Gérald Genta Arena Metasonic

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.

Gérald Genta Arena Metasonic watch

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.

Gérald Genta Arena Metasonic

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 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.

Gérald Genta Arena Metasonic watch movement

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.

PHILIPPE DUFOUR Répétition Minutes Grande et Petite sonnerie

This superlative horology masterpiece is one of the most revered complication watches crafted in Switzerland. The legendary master watchmaker Philippe Dufour created this authentic masterpiece, unveiling the entire mechanism of this grand and small strike minute repeater.

The bezel can even be lifted to admire the screws underneath adorned with hand-enamelled and hand-engraved indications. With a nod to modernity and clarity, the hands are of a different colour than the movement while the hour-circle, with its hour markers and Arabic numerals, has been applied directly to the crystal. The exclusive buckle has been fashioned, piece by piece, by the watchmaker himself.

PHILIPPE DUFOUR Répétition Minutes Grande et Petite sonnerie

Technical details

Hand-wound, 21,600 vph, 35 rubies
38-hour power reserve

Striking mechanism (grand strike, small strike, minute repeater, 24-hour power reserve)

750 (18K) white gold
Hinged bezel, protecting the striking mechanism levers
2 sapphire crystals

Blue applique hour markers and Arabic numerals
Exclusive blued steel hands

Exclusive gold buckle, can be completely dismantled

Credor Spring Drive Sonnerie (Ref GBLQ998) – The First Striking Watch Built By SEIKO

The SEIKO Credor Spring Drive Sonnerie is a classic mechanical wrist watch that features the Hour Striking Function. It is the first striking watch built by the Japanese watch making giant SEIKO.

Introduced in 2006, the Credor Spring Drive Sonnerie (Ref GBLQ998) is a land mark timepiece that adds a golden feather to SEIKO’s unmatched achievements in horology in its 100 years of rich history. This Grande complication model has been derived from the enormous success of Spring Drive, a watch that presents, visually, the pure, natural and continuous motion of time.

The challenge was to express the passage of time in sound as well as by the smooth movement of the hands across the dial. The challenge was taken up by a small and elite team of watch making craftsmen in SEIKO Epson under the leadership of Mr. Kenji Shiohara. This team, “the Micro Artist Studio,” was guided by a shared passion for the creation of distinctively Japanese timepieces which express both the technical skill of SEIKO and the cultural heritage of Japan.

The result is a unique and hugely innovative timepiece which conveys to both eye and ear the serene flow of time. The continuous stream of each second, minute and hour is indicated by the quiet revolution of the glide-motion hands around the dial, and the time is also marked by a unique chime expressed in a softly tinkling “hanging” bell. This bell chime resonates with the cultural heritage of Japan and is instantly recognizable as an auditory symbol of the nation’s centuries of tradition.
Credor Spring Drive Sonnerie (Ref GBLQ998) - The First Striking Watch Built By SEIKOThe watch is built on the base of the ground-breaking Spring Drive movement 7R series with its glide-motion hands and 48 hour power reserve. Onto this Spring Drive movement is added the “sonnerie” mechanism which has its own, entirely separate barrel, ensuring that this mechanism has more than 40 hours of power reserve.

The power reserve is shown on a second indicator at the two o’clock position. The movement is easy to operate with just the one crown at the 3 o’clock position and a mode indicator at 6 o’clock. The movement comprises over 600 individual parts, each uniquely made and, of course, hand assembled and finished to the highest levels of precision.

The Hour Striking Function
The “sonnerie” mechanism has an hour striking function. It is built around typical Japanese hanging bell sound. This was chosen because its unique and lingering sound harmonizes with the natural flow of time and space. Purity of sound was the greatest challenge, and the achievement of the perfect bell sound was made possible by the remarkable combination of a bell system, the use of a newly developed governor and the unique sound escape system that allows the chime sound to pass through the case.

This governor mechanism is a remarkable innovation. It uses the viscosity of air so that the chime sounds at very precise intervals and there is no other sound to interfere with the pure strike of the bell. Combined with the entirely silent Tri-synchro regulator, the absolute silence of the whole movement is ensured and the complete purity of the sound is the delightful result. The hour striking function can be set to one of three different modes: an hourly strike, three hourly strike, or silence. To power the hour striking function, a spring exclusive to this mechanism is used in parallel with the watch mechanism’s barrel.

The hour repeating function announces the current time by chiming each hour when the button located at the 8 o’clock position is pressed. A silent function is included so that chiming can be muted as long as the button located at 8 o’clock position is pressed halfway down. The movement has a “fail-safe” mechanism to prevent the chime sounding when inappropriate actions are performed by mistake.

