The Grande Double Sonnerie is Blancpain’s most ambitious wristwatch to date, a fully integrated grand complication that combines a double‑melody grande sonnerie, petite sonnerie, minute repeater, flying tourbillon and retrograde perpetual calendar within a wearable red or white gold case. It crowns decades of the manufacture’s work on striking watches and grand complications and pushes that lineage decisively into new territory, both acoustically and technically.
Architectural, revealing
The Grande Double Sonnerie presents its mechanical complexity on the dial side in a way that is open, structured and legible rather than theatrical for its own sake. The entire dial architecture is built around a 5N red gold base, with the time and calendar indications effectively framing the visible sonnerie and tourbillon works beneath.
The hours and minutes are displayed centrally with leaf‑shaped hands in blackened gold. Around them, a ring of polished blackened gold indexes sits on a sunray‑finished black‑rhodium surface, which reads as a dark, slightly metallic halo that contrasts crisply with the warm gold of the movement underneath. The choice of black rhodium on the dial ring and blackened gold for the hands and indexes ensures excellent legibility while echoing the dark tone of the strike-work components that sit deeper in the movement.
On the right side of the dial, Blancpain has positioned two 5N gold subdials with circular satin finishing. The upper subdial is devoted to the day of the week, the lower to the month and leap‑year indication; both use baton‑style hands in blackened gold and peripheral scales, leaving as much of the underlying mechanics visible as possible. On the left, a broad retrograde date arc in 5N gold with circular satin finish and black numerals sweeps along the perimeter, its serpentine hand pivoting from near the centre of the movement. This configuration frees the central visual field so the four hammers of the sonnerie and the flying tourbillon can be seen working without being obscured by calendar disks or plates.
Two further indicators complete the functional display without disturbing the balance. There are separate power‑reserve indications for the going train and for the chiming mechanism, ensuring the owner always knows the available autonomy for both timekeeping and striking. In addition, a dedicated small aperture shows when the sonnerie is blocked during time‑setting, a subtle but important interface for a complication of this complexity.
All calendar scales and the retrograde date track can be customised in terms of colour and language, underlining the bespoke character of each piece. Gold cabochons in 5N punctuate and visually anchor the composition. Overall, the dial is not a separate decorative element but an architectural frame integrated into the movement, with its materials, colours and finishes designed to highlight the depth and sophistication of the calibre 15GSQ.
Calibre 15GSQ – construction, specifications and acoustic innovations
At the heart of the Grande Double Sonnerie is the new hand‑wound calibre 15GSQ, a fully integrated movement comprising 1,053 components out of a total of 1,116 for the watch, developed over eight years and 1,200 technical drawings. It is built on a single mainplate with no modular calendar or sonnerie plate stacked on top, an approach that is extremely rare in the realm of wristwatch grand complications and essential to the open‑dial concept.
The movement measures 35.80 mm in diameter and 8.50 mm in height, runs at a frequency of 4 Hz and contains 67 jewels. Two mainspring barrels are fitted: one dedicated to the going train, providing a 96‑hour power reserve, and a second devoted to the chiming functions, providing approximately 12 hours of autonomy in grande sonnerie mode. Winding is manual in both directions.
Grande sonnerie, petite sonnerie and minute repeater
Functionally, the watch offers grande sonnerie, petite sonnerie and minute repeater. In grande sonnerie mode it sounds the hours and then the quarters in passing, on every full hour and quarter‑hour. In petite sonnerie, it sounds the hours on the hour and the quarters on the quarters without repeating the hours. The minute repeater can be activated on demand, but in contrast to traditional designs it draws its energy from the sonnerie barrel, without the need for arming via a slide.
The defining feature is that all quarter‑hour soundings are built not on the usual two‑note ding‑dong pattern but on a four‑note melodic structure using Mi, Sol, Fa and Si. This requires four distinct hammers, each associated with its own gold sounding ring. The choice of gold for the gongs follows extensive testing of different materials and profiles; gold provided the most refined, rich and harmonically balanced acoustic result when coupled with a gold case.
