The acoustical qualities of the Master Minute Repeater Antoine LeCoultre surpass all expectations. Its crystalline chime, which has an exceptional purity and intensity of sound, is the fruit of an extraordinary collaboration between stars of the music world and the watchmakers and technicians of the Jaeger-LeCoultre Manufacture. In addition, its manually-wound mechanism is endowed with an astonishing 15-day (360-hour) power reserve, proudly shown off in a dial display, as well as a torque indicator. This masterpiece of refinement and sophistication has an openwork face which reveals the harmonious workings operation of the repeater mechanism and comes in a limited edition of 200 in platinum 950.

Watches that by their very existence throw downpose a challenge to unanimously respected horological principles can be counted on the fingers of one hand. The Master Minute Repeater Antoine LeCoultre is one such creation. First impressions do not deceive with this worthy exemplar of the Master Control line whose classic and elegant design has become a byword for good horological breeding.

Uniquely combining an exceptional level of watchmaking excellence with musical qualities that make it the equal of the most prestigious musical instruments, it is a perfect illustration of the Manufacture's philosophy. The engineers and watchmakers of the Le Sentier Manufacture have pulled out all the stops this time. As ever, they began by mastering the time-honoured techniques of yesteryear and then went beyond them, drawing on contemporary methods and technologies in order to break through the barriers that had limited the creations of bygone eras.

A Feat of Watchmaking Skill
The technical challenge of a repeater watch lies in creating a mechanism capable of reading the time on the watch hands and then translating it into a series of tones that chime out the hours, quarter-hours and minutes. The minute repeater's barrel spring stores up the requisite energy while the hour, quarter and minute rakes racks so named because of their serried teeth are engaged and fall into position. An ingenious decoupling disconnecting-gear system makes it possible to disable the chime wheel and the centrifugal regulator while this happens. The two gongstimbres' hammers then move out of position to let the rakes racks through hence the reason for never resetting a repeater mechanism while it is ringing.

Next, the energy from the barrel spring is released and a regulator acts to ensure a constant speed in the striking of the gongtimbre hammers, made possible by means of the friction of jewels against a polished nickel-silver surface, which ensures that no parasytic excess noise is created.

Sound quality is heavily dependent on the brevity and precision of the striking motion. If the hammer remains in contact with the timbre gong for longer than is necessary, the resulting vibrations will be severely affected and the quality of the sound will suffer accordingly. The adjustment of the hammer is one of the key and most delicate elements in the creation of a high-quality minute repeater.
To underline the richness and quality of their work, Jaeger-LeCoultre's engineers decided to make the deck plate and bridges of the hand-decorated Jaeger-LeCoultre Calibre 947 out of nickel silver.

This wondrous movement is endowed with the most capacious power reserve of any existing watch with complications 15 days. This guarantees a lengthy period during which the watch works with absolute precision (12 days) and so liberates the watch's fortunate owner from the responsibility of having to remember to rewind his precious timepiece every day.

There is another surprise: the Jaeger-LeCoultre Calibre 947 comes equipped with a mechanism to measure the torque in the barrels. Offering a complementary function to the more standard power reserve indicator, this torque-meter gives visual expression to the period in which the watch is working with optimum precision. This display is all the more important owing thanks to the generosity of the power reserve. The amplitude of the balance wheel is directly governed by the torque. A constant torque ensures a constant amplitude in any given position and therefore optimum precision.

Not content with achieving this extraordinary watchmaking feat, Jaeger-LeCoultre also made a point of improving considerably another key aspect of the repeater watch: its sound. There was a limit to the acoustical knowledge of even the most musical of the Manufacture's watchmakers and engineers.
It was therefore necessary to call in acknwledged known specialists in the field and, in particular, a conductor who worked closely with those in charge of the project in order to endowed the Master Minute Repeater Antoine LeCoultre with a sound of a richness and purity unprecedented in a wristwatch. As is often the case when masters from different disciplines pool their talents, the results exceeded all realistic expectations.

Naturally, experience told the watchmakers that it was essential to determine as precisely as possible the exact spot where the hammers should strike the timbre’s gongs. Traditional wisdom has it that this should be as close as possible to the timbre's gongs fastening in order to produce the most perfect sound possible. More exacting research revealed that the ideal point of contact depended on the timbre's gong's dimensions.

