Blancpain creates the magnificent Grande Double Sonnerie in the deep mountains of Switzerland

Blancpain's "Farm" workshop is located in Le Brassus in the Vallée de Joux in Switzerland. Surrounded by coniferous trees, this quiet location produces a magnificent complication watch that is hard to imagine: the Grande Double Sonnerie, a watch capable of playing two melodies.

"Grand Double Sonnerie" with a choice of two melodies

　Blancpain announced the Grande Double Sonnerie in November 2025. This exceptional complication watch features a grand sonnerie that chimes every hour and quarter hour, a petite sonnerie that chimes every hour and half hour, a minute repeater, as well as a perpetual calendar and a flying tourbillon.

　What's surprising is the details of the sonnerie mechanism. The minute repeater is on demand, charging energy by lowering a slider or pressing a push button, and the sonnerie, which must automatically chime every hour, quarter hour, and half hour, is still a difficult watch mechanism to manufacture, even today, despite advances in design support systems and machine tools. However, Blancpain's Grand Double Sonnerie not only features a minute repeater, but also a sonnerie that plays four bars of "The Chimes of Westminster," and even includes a "Blancpain" song written specifically for this film by Eric Singer of KISS.

　This unprecedented feat, combined with Blancpain's signature aesthetic complications, was born in the tranquil Vallée de Joux in Switzerland. Located in this idyllic region, a stark contrast to the complexity of this piece, we visited the R&D, manufacturing, and decoration departments of the brand's complication workshop, "FARM," to unravel the "feature" that made this piece possible.

The path to greatness forged at the farm

　The Grand Double Sonnerie was born approximately eight years after Blancpain President and CEO Marc A. Hayek decided to develop the Grand Sonnerie. Based on 1200 blueprints and 21 patented technologies, the movement is made up of 1053 components, totaling 1116 parts. It was designed, assembled, and decorated at Blancpain's factory. The Grand Sonnerie is a must-see, and the realization of this magnificent mechanism in a practical wristwatch is a testament to its power.

Playing two types of four-note melodies

　A typical minute repeater or sonnerie is equipped with two hammers and a gong. The high and low notes produced by these parts, as well as the number of strikes, determine the time. However, Blancpain was trying to produce a melody, not just a note. To achieve this, they had to prepare hammers and gongs that could produce four notes - E, G, F, and B - and also play the equivalent of two songs. What did the R&D department do to prepare for this challenging challenge?

　The key is the quarter luck (there will be many more "key" words after this...).

　The quarter (or hour) rack of a repeater or sonnerie has teeth equal to the number of minutes it will sound, and the hammer strikes the gong through a pinion that contacts the quarter rack a number of times corresponding to this number of teeth. In contrast, this watch also has teeth for the four notes mentioned above - E, G, F, and B - in order to play a melody. To play a melody, the sound must be at a regular tempo. To maintain a constant tempo, the teeth are fine-tuned by grinding while measuring the frequency of the sound produced by the gong with a special analyzer. If the teeth are ground down too far, the part becomes unusable, so the watchmaker must make extremely meticulous adjustments by hand under a microscope.

Two quarter racks are placed one on top of the other to play two pieces, "The Chimes of Westminster" and "Blancpain." The melody selection for each is done using a slider at 9 o'clock on the side of the case, but internally, switching is done using a column wheel. When the slider is operated, the column wheel moves, and the selected rack plays the programmed scale. The movement's base plate and bridges are made of 18K gold, but the gears, especially those around the sonnerie and repeater, are made of stainless steel. The size of this column wheel is said to be the same as that of a typical chronograph.

To achieve both stable energy supply and beautiful tone

　The regulator (governor) is an essential component in many repeater and sonnerie watches. While various regulators exist to maintain a constant striking speed regardless of the mainspring's winding level, their use of centrifugal force from rapidly rotating weights often interferes with the gong's tone. To preserve the "beautiful tone," Blancpain has adopted a magnetic regulator for this watch. This mechanism generates a magnetic field by rotating two magnetized parts at high speed, and the magnetic fields generated by the magnets in the parts resist each other to regulate the speed. Using a magnetic field, the absence of physical contact eliminates noise, consumes little energy, and allows for precise adjustment of the striking tempo. In 2011, Breguet, a member of the same Swatch Group as Blancpain, adopted this regulator in its "Classique Musicale" watch. While it uses the same patented technology, its design has been optimized for incorporation into the Grande Double Sonnerie's Caliber 15GSQ movement.

　The power reserve of this model's grand sonnerie is approximately 12 hours, and that of the petite sonnerie is approximately 14 hours. Within this duration, in addition to striking the time, the watch must also play a four-bar melody. Currently, most grand sonnerie watches that play the Westminster chimes only play three bars. However, this model fully covers the final four bars. Therefore, at 12:59, the longest strike, the watch must ring for 22 seconds. It's easy to imagine how important the magnetic regulator is for this sonnerie, which must produce a constant tempo regardless of the amount of winding of the mainspring, while consuming a considerable amount of energy.

It's not enough to just ring it

　Blancpain's ingenuity is evident not only in the technology that produces sound, but also in the beautiful tone it produces.

　The gongs in particular are a testament to Blancpain's tireless pursuit of perfection. For chiming watches, and not just for Blancpain, the choice of material for the gongs and case is of paramount importance. 18K gold is the most common, and Blancpain's Grand Sonnerie is also crafted from 18K rose gold. To arrive at the answer, the R&D department tested 11 different raw materials, then selected eight of them for in-depth research. Even when selecting the material, the frequency was measured using an analyzer to accurately capture the desired sound.