The movement plays two different four‑note melodies, Westminster and a second composition named Blancpain, the latter created specifically for this watch by Eric Singer in collaboration with Derek Sherinian. Both use the same four notes and the same tempo, but in different sequences. Selection between Westminster and Blancpain is made via a case pusher that acts on a column‑wheel‑controlled mechanism.
To enable two melodies within the confines of a wristwatch, Blancpain’s constructors superposed two separate pièces des quarts, each with its own pattern of teeth corresponding to one of the melodies, rigidly attached one atop the other. The four hammer levers (lèves) are fitted with two levels of arms. A dedicated rocking mechanism, the bascule de changement de mélodie, shifts which level of arms engages with which level of the pièces des quarts, effectively selecting which tooth pattern – and thus which melody – is read during each striking sequence. This construction is one of the key technical signatures of the calibre.
Unlike other wristwatch grande sonneries, which on the full hour generally chime only the hours, the Grande Double Sonnerie sounds both the hours and all four quarters, giving the owner a complete rendition of the chosen melody every hour. This extended sequence demands careful energy management and is one of the reasons the chiming barrel and regulator design were so thoroughly rethought.
Acoustic tuning, membrane and magnetic regulator
Because the movement composes genuine melodies, the tolerances for pitch and tempo are far narrower than in a two‑tone repeater. Each gong is profiled and cut so that its principal vibrational mode corresponds to the target frequency for its assigned note within an audible range that is both clearly perceptible and pleasant. After rough profiling, the watchmaker performs micro‑adjustments to the length and section of each gong and validates the resulting frequencies using laser‑based measurement, tuning them until the measured frequencies fall exactly into the desired values for Mi, Sol, Fa and Si.
The tempo is governed by a patented magnetic regulator. Instead of the traditional anchor or centrifugal governors, Blancpain uses rotating metallic elements that move within a magnetic field. As the speed increases, centrifugal force draws the elements into zones of higher magnetic resistance, slowing them; as torque drops and the elements tend to slow, springs pull them back into zones of lower magnetic resistance. The result is a constant rotational speed with significantly reduced energy consumption and no mechanical contact noise. The regulator is effectively silent, ensuring that only the chimes are heard.
Together with this regulator, Blancpain specifies an extraordinarily tight tempo tolerance for the melody. The intervals between notes are measured and adjusted to within around a tenth of a second, with the tooth profiles of the pièces des quarts and the tips of the hammer levers being shaped and corrected in increments on the order of microns so that each hammer strikes at precisely the right instant.
To enhance projection and tonal balance, Blancpain has developed an acoustic membrane in red gold integrated beneath the bezel. This thin membrane is solidly coupled to the gongs and crystal and allowed a degree of vibrational freedom. It acts as an acoustic coupler and diffuser, reinforcing lower frequencies that would otherwise be damped by the sapphire and bezel and smoothing the overall timbre. This membrane–bezel system is among the 13 patents embodied in the final construction.
Retrograde perpetual calendar, integrated
The perpetual calendar is not an add‑on plate but fully integrated into the calibre. The core of the system remains the classic triad of a 24‑hour wheel, a 12‑month programme cam and a four‑year leap‑year cam, but the date indication is realised as a retrograde hand sweeping a broad arc on the left side of the dial. At the end of each month, the date hand snaps back directly to 1 in about 20 milliseconds, without passing through fictitious dates for shorter months. A dedicated spring is progressively armed as the hand advances day by day and released at month‑end, with a shock‑absorbing system ensuring that the return is brisk yet controlled and that the hand stops precisely at the 1 marker rather than overshooting.
The day and the dual month/leap‑year indications are displayed on two open subdials positioned on the right, each using an external ring scale and leaving the centre open. This arrangement, combined with the retrograde date on the left, permits a calendar display that is both complete and visually light, preserving a clear view of the sonnerie hammers and the tourbillon.
