Limited Edition of 10 Pieces (MSRP (US$900,000 ea)
An alliance of tradition and engineering for the ultimate Grande Sonnerie, the most complicated of its kind in the world for over 15 years
The latest evolution of the Arena Grande Sonnerie, the Arena Metasonic raises the exclusive work of Gérald Genta to the realm of perfection. Launched as a wristwatch in 1994 and regularly improved ever since, the noble proprietary complication that was already considered beyond compare further enhances its pedigree by appearing in a revolutionary new case. An original material and unprecedented construction combine to ensure an enchanting chime, embodying progress stemming from in-depth acoustic and vibratory research that simultaneously overturns certain preconceived ideas.
Striking watchesStriking watches are classified into quarter, five-minute and most frequently minute repeater models, and Grande Sonnerie or “grand strike” variations can be triggered up to 35,040 times a year. They strike the hours and quarters automatically or “in passing”, as well as being systematically equipped with the minute repeater which strikes the hours, quarters and minutes on request. The watch then successively chimes the hours on a low-pitched gong, the quarters on two, three or four gongs, and the minutes on a high-pitched gong. Grande Sonnerie watches are a long-established speciality at Gérald Genta. It has introduced a number of exceptionally complex wristwatch models since 1994. With their four hammers and their Westminster chime playing a different tune for each quarter, they represent 15 years of peerless accomplishments and are all the more remarkable in that they are developed on tourbillon movements. The Grande Sonnerie models comprise approximately 850 parts for the hand-wound models, 950 for the self-winding versions, and 1,100 for those equipped with a perpetual calendar. It takes around a year’s work to craft just one such watch, and only 61 in all have emerged from the Gérald Genta workshops since 1994. Connoisseurs, and especially master-watchmakers, unanimously confirm that it is not the accumulation of functions that makes a watch complicated, but instead the intrinsic complexity of the movement to be assembled and cased up.
Traditional movementsWhile Gérald Genta is a brand famed for its daring approach to watch exteriors, it is nonetheless extremely respectful of traditional horology, as is confirmed by the superlative workmanship displayed in its authentic Haute Horlogerie movements featuring a wealth of hand-crafted decoration and finishing. Among them are striking watches, which can be viewed as the last bastion of pure watchmaking artistry. Whereas virtually any other movements can now be industrially made and thus identically reproduced according to predefined criteria, a striking mechanism necessarily calls for manual intervention. The watchmaker adjusts the length of the gongs or their point of attachment in order to achieve the desired notes. This delicate exercise is generally performed by ear, with the inherent risk of never achieving the same result twice, even when the same person is involved. Gérald Genta therefore decided to solve this particular problem and its striking watches have now been effectively standardised to measurable norms for the past four years.
Standardised striking watchesBased on research conducted in cooperation with an acoustic laboratory, Gérald Genta has an exclusive software programme enabling it to measure the sounds produced in particular by its Grande Sonnerie watches. Three main criteria have been established. First of all, the intensity or the force of the notes: to earn approval, they must demonstrate a level of intensity sufficient to ensure they are clearly audible, but not excessively high in order to preserve their harmonic quality. The harmony or the correct pitch of the notes is then checked to ensure a sol (G) is consistently sounded for the hours, do, re, mi and sol (C,D,E and G) for the various combinations of quarters – more specifically mi-re-do-sol (E-D-C-G), re-sol-mi-do (D-G-E-C) + mi-re-do-sol (E-D-C-G), mi-do-re-sol (E-C-D-G) + re-sol-mi-do (D-G-E-C) + mi-re-do-sol (E-D-C-G) – and re (D) for the minutes. All are the notes are within the fifth and sixth octaves, ensuring they are low enough to be truly melodious. Finally, the cadence or regularity in milliseconds is verified according to defined intervals between each hour (628 ms), each quarter (427 ms) and each minute (509 ms). The goal is to ensure an harmonious sequence with clearly perceptible sounds. Thanks to these measurements, each completely independent of the others, Gérald Genta Grande Sonnerie models are now all of reliable equal quality. Fine-tuning by the watchmakers is still indispensable, but now converges towards common criteria guaranteeing a unique tune. It takes an average of 12 successive controls to achieve the desired result.
Superior qualityEach Grande Sonnerie watch reacts in its own way, according to the volume occupied by the movement within the case and the corresponding empty spaces; the materials selected and their treatment; the strength of the hammer; as well as a whole host of details such as the quality of the screws, joints and weldings. All these aspects have been meticulously reviewed by Gérald Genta in order to achieve the current degree of perfection based on these trade secrets which it is determined to safeguard. Nonetheless, one feature that can be revealed is that the gongs are now fixed to the side of the case and no longer to the movement, thereby considerably increasing the sound level. The improvements have been made both to the self-winding Grande Sonnerie model belonging to the Octo collection since 2003, and to the hand-wound Grande Sonnerie, an Arena watch introduced in 1999 and bearing the prestigious Poinçon de Genève quality hallmark. The latter is distinguished by its movement beautifully highlighting the striking mechanism through a broad dial opening on the left of the off-set hour and minute display. The back enables one to admire the tourbillon and follow the evolution of the two separate power reserves – 48 hours for the movement, 24 hours for the striking mechanism. A security system locks the crown each time the watch is in the process of chiming, so as to avoid accidentally damaging the striking mechanism.