　The shape of the gongs is also a patented technology. To produce the four notes, the watch is equipped with four gongs, each with a different cross-section. Two of them (Fa and Si) are integrated, which helps save space. When asked if the gong shape was inspired by products within the Swatch Group or from other companies, the answer was, "We didn't take inspiration from anything; it's a completely new design." The placement of the gongs has also been carefully considered, with the greatest care taken to ensure that the gongs are stacked, but do not cross or touch each other, in order to produce the desired frequency.

　After being decorated, the gongs undergo their final "tuning" process. Just as a guitar is tuned with a screw, they are checked to ensure that they play a precise pitch from a set frequency. Uniquely, tuning is done by carving the cross section of the gong. Of course, the adjustment tools are also made in-house by Blancpain. While the traditional method of manual work is employed, a laser is used to measure the frequency, combining craftsmanship with modern technology.

　In addition to sound quality, volume is also important. The need to produce a sound resonating within an airtight case is one of the reasons why repeaters and sonneries are said to be difficult to manufacture. While there are certainly ways to achieve this by sacrificing water resistance and dust resistance, Blancpain's goal was a practical watch. At the time of the model's announcement and during our visit to the workshop, Hayek stated that he aimed for a "watch that can be worn every day with peace of mind." It was important that this watch be suitable for everyday use, rather than a decorative complication that resembles a work of art. To that end, Blancpain incorporated a thin membrane made of 18K red gold that fits snugly against the case. This membrane picks up the vibrations of the gong like a speaker, transmitting the sound waves as vibrations to the sapphire crystal and bezel, contributing to the creation of a sufficient volume of sound.

　When I listened to the melody of this work after the interview, I was so impressed by how well it resonated that I asked, "How many decibels is this?" I was very impressed by his answer: "Recently, we have stopped evaluating sound in decibels. High and low tones are heard differently, and what is important is how they register in the human ear."

A useful complication watch

　To reiterate, this work pursues practicality despite its ultra-complex world. Not only has this complex mechanism been packed into a usable wristwatch size of 47.0mm in diameter and 14.5mm thick, but it also features the quality control that is characteristic of Blancpain, which has earned it a high reputation for the high quality of its products.

　For example, after the movement of this watch is adjusted and assembled, it is tested for reliability using a special machine. This test is broadly divided into an "aging test" and an "impact test." Assuming a five-year wear period, the chiming mainspring is wound more than 7000 times, and although the gong is not sounded, the hammer continues to operate. A shock of 1300 g is also tested to ensure it will not break.

　I was also amazed by the meticulousness with which the movement was "assembled twice." The chiming mechanism of this movement was adjusted, and all parts were decorated and reassembled, then disassembled, cleaned, and reassembled. At Blancpain, movements with many springs are generally reassembled twice. However, this movement uses around 50 springs, so the reassembly process is by far the most important, even among Blancpain's complication watches.

　It is also worth noting that five safety systems are in place to prevent malfunctions common to complications: those related to the winding shaft (cancel the time-setting function while the chimes are striking) and (disable striking while the time is being set), those related to the melody selection pushers (lock the melody selection pushers while they are striking) and (disable striking while the melody selection pushers are operating), and those related to the striking power reserve (disable any chimes if the chiming power reserve is insufficient) unless the chiming mainspring is wound.

Blancpain's unique character lies in its beauty

　The main attraction of this watch was the grand sonnerie mechanism, so the focus of the coverage was on the technology behind this part, but the other mechanisms and finishes were also exceptional. In particular, Blancpain's pursuit of aesthetics, one of its greatest strengths, was outstanding.

　This model is equipped with a perpetual calendar, which requires a high level of technical skill along with the chiming mechanism. Previous Blancpain perpetual calendars have been realized by incorporating a module into the base movement, but this model has been newly developed as an integrated unit to fit within a reasonable wristwatch size. Blancpain, which specializes in classic watches, likely felt that a watch that protrudes too far from the wrist would not be aesthetically pleasing. The retrograde calendar display, which was adopted to save space, does not interfere with the internal mechanism visible through the hollowed-out bridge, resulting in a clean design.

　Furthermore, it is also equipped with a flying tourbillon, one of the "Six Masterpieces," which has been a feature since the "Tourbillon" was released in 1989. Many watch enthusiasts will surely find this design, which allows the escape wheel and other escapement regulators to be effectively viewed by offsetting the balance wheel, to be distinctively Blancpain.

　All 1053 parts of the movement, including those that cannot be seen, are finished in a way that is typical of a high-end watch, which further stimulates the desire to own this watch.

　A total of seven craftsmen work on the decoration at the farm, and many of the processes are completed by hand under strict specifications, with each watch taking approximately 460 hours to decorate.

　Nowadays, CNC machining and finishing are commonplace in luxury watches, but the interior corners of metal parts like Blancpain's, which often have complex shapes, can only be carved by hand. Also, rounded edges with sharp corners, which cannot be achieved by machine finishing, can only be achieved by hand.

　The strict requirements extend to the size of the circular graining and the width of the Côtes de Genève. Because of the strictly regulated decoration, even when many parts are gathered together, each one has a strong presence.

Watchmaking history continues in Le Brassus

　We interviewed and reported on the Grand Double Sonnerie, created by Blancpain, from its workshop, "Farm," located in Le Brassus, Switzerland.

　The astonishing mechanism and aesthetic of this watch were created in the quiet mountains. Achieving great work in such tranquility is typical of Blancpain. While never conspicuously flashy, the brand has steadily evolved, while also constantly refining its traditional decorative techniques befitting a luxury watch. The high-quality watches produced from this approach continue to attract the discerning watch enthusiasts of Japan.

　In Le Brassus, where the snow is already deep, Blancpain's watchmakers are hard at work today, and their great work will surely continue for many years to come.