Blancpain’s signature under‑lug correctors, which allow fingertip adjustment without tools, have been re‑engineered for this calibre. Because the acoustic membrane occupies the usual interface between case and movement, the correctors – and, critically, their return springs – have been moved into the movement itself, an unprecedented solution that maintains the convenience and clean case flanks of the Villeret line while adapting to the specific architecture of the Grande Double Sonnerie. As in Blancpain’s other complicated calendars, the mechanism incorporates security systems that prevent damage if the owner attempts to adjust indications during an automatic date change.
Flying tourbillon and regulating organ
The tourbillon is Blancpain’s emblematic flying construction first introduced in 1989 and here adapted to the 15GSQ. The assembly is supported only from below, without an upper bridge, giving an unobstructed view of the carriage, balance and escapement and accentuating the sense that the cage is floating above the dial. For this movement, the tourbillon frequency has been increased from 3 Hz to 4 Hz, in line with the higher beat of the calibre, and the balance spring is made of silicon.
The silicon spiral brings several concrete advantages: resistance to magnetic fields, reduced mass, the ability to realise an optimised geometry and better isochronism across the working range of the mainspring. Together with the 4 Hz frequency, this should provide a stable and contemporary level of chronometric performance even within the context of a highly complex striking movement. The tourbillon cage itself is finely finished, with mirror‑polished surfaces that catch and reflect the light, and has been slightly elevated above its dial‑side aperture to enhance visibility.
Safety systems
Given the complexity and the cost of a mishandled strike‑work, Blancpain has devoted significant engineering effort to safety. The calibre features five distinct safety mechanisms designed to protect the movement from incorrect handling or momentary inattention.
During chiming, whether in grande sonnerie, petite sonnerie or minute repeater mode, the time‑setting function is decoupled from the movement via a clutch so that the crown cannot alter the indication or stress the mechanism while the strike‑work is engaged. Conversely, when the crown is in the time‑setting position, an on‑dial symbol indicates that the sonnerie is blocked, preventing it from sounding. The chiming mechanism is also inhibited if the power reserve in the strike barrel falls below a defined threshold, with a blocked indicator appearing in its aperture.
Additional interlocks ensure that the melody selection button cannot be actuated while the sonnerie is sounding, and that the sonnerie cannot launch a strike while the melody switching mechanism is in motion. Together, these systems create a robust envelope within which the owner can enjoy the watch without fear of accidental damage.
Decoration and finishing
Where the calibre distinguishes itself as a piece of traditional haute horlogerie is not only in construction but in its finishing. Blancpain has elected to craft both the mainplate and the 26 bridges in 18 ct gold rather than brass or German silver. This choice is visually striking – the movement has a warm, saturated glow that reads immediately through the dial apertures and caseback – but it also raises the bar for the finishing team, as gold’s softness leaves no margin for error.
The mainplate is divided into numerous zones, most of which are decorated with perlage. Unlike the usual practice of applying a single size of perlage across a surface, Blancpain’s finishers adjust the diameter of the circular graining to harmonise with each zone, using four different sizes in total. One of these is so fine, about 0.7 mm in diameter, that it requires a specially hand‑carved tip, not available from standard suppliers. Before the perlage is applied, the plate receives an underlying satin finish, providing a subtly different texture beneath the overlapping circles and contributing to the depth of the final effect.
Côtes de Genève on the bridges are executed using a pierre carbone cylinder instead of the more common abrasive paper‑wrapped drum. The solid stone requires four or five passes per stripe, each removing approximately five microns, and demands extremely consistent movement from the craftsman to maintain uniform spacing and definition, but the result is sharper ribs and a finer grain between them. The difference is visible under magnification: the stripes are crisp and even without the slightly soft edges or waviness associated with worn abrasive paper.
