or regularity in milliseconds is checked at intervals defined between each hour (628 ms), each quarter (427 ms), and each minute (509 ms). The objective is to ensure a harmonious sequence with distinctly perceptible sounds.
Thanks to these measures, which are completely independent of each other, the Grand Gérald Genta ringtones are now of equal quality. The watchmaker’s alterations are always essential but they converge on common criteria, guaranteeing a unique melody. It takes on average a dozen successive checks to obtain the desired result.
Each Grand Sonnerie reacts in its own way, depending on the volume occupied by the movement in the case and the recesses it contains, the materials chosen and their treatment, the strength of the hammers as well as a multitude of details such as the quality of screws, joints and welds. The gongs are now attached to the middle of the case, and no longer to the movement, which has the effect of increasing the sound volume.
The improvements apply both to the automatic grand strike, presented in the Octo collection since 2003, and to the manual grand strike, an Arena dating from 1999 honored with the prestigious Hallmark of Geneva. The latter is characterized by its movement which fully emphasizes the striking mechanism, presented through a large opening on the dial side, to the left of the off-center hour and minute display.
On the back, you can admire the tourbillon and follow the evolution of the power reserves, from 48 hours for the movement, to 24 hours for the striking. A security system locks the crown each time it rings so as to avoid accidentally damaging the striking mechanism.
Having reached the pinnacle of mastery of its grand strike mechanism, Gérald Genta wished to offer it a tailor-made case, specifically developed to enhance its musicality. To do this, it has acquired software, developed in collaboration with a French university, capable of analyzing all kinds of materials. It has produced a system of tests which take account of the density, the modulus of elasticity and the loss coefficient, physical parameters which are decisive in the diffusion of sound, which must be as low as possible.
The first parameter to be taken into account, the density must be less than 5. However, among the metals most used in watchmaking, only titanium meets this requirement. Its density is half that of steel, itself half that of white gold. In terms of modulus of elasticity, estimated to be of superior quality when it is below 100 GPa (GigaPascal), white gold and titanium approach the threshold when the steel moves away from it twice.
As for the loss coefficient, measured with precision in the laboratory – from calibrated bars vibrated by laser under vacuum, without contact and freely damped -, it is lower than the desirable maximum of 0.0002 for gray gold and gray titanium but not steel. It is clear that titanium and gold are surprisingly more efficient than steel which is not very dense, but which absorbs sound more than any other material (high loss coefficient).
Gérald Genta has resolved to aim for excellence by creating an alloy according to the objectives of each parameter, the composition of which will remain secret. Patented and called Magsonic®, it won the palm with 2.7 in density, 71 GPa in elasticity and 0.00008 in loss, or respectively 50%, 30% and 60% better compared to the parameters set as objectives.
Thus, it constitutes the stature of the last of the great house ringtones, for its part called Arena Metasonic. Note that the middle is a crucial element in ring tones because the sound tends to diffuse sideways. It is important to choose a suitable material and to refine it as much as possible.
It will be seen that the quality obtained is even better when the watch is worn, with the back resting on the wrist. In addition, Gérald Genta was able to measure the sound intensity (sound pressure index, force and melody) produced by the different materials using specific test boxes. The result is that, here again, the Metasonic outperforms the others, both in strength (overall intensity of the sounds) and in melody (effective intensity of the desired notes: do, ré, mi and sol).
The Metasonic watch benefits from an original case, itself patented for its construction, inspired by the snare drums. The middle is surrounded by a bezel and a back in grade 5 titanium fixed from the outside, via pillars designed for this purpose. Thus, no screw disturbs the diffusion of sound. The result is also a very original creation, in perfect harmony with the spectacular design of the watches signed Gérald Genta.
The construction has been made waterproof because, contrary to popular belief, the sound is not better in a non-waterproof watch. It may even be disturbed when exiting through the bottlenecks formed by the air passages around the winding pushers. Some old pocket watches solved the problem by distributing openings all around, a solution of course unsuitable for wristwatches.
The innovations presented here by Gérald Genta are a contemporary response to raising the level of quality like never before. They are the first to emerge from a particularly ambitious research and development program.
The Arena Metasonic, 46mm in diameter at the middle, 50mm in total, features polished vertical surfaces and satin-finished horizontal surfaces. The watch comes fitted with an ostrich strap. The crown bears the individual watch number and the ringing controls, allowing the switch to grand strike, small strike, minute repeater or silent mode, are easily accessible on the opposite side.
On the move, Gérald Genta inaugurates a decor with a wavy pattern in a nod to the propagation of sound. The jewels are in white sapphire for the sake of harmony with the set which, exceptionally, does not receive the old gold treatment of the Potter finish.
The Arena Metasonic is delivered in a glass safety box, in which it is invisible until the owner activates the biometric button programmed for him.