With the introduction of a chiming watch in the classic Royal Oak family, Audemars Piguet may have just created one of the most desirable minute repeater wristwatches around. The Le Brassus brand has quietly unveiled a limited edition Royal Oak Repeater Supersonnerie, a watch that the channels the brand’s unmatched history in making minute repeaters into their most successful model line.

The case is made from titanium with a matching bracelet

The “Supersonnerie” is a minute repeater eight years in the making, intended to offer a slew of technical improvements that AP thinks will make it nothing less than the best-sounding repeater in the world. We first came across it as the RD#1 Concept Acoustic Research Minute Repeater [the Concept watches are where AP showcases their latest R&D breakthroughs, past concepts include the Laptimer and the more recent ultra-thin perpetual calendar].

While its first appearance was in a very futuristic looking watch, the Supersonnerie appeared again in the classically-styled platinum-cased Jules Audemars Minute Repeater Supersonnerie. This year AP introduced the Code 11:59 Supersonnerie, the highlight of a very polarizing new watch family. So in a sense, it was only a matter of time before it showed up in the brand’s much vaunted Royal Oak clothing.

The slider on the case flank is a dead giveaway

The Royal Oak Repeater Supersonnerie uses a titanium case and a matching bracelet. It is 42 mm wide and there are two visual cues that that give away the fact that this is no ordinary Royal Oak – a slider to activate the minute repeater is placed on the side of the case and the presence of a small seconds subdial at 6 o’ clock. The case is 14 mm thick and is water-resistant to 200 meters. The familiar blue dial has the “Grande Tapisserie” pattern and time is indicated by white gold hands and applied hour-markers coated with SuperLuminova.

The watch is powered by the hand-cranked Caliber 2959 consisting of 359 parts and a power reserve of 72 hours. What makes the Supersonnerie unique is the quality of sound when the chiming mechanism does its thing. Normally in a repeater, the block for the gongs is screwed onto the movement plate, on the side of the movement opposite the dial (in repeaters with display backs, the only part of the chiming system that is visible is usually the regulator, the hammers, and the gongs themselves). This means the sound has to travel through the caseback, and that the dial, crystal, and case act as resonating surfaces. The combination of all these factors is what determines the final sound.

A membrane made of titanium covers the back of the movement

In the Supersonnerie, the gongs aren’t attached to the movement plate. Instead, they are attached to a “soundboard” — a membrane made of titanium, which covers the back of the movement. This membrane is held in place by screws and forms a water-tight seal. When the chimes are struck, the membrane acts like the soundboard of a string instrument like a guitar or violin. It has been designed so that its natural frequency closely matches that of the chimes, and it dramatically amplifies the sound of the chimes as well as giving them a clear, pleasing sound. The actual caseback covers the thin, relatively delicate membrane and has apertures along its edge to allow sound to escape. Interestingly, the system works so well that the watch actually sounds louder, with a better tone, when the watch is strapped on the wrist.

The watch is limited to just 20 pieces and as of now is only available with the brand’s Japanese retail partner, Yoshida in Ginza, Tokyo. There is another version that's cased in platinum and presented with a black dial and a leather strap. This one is limited to 20 pieces too. Price is only available on request.