Another important detail: a timbre gong does not ring, it vibrates. Unlike a bell which, as everyone knows, rings and therefore transmits itself by means of air waves, a timbre gong merely vibrates. This resolved once and for all the old problem of trying to waterproof a minute repeater: the case does not need to emit a sound but rather a vibration, so that the element that turns vibration into sound can actually be positioned on the outside of the case.

Furthermore, in order to ensure that all of the timbre's gong's vibrations are released instead of being reabsorbed into the timbre gong itself, thereby polluting the purity of the sound, the materials used for the its fastening need to transmit the vibrations at a greater speed than the timbre gong itself.

Since the timbres gongs are made of steel, the choice of materials was limited: aside from steel itself, only quartz, sapphire, beryllium and diamond had the necessary qualities. That is why the technicians chose sapphire crystal to act as the sound transmitter on the Master Minute Repeater, using the latest technology to weld the stainless-steel heel of the timbres gong onto it in order cut out vibration loss.


All measurements were made using a traditional microphone, positioned at a set distance from the sound source, as well as a laser to cut out ambient interference.

The specialist team at Jaeger-LeCoultre worked tirelessly to define and then refine each of these parameters. The result is astonishing. The Master Minute Repeater Antoine LeCoultre produces a tone of unprecedented quality. At over 55 decibels and with durations of over 600 milliseconds and a richness of seven partials, the sound produced exceeds anything previously achieved by a wristwatch. Even those with a comparatively unmusical ear will recognise and appreciate the difference immediately.


The spirit of Antoine LeCoultre
A tireless quest for perfection: the whole history of Jaeger-LeCoultre can be summed up in this simple phrase. The name of the Manufacture's great founder, Antoine LeCoultre (b. 1803), could only be legitimately invoked in connection with a creation of the greatest virtuosity which combined the best of traditional approaches with the avant-garde innovations of a new generation of watchmakers. In the Master Minute Repeater Antoine LeCoultre the exceptional becomes the rule, and extraordinary watchmaking prowess is coupled with musical research in a way that is only really conceivable in the legendary Le Sentier Manufacture, where all the arts and skills of watchmaking are still practised.


A complication to enchant watch connoisseurs
Repeater watches were invented in the days before electric light in order to provide an acoustic indication of the progress of the hours during the night. The charm of being able to hear the striking of the hours, quarter-hours and minutes on demand, however, was such that the minute repeater quickly established itself as one of the favourite complications among connoisseurs of Haute Horlogerie.

With the Master Minute Repeater Antoine LeCoultre, the story of repeater movements has reached a new high a timepiece of such extraordinary mechanical, aesthetic and acoustic refinement could only have been conceived and brought to life within the Manufacture that, since its foundation, has devoted itself indefatigably tirelessly to the pursuit of perfection.

Jaeger-LeCoultre Master Minute Repeater Antoine LeCoultre:

The Technical characteristics
Movement:
• manually wound mechanical manually-wound movement, the Jaeger-LeCoultre Calibre Jaeger-LeCoultre 947, made crafted and decorated by hand
• 21,600 vibrations an per hour
• 15-day power reserve, double barrel parts
• 41 jewels
• 8.95 mm high

Functions:
• hours, minutes
• power reserve
• barrel torque indicator
• minute repeater

Dial:
openwork silvered sunray-patterned, revealing the movement, applied numerals and hour-markers in rhodium-plated gold,12 luminescent dots

Hands:
• hours and minutes: alpha in rhodium-plated brass
• others: rhodium-plated brass, blue varnish

Crown:
1 crown to start the watch and set the hours and minutes
1 sliding bolt to activate the minute-repeater function

Case:
• 44 mm in platinum 950, in a limited edition of 200
• cambered sapphire crystal, hardness n°9
• sapphire crystal base case-back revealing through which the movement can be viewed
• water -resistant to 50 metres

Strap:
• matt grey alligator leather 22/18 and 18 mm folding buckle clasp in platinum 950

Reference:
• platinum 950: 164 64 20