Anglage is performed in the most traditional and labour‑intensive manner. Edges are first cut with a burin to a bevel of around 30 degrees, a shallower angle than the 45 degrees often used elsewhere, chosen to enhance the visibility of the bevel and to avoid unwanted reflections on neighbouring surfaces. This is followed by successive polishing stages using wooden tools charged with progressively finer abrasives, down to powders in the range of 1 micron, and finally by polishing with the stems of gentian, a plant harvested locally in the Vallée de Joux. The result is a luminous, uniform bevel with a soft, almost liquid sheen.
Critically, the bridges and mainplate feature an abundance of sharp interior angles, angles rentrants, which cannot be produced with rotary tools. The movement incorporates 135 such inward angles, each one implying fully hand‑executed anglage with careful carving and polishing at the point where two bevels meet. For an informed observer, these angles are the clearest visual signature of the level of handwork invested.
Steel components such as the sonnerie hammers and the tourbillon upper bridge receive true mirror polishing (poli miroir) on their functional and visible faces. This is carried out on ultra‑flat zinc or modified blocks with cross‑scored surfaces that trap particles, using very fine diamond pastes, and judged by feel as much as by sight, with the craftsman sensing the point at which the component begins to adhere to the block. Flat steel elements are finished with straight graining (traits tirés) or circular satinage as appropriate, always applied in a direction that respects the geometry of the part.
Countersinks for screws and jewels are polished with cherry wood, producing bright, reflective chamfers that set off the heads of the screws and the rubies. Even the gold gongs, whose primary role is acoustic, receive a finely controlled satin finish, obtained by rotating them by hand under an abrasive tool using a specific holder so that the grain follows the curve of the ring.
In keeping with Blancpain’s philosophy, all of this finishing is executed on both the visible and hidden surfaces of components. The movement carries a gold plaque engraved on the dial side with the Blancpain name, and on the reverse with the personal signature of the watchmaker – either Romain or Yoann – who has assembled the watch from start to finish. That signature is normally visible only to the assembler and to any watchmaker who services the piece in the future, an internal acknowledgement of authorship and responsibility.
A familiar encasing
The Grande Double Sonnerie is housed in a substantial yet carefully proportioned red or white gold case that has been engineered as much for acoustics and wearability as for appearance. The diameter is 47.00 mm, with a thickness of 14.50 mm and a lug‑to‑lug measurement of 54.60 mm. Lug width is 23.00 mm. Water resistance is rated to 1 bar, equivalent to 10 metres, appropriate for a chiming grand complication equipped with an acoustic membrane. Both the front crystal and caseback are sapphire, the latter offering a full view of the gold mainplate, bridges and strike‑work from the movement side. The bezel integrates the aforementioned red gold acoustic membrane, which is structurally and acoustically coupled to the case and crystal while retaining enough freedom to vibrate efficiently.
The case construction accommodates Blancpain’s under‑lug correctors without breaking the flanks with dimples or recessed pushers, preserving a clean round profile in line with the classical Villeret aesthetic. Sonnerie mode and melody selection are controlled by a combination of sliding or pushing elements, including the column‑wheel‑linked pusher that toggles between Westminster and Blancpain melodies, all designed with a smooth, positive feel reflecting the quality of the underlying mechanisms.
Straps are alligator leather, available in the colour of the client’s choice, fitted with a gold folding clasp matching the case metal. Production is capped at two watches per year, effectively rendering the piece a quasi‑unique proposition in practice.
The presentation box is not an afterthought. It is crafted from wood sourced from the Risoud forest in the Vallée de Joux, historically renowned for spruce suitable for musical instruments. This timber is prized by luthiers for its resonance properties. In the context of the Grande Double Sonnerie, the box acts as a natural soundboard that amplifies the watch’s chimes when it is struck inside, linking the sonnerie to the valley’s cultural and acoustic heritage.