The Modes
The mechanism offers the following three modes:

1. “Sonnerie” mode: the number of hours is automatically counted by chiming every hour on the hour.
2. “Original” mode: the time is announced by a three-strike chime at the passing of every three hours: 12:00, 3:00, 6:00, and 9:00.
3. “Silent” mode: the chime is disengaged.

These modes can be selected simply by changing the mode indicator.

The Design
As befits a watch of such intricacy and sophistication, the strike hammer is visible through the dual surface curved sapphire crystal. The case itself is crafted from 18-karat pink gold, which not only reflects the value of the movement but assists the purity of the sound of the chime.

On the mainspring barrel of the bell mechanism, a cutout Japanese bellflower (Kikyo flower in Japanese) drifts down on a river, symbolizing the continuous flow of time. The Japanese bellflower is chosen because it is the flower of the city where the Micro Artist Studio is located.

Technical details

  • Case: 18-karat pink gold
  • Band: Crocodile
  • Glass: Dual surface curved sapphire crystal with anti-reflective coating
  • Water resistance: Non water-resistant
  • Size: [Case outside diameter] 43.2mm/[Thickness] 16.0mm
  • Retail price (In 2006): 15 million Japanese Yen (excluding tax and import duty)

Caliber details

Spring Drive Sonnerie caliber, 7R06

  • Hour striking function
  • Three modes selectable: chiming every hour on the hour/chiming every three hours/silent
    Hour repeating function
  • Power reserve indicators: Two. One each for the watch mechanism and the bell mechanism
  • Wind-up method: Manual-winding
  • Time accuracy: Monthly rate within ±15 sec (equivalent to a daily rate of ±1 sec)
  • Power reserve (watch mechanism): Approx. 48 hours
  • Power reserve (bell mechanism): More than 40 hours
  • Number of jewels: 88
  • Movement diameter: 37.0 mm
  • Movement thickness: 7.05 mm
  • 617 components

Production quantity

Limited to five pieces per year.

F.P.Journe Sonnerie Souveraine

The Sonnerie Souveraine timepiece is a high complication mechanical wristwatch that incorporates both Grand-Strike and Minute Repeater functions.

The grand-strike clockwatch is the most complex of horological creations. The greatest difficulty in its construction is to achieve full clockwatch capability from the limited energy in a wristwatch, without compromising on the sound and reliability of the chime.In this watch, a single mainspring provides enough energy for 24 hours of grand strike (96 full chimes in passing), without using the minute-repeater. The chiming functions alone use up almost 60% of the main-spring’s energy, and in silence mode without the chime, the movement is running for five days.

Constructing this movement has been a permanent search to save energy in maximising mechanical efficiency. The result is a low-tension movement with gentle mechanisms that have to be very finely adjusted to ensure unfailing chimes 35,040 times a year.

Operating a chiming watch has always been risky. If you do the slightest thing wrong, like setting the time while the chimes are ringing, you damage precious mechanisms.

10 Patents for the SONNERIE SOUVERAINE
Barrel: A single barrel drives both the going-train and the strike-train from each end of the mainspring.The barrel’s drum, fixed to the outer end of the mainspring coil, has a toothed edge to drive the going train. The barrel’s arbor, fixed to the inner end of the mainspring, turns a toothed wheel that drives the strike-train through unidirectional gearing.

Power reserve indicator: A mainspring that unwinds both through the barrel and the arbor requires a sophisticated power-reserve indicator.The power-reserve indicator has three coaxial differentials. The top differential forms the link between the arbor and the barrel. The lower differential moves according to the winding or unwinding of the arbor. A third differential forms the link between the first two differentials to show the mean power-reserve of the mainspring.

Winding and setting system: The compact winding and setting system does away with the long stem and sliding-pinion, and finds its place under the dial. In this system, the crown-wheel is permanently meshed with the transmission-wheel mounted coaxially on a rocking arm. The winding-stem slides through a square in the centre of the crown-wheel. The transmission-wheel drives intermediate-wheels for winding and for setting the time, mounted at either end of the rocking arm. Pulling out the winding-stem makes the pullout piece pivot the arm to mesh the intermediate-wheels with the minute-wheel for setting the hands. With the stem in the winding position, the torque produced by the winding action on the transmission wheel, swings the rocking arm to mesh intermediate wheel with the winding ratchet.

Strike selection: Controlled by a column wheel, the mechanism to select and indicate the strike mode performs its duties with the minimum of parts. The rotating column-wheel acts on three levers: the lever to select grand strike or small strike, the lever to select silence and the sprung rocking-arm that indicates the selected strike mode on the dial via a rack and pinion. Pressing the strike-select button makes rocking-arm lift the sprung pawl. The pawl pulls the 12-toothed wheel step by step to rotate the column-wheel through consecutive cycles of actions.