The key assets of the Arena MetasonicHaving reached the peak of its art in mastering its Grande Sonnerie mechanism, Gérald Genta wished to provide it with a tailor-made case specifically developed to exalt its musicality. To achieve this, it cooperated with a French university in developing a software programme capable of analysing all kinds of materials. Gérald Genta has thereby created a testing system that evaluates a given material’s density, elasticity modulus and loss coefficient, a set of crucial physical parameters that determine the quality of the sound transmission and must be as low as possible.
Material Density(g/cm3) Elastic modulus (GPa) Loss coefficient 100 Index Acoustic Pressure (Force) 100 Index Acoustic Pressure (Melody)
Magsonic® 2.7 71 0.000080 100.0 100.0
Titanium 4.2 110 0.000027 77.6 44.7
Bronze CuSn8 8.2 100 0.000125 63.8 24.8
White gold alloy 15.7 107 0.000100 48.4 35.1
316L steel 8 200 0.000350 37.6 33.1
The first parameter that must be taken into account is density, which must be lower than 5 g/cm3. Among the metals most commonly used in watchmaking, only titanium meets this standard. It is only half as dense as steel, which itself is only half as dense as white gold. In terms of elastic modulus, which is considered to be of superior quality when nearing values below 100 GPa (gigapascals), white gold and titanium come very close to this threshold, whereas the values reached by steel are twice as high. As for the sound transmission loss coefficient, it is precisely measured in laboratory conditions – using calibrated bars that are made to vibrate by laser technology in a vacuum, thus ensuring the absence of any contact as well as free decay of the vibrations - and falls well below the maximum desirable level of 0.0002 as far as white gold and titanium are concerned, but not for steel. Results clearly prove that titanium and gold perform far better than steel, which is not particularly dense but is definitely more sound-absorbing than any other material (high loss coefficient).
Based on the objectives defined for each parameter, Gérald Genta decided to target excellence by creating an alloy of which the composition will remain a closely guarded secret. Duly patented under the name Magsonic®, it displays winning performances with a density of 2.7 g/cm3, an elastic modulus of 71 Gpa and a sound transmission loss coefficient of 0.00008 – meaning respectively 50%, 30% and 60% better than the parameters that were set as objectives. This material is therefore used for the case middle of the brand’s latest Grande Sonnerie model, the Arena Metasonic. The case middle is a crucial element in striking watches, since the sound tends to be diffused in a sideways direction. It is important to choose an appropriate material and to make it as thin as possible. Future owners will be delighted to note that the quality of the sound is even better when the watch is worn, a position in which its back rests against the wrist.
Moreover, Gérald Genta was able to measure the sound intensity (acoustic pressure index, force and melody) produced by various materials by using specific experimental containers. Results show that Magsonic once again surpassed the others, both in force (global sound intensity) and melody (effective intensity of the desired notes: do, re, mi and sol – C, D, E and G).
In addition to the major role played by the Magsonic alloy, this new model also features an original case based on a patented construction inspired by the side drums in a drum kit. The case middle is framed on either side by a bezel and back in grade 5 titanium secured from outside by means of specially designed pillars. This means the sound diffusion is undisturbed by any screws, and results in a highly original creation entirely in tune with the spectacular design characteristic of Gérald Genta models. The entire construction has also been rendered water resistant, because contrary to popular belief, non- watertight watches do not emit a better sound. The latter can even be perturbed by being forced through the bottlenecks created by the passage of air around the winding pushers. Some historical pocket-watches solved the problem by featuring openings spread all around them – a solution naturally unsuitable for wristwatches. The innovations presented here by Gérald Genta are a contemporary response to a desire to raise the bar as never before. They are the first fruits of a particularly ambitious research and development programme, and all-new striking mechanism designs are likely to be introduced in the near future.
A deliberately contemporary styleMeasuring 46mm in diameter at the case middle and 50mm overall, the Arena Metasonic features a combination of vertical-polished and horizontal satin-brushed surfaces. It is fitted with an ostrich leather strap. The crown bears the individual watch number, while the striking mechanism controls serving to switch between Grande Sonnerie (grand strike), Petite Sonnerie (small strike), Minute Repeater and Silence modes are within easy reach on the opposite side. Gérald Genta has adorned the movement with an innovative wave-patterned motif as a nod to the propagation of sound. The jewels are in white sapphire to ensure an ideal visual match with the overall mechanism which exceptionally does not feature the “old gold” surface treatment characteristic of the brand’s signature “Potter finish”. This exceptional watch is also presented in a glass security box which renders it invisible until the owner pushes the biometrically programmed button that will respond to no other touch… The interior then lights up and the watch base is raised to bring it within reach. True magic for a watch blending the best of noble traditions and cutting-edge technologies.
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Respecting the aspects of harmony was an important point. Two crowns were used to keep the beauty of symmetry with. One crown is used for winding and the other for setting time and calendar. Both crowns build the main symmetry axis. Now it was necessary to build the optical balance between the oscillating weight on one side and the indication of time on the other side. For that reason a three dimensional moon was placed between the two barrels, indicating the hours and minutes.
Finally, placed on a turning axis, held by a carrying arm the carriage is rotating around itself. These two synchronized motions create a gyro scoping image immediately taking full attention. 