The most complicated watch the manufacture has ever produced
The Grande Double Sonnerie stands at the apex of Blancpain’s contemporary watchmaking. It is objectively the most complicated watch the manufacture has ever produced, surpassing the 1735 in part count and certainly in acoustic ambition, yet it remains anchored in principles that have defined the brand’s grand complications since the late twentieth century: fully integrated construction, respect for classical complications, and an insistence that a grand complication should be a watch to wear, not a static object condemned to a safe.
Technically, calibre 15GSQ advances the field of striking wristwatches on several fronts: a four‑note sonnerie capable of playing two selectable melodies; a chiming sequence on the hour that includes all four quarters; a silent magnetic regulator and acoustic membrane that together refine both tempo and timbre; a perpetual calendar integrated into the movement rather than layered above it; and a flying tourbillon updated to 4 Hz with a silicon balance spring. Surrounding these are multiple safety systems that make daily use feasible, even for an owner who is not a trained watchmaker.
Aesthetically and in terms of craft, the watch is a manifesto. The decision to build the movement architecture in gold, the density of hand‑executed details – from the 135 inward angles in the anglage to the micro‑perlage zones and pierre carbone Geneva stripes – and the insistence on finishing hidden surfaces to the same standard as visible ones place the piece firmly in the realm of haute horlogerie rather than industrial prestige. The involvement of Eric Singer and Derek Sherinian in composing the Blancpain melody, and the use of Risoud resonance wood for the presentation box, weave in threads from music and local tradition in a way that feels coherent with the watch’s raison d’être rather than cosmetic.
From a critical perspective, the dimensions and the complexity make the Grande Double Sonnerie a highly specialised object. It is not a discreet daily wearer in the conventional sense and demands a wrist and lifestyle that can accommodate a 47 mm chiming grand complication. However, judged by the criteria appropriate to its category – innovation in sonnerie construction, integration of multiple high complications, quality of execution, and acoustic and visual impact – it is difficult to see it as anything other than a milestone, both for Blancpain and for contemporary high watchmaking. It is a watch conceived not as a commercial extension of a collection but as a culminating project; one in which the movement designers, finishers and watchmakers have been given latitude to push their disciplines as far as the brief and physics allow.
In that sense, the Grande Double Sonnerie closes a historical circle begun with the 1735 while opening a new chapter for chiming wristwatches, where the sounding of time is not only preserved but recomposed as music, in gold, at the scale of the wrist.
Blancpain Grande Double Sonnerie Technical Specifications
Reference: 15GSQ 1513 55B / 15GSQ 3613 55B – Production limited to two timepieces a year.
Movement
- Calibre: 15GSQ
- Functions: Hours, minutes, grande sonnerie with two melodies (Westminster and Blancpain), petite sonnerie, minute repeater, flying tourbillon at 4 Hz with silicon balance spring, perpetual calendar (day, month, leap year, retrograde date), power reserve indicators for both the movement and the chiming mechanism
- Winding: Manual winding in both directions
- Power Reserve: 96 hours
- Striking power reserve: 12 hours in Grande Sonnerie mode
- Dimensions: 35.80 mm × 8.50 mm
- Frequency: 4 Hz
- Jewels: 67
- Number of components: 1,053 for the movement (total watch: 1,116 components)
Case
- Material: Red or white gold
- Crystal and Case Back: Sapphire crystal
- Water Resistance: 1 bar / 10 m
- Diameter: 47.00 mm
- Thickness: 14.50 mm
- Lug to lug: 54.60 mm
- Lug width: 23.00 mm
Dial
- Main material: 5N gold
- Indexes: Sunray black rhodium, polished black gold indexes
- Day and month subdials: 5N gold, circular satin finish
- Date display: 5N gold, circular satin finish with black numeral
- Cabochons: 5N gold
Hands
- Hours and minutes: Leaf-shaped hands in blackened gold
- Subdial hands: Baton-style in blackened gold
- Indexes: Polished blackened gold
Straps
- Alligator leather, colour of choice
- Clasp: Folding clasp in gold
