A Technical Perspective – New Gadgets to Optimize Minute Repeaters

Repeater clocks have been invented nicely earlier than electrical lighting, so as to have the ability to seek the advice of the time in the dark. By activating a set off or a pusher, a repeater chimes the time on demand and is usually regarded, and rightfully so, as one of many pinnacles of mechanical watchmaking. Dozens of parts, manufactured to precise tolerances, have to be mixed to orchestrate these extraordinarily complicated mechanisms. The standard of a minute repeater can also be judged by the sound that it produces. Watchmakers pay utmost consideration to their acoustic high quality, patiently adjusting numerous parameters to succeed in the loudest, clearest and richest sound attainable. The tempo of the chime or the eventual background noise (the buzzing noise produced by the regulator) are additionally notably necessary. Of their quest to provide the final word minute repeater, watchmakers conduct sound analysis applications to optimise the chime of their watches.

In a minute repeater, sound is more often than not produced by small hammers placing gongs. Historically made from hardened metal and coiled across the periphery of the motion, the fabric used to craft the gongs, their form and their size (cathedral gongs wrap across the motion nearly twice to provide a richer sound) are essential components. And similar to a musical instrument, the gongs should even be tuned. In fact, the work on sound optimisation consists of many different parameters, together with the case (its form and materials) and the crystal of the watch: every little thing is related.

Previously few years, there have been some fascinating improvements. It began in 2005 when Jaeger-LeCoultre patented crystal gongs that have been immediately soldered to the crystal of the watch, which in flip, acted as an amplifier. The model additionally developed square-profile gongs and articulated hammers to make sure extra constant and highly effective strikes.

The Audemars Piguet Supersonnerie

In 2015, Audemars Piguet offered the Royal Oak Idea RD#1 Supersonnerie with a model new idea for the development of the case and improvements on all ranges of the motion, which will probably be out there within the assortment a yr later, with the Royal Oak Idea Supersonnerie (ref. 26577TI).

The Supersonnerie mechanism endows this new minute repeater mannequin with the amount and resonance often related to pocket watches. This patented expertise outcomes from 8 years of analysis in collaboration with EPFL, the Swiss Federal Institute of Know-how in Lausanne. Impressed by the sonic energy of older minute repeater watches in addition to by the concord of musical devices, a devoted group of watchmakers, technicians, teachers and musicians reviewed the case building to provide a brand new chiming expertise. It has since been utilized to an much more complicated Grande Sonnerie Carillon.

Behind the Supersonnerie idea are a number of vibrant concepts. First is the general building of the watch, which has been imagined as a musical instrument, to be extra exact, like an acoustic guitar. It implies that the gongs behave just like the strings, the hammers just like the participant’s finger and the interior soundboard – a brand new aspect seen via the slots on the caseback – acts because the instrument’s physique and helps to amplify the sound. However there’s greater than the amplifying building of the case. For example, AP has labored on a brand new methodology for pre-preparing the metal used to create the gong construction to attain a singular sound. By finding out the alloy composition, the fabric cross-section, the heating course of, the size and rigidity of the gongs, AP has managed to enhance the readability and musicality of the chimes.

One other necessary enchancment with Supersonnerie comes from the development of the chiming components. In a conventional chiming watch, the gongs are fastened to the motion’s mainplate. Within the Supersonnerie watches, the coiled gongs are connected to a brand new system, a cloth unfold beneath the motion that acts as a soundboard – because of a particular alloy that vibrates greatest. Now, the gongs transmit vibrations on to the soundboard and to not the mainplate, thus bettering the sound high quality, the tone and the amplification of the sound.

Lastly, Audemars Piguet has been engaged on an necessary mechanical aspect of a chiming watch often called the placing regulator. Also called a governor, it units the tempo of the placing sequence of hours, quarters and minutes. It has been completely redesigned to be extra versatile and thus turns into a shock absorber in order that undesirable shock noises are eradicated. This helps to scale back mechanical noises that may degrade the standard of the chimes heard by the wearer of the watch. In case you mix these components, the sound turns into clearer, richer, brighter and louder too, because of the amplifying building.

The Chopard Full Strike

Introduced in 2016, the Chopard Full Strike chimes the time on sapphire gongs which might be an integral a part of the watch glass. The sapphire crystal of the watch and the gongs are machined in a single piece from a block of sapphire. Since fractures in materials are detrimental to the transmission of acoustic waves, the sapphire creates an ideal loudspeaker to diffuse the sound of the strikes. The depth of the sound is exclusive because of the superb acoustic properties of sapphire crystal.