The striking racks: The construction of the movement, with the hours and minutes off-centre, allows the striking-racks to be mounted in the centre of the movement. This in turn makes possible outsize racks for greater precision and control. The strike is governed by three coaxially mounted racks: for the hours for the quarters and for the minutes. Each has ratchet toothing to activate the hammers. When the strike is released, the racks drop on their respective cams. They are then immediately engaged by the strike-train and lifted to the end of their travel. As the racks lift, their outer teeth engage the gathering pallets to strike the gongs. The distance each rack is lifted, thus number of teeth presented to activate the strike, depends on its starting point on its cam.

The strike sequence: The hours-rack has a toothed sector where it is engaged by the strike-train. The teeth are permanently meshed with a free pinion, rotating coaxially on the fixed pinion of the strike train. To lift the rack, the rocking clutch-pinion engages the free and fixed pinions, locking them together, and transferring the drive from the strike-train to the rack.When the clutch-pinion disengages, the sprung-rack brings the rack’s finger down on the cam.

Strike release: Every quarter hour, a tooth on the star-wheel pivots the trigger against its spring to set in motion the chime in passing. The trigger acts through sprung levers to disengage the rocking arm from the pivoting clutch. This frees the pinion to allow the racks to fall on their cams. The spring then returns the rocking arm against the pivoting clutch (o re-engage pinion to lift the racks.The minute-repeating strike is released by pressing button. The pivoting levers act on the rocking arm to disengage the clutch and allow the racks to fall.

Chiming gongs: This new design produces a louder, clearer sound from gongs that are just three-tenths of a millimetre thick. Mounting the gongs on the movement instead of around it increases the diameter of the movement.The gongs for a chiming mechanism consist of a flat blade one end of which can be fastened to the structure of the watch. The free part of the blade is shaped so that its natural frequency is audible when its edge is struck.

Blocking the strike automatically: The chimes are automatically blocked to reserve the last 24 hours of the mainspring’s energy to the movement.A cam, working off the power-reserve differential, switches the pivoting lever when the power reserve falls to 24 hours. The blocking device keeps the clutch-pinion meshed with the driving pinions of the rack, thus preventing the racks from falling to start the chime.When the power-reserve exceeds 24 hours, the cam releases the blocking mechanism, returning the pivoting clutch to the control of the rocking arm.

Blocking the strike and the winding stem: This safety system prevents the winding-stem from being pulled out when the strike is operating, and it blocks the strike when the stem is pulled out.

A locking-cam can be pivoted in two positions: one to block the manual strike-release button, the other to lock the winding-stem by acting on. Pulling the winding stem out pushes the lever to the left, pivoting the locking-cam so that it blocks the manual strike-release. The locking cam is also switched by a pivoting sprung arm connected to the hours-rack. As soon as the rack moves to begin the strike, the arm pivots the cam so that it engages the stem-blocking device and prevents the stem from being pulled out to set the time.

Technical Specifications

Caliber 1505
Manually wound
Gold baseplate and bridges
40 jewels

Movement dimensions
Overall diameter: 35.80mm
Casing diameter: 35.00mm
Frame height: 6.25mm
Overall height: 7.80mm
Height of stem axis: 3.41mm
Stem-thread diameter: S1.20mm

Free-sprung; 4 adjustment weights
Flat Anachron balance-spring
Fixed stud-holder
Pinned stud
Spring pinned to the collet
Frequency: 21,600 v/h (3Hz)
Inertia: 11.00 mg/cm2
Angle of lift: 52°

Dial up, fully wound: > 340°
Dial up, 24 hours: > 300°

Linear escapement
15-tooth escape-wheel

Visual indications
Hours and minutes, off-centre Small seconds at 6 o’clock
Power reserve
Strike mode selection
Striking hammers

Sound indications
Grand strike, small strike on the quarters in passing Strike silent
Minute-repeater on demand

120 hours without chime
Approx. 48 hours with grand strike
Approx. 24 hours after strike runs down

Circular grained baseplate
Circular ribbing on the bridges
Polished and bevelled screws
Pegs with rounded, polished ends
Steelwork decorated by hand
3D engraving.

Diameter 42.00mm;Overall height 12.55 mm
Two position winding and setting crown
Pushbutton to release the minute-repeater at 2 o’clock
Pushbutton to select the strike mode at 4 o’clock

Number of pieces
Movements without dial: 408
Cased-up, on leather: 441
Cased-up, steel bracelet: 558