In accordance with Chopard, the creation of the Full Strike required 15,000 hours of improvement and three patents have been filed, together with one for the single-piece sapphire block. Machining the gongs/glass alone required greater than three years of improvement! Outfitted with clear sapphire crystal gongs that produce a clearer, purer tone than steel, the sound (tuned to notes C and F) is akin to somebody tapping a wine glass with a knife.

In the identical vein, Chopard has additionally been engaged on buzzing noises produced by the governor, which might degrade the musicality of the sound produced by the gongs. Additionally, a new structure of the motion permits for the avoidance of silences between the hours being struck, the quarters being struck and the minutes being struck. A chime is usually punctuated by lengthy silences. Not right here. The construction of calibre L.U.C 08.01-L allows it to skip these silences mechanically. Its hours, quarters and minutes gear trains are superimposed and mutually drive one another. When one has accomplished its job, it mechanically triggers the subsequent, sustaining a continuing cadence.

There’s extra to the Chopard Full Strike than simply its crystal gongs. It’s additionally about power administration. The power for the placing mechanism is saved in a devoted barrel, and never generated by the actuation of a set off – similar to in a Grande Sonnerie watch. The crown serves to wind the motion in a single route, and its placing mechanism within the different. And thus, the minute repeater mechanism is actuated by a discreet pusher, and never by a big set off on the aspect of the case.

The Patek Philippe Fortissimo FF amplifier

The most recent improvement within the subject comes from Patek Philippe with the 5750 Superior Analysis Minute Repeater and its so-called Fortissimo “ff” amplifier module, offered in late 2021. The thought of Patek with this new member of the Superior Analysis household was to enhance the sound degree, richness and musicality of the minute repeater through the use of novel strategies however conventional supplies, or as defined by the model “to amplify the amount of the time strike in a purely mechanical method whereas preserving the superb acoustic high quality in addition to the smallest attainable dimensions.” And to try this, ranging from the present repeater calibre of the model, the watchmakers of Patek have created a brand new module that works like a mechanical loudspeaker.

Often, amplification of the sound does depend on a versatile diaphragm which just like the pores and skin of a drum is connected alongside its periphery. For its newest progressive mannequin, Patek Philippe has developed one thing unprecedented, an answer for which Patek Philippe registered three patents has an oscillating wafer made from artificial sapphire with a thickness of 0.2 mm. Due to its angular movement, this inflexible and freely movable wafer gives clearly higher sound propagation for the confined quantity of a wristwatch. Plus, this enables to retain the sapphire caseback and thus the chance to admire the motion.

To realize sound transmission from the gongs of the minute repeater to the sapphire-glass oscillating wafer, the engineers developed a system with a metal sound lever that’s connected in the midst of the oscillating wafer. The opposite finish of this sound lever that resembles a tuning fork contains a versatile attachment with a thickness of 0.08 mm. When the hammers strike the gongs, their oscillations are transmitted to the sound lever which in a primary section amplifies them and transmits them to the inflexible oscillating wafer the place they’re additional amplified. The angular movement of the oscillating wafer excites the air layers above and beneath the sapphire glass, producing a noticeably louder sound.

With the Patek Philippe Superior Analysis 5750 Minute Repeater, the model additionally labored on the propagation of the sound, along with amplifying it, by engaged on the case structure. Classically in a repeater watch, the sound of the hammer placing the gongs is propagated via the complete watch, on all sides of the case, on the again and thru the crystals. Thus, the selection of the fabric is essential, as it can have a direct impact on the standard and loudness of the sound. Gold and platinum are denser and thus soak up the sound greater than metal and even titanium.

Within the Patek Philippe 5750 Superior Analysis Minute Repeater with the fortissimo module, an insulation rim made from a high-tech composite materials acoustically uncouples the amplifier from the motion. The sound is first routed to the sound lever after which to the oscillating wafer and subsequently propagated via 4 openings at 12, 3, 6, and 9 o’clock in a titanium ring. The sound waves exit via a slender slot between the caseback and the caseband. Thus, the case materials has no extra affect on the sound of the watch.

Lastly, the Patek Philippe Superior Analysis workforce has labored on the loudness of the sound, but additionally on the standard, richness and musicality of the minute repeater. For example, the size of the strike has been elevated to ensure that the gongs to fade considerably longer. Some evolutions have been carried out on supplies too. Classically, hammers are made from metal however on this Superior Analysis 5750 Minute Repeater, they’re made from platinum – a patented answer that improves the standard of the strike.

For extra particulars about every of those watches, please go to audemarspiguet.com, chopard.com and patek.com.