Timepiece Chronicle

In-depth, passionate and entertaining articles that explore the stories behind great watches

It's just noise to me: Minute repeaters and sonnerie explained

It's just noise to me: Minute repeaters and sonnerie explained

The minute repeater and sonnerie complications are perhaps two of the most desirable complications that a timepiece can have. They are also a perfect analogy for mechanical watch collecting ; a deeply intimate yet outdated piece of technology that is utterly charming in every conceivable way. Rather than being made today because there is a need for them, these complications are made because watchmakers want to make them. Two years ago I visited the Swatch service center in Southampton, England, and the top watch repairman there said that whilst a tourbillon requires more technical skill to create and service, the minute repeater is the most fun to work on. No repeater is the same as each has a different tone and resonance making each the experience of servicing a watch with that complication a unique experience.

The most complicated watches ever made, the Patek Philippe Supercomplication & the Vacheron Constantin Ref. 57260 for example, all have minute repeaters and sonnerie complications yet it is easy to fail to understand what they actually do. Understanding how a minute repeater works  when isolated from other functions is easy but in relation to a grande sonnerie or petite sonnerie one can end up grasping at horological straws for answers. I will admit ignorance whilst reading certain Hodinkee articles, having nodded quietly to myself pretending to understand what was being described hoping that no-one nearby asked me to explain what I was reading. I would wager that some of you reading this have felt the same way as well.

A minute repeater, like a chronograph, is an actionable complication that can be activated at will by the user, typically through pushing a button or lever on the side of the case. Once the repeater is activated, a variety of levers and gears whir into motion, promptly "learn" the time from the movement and chime that time out accordingly through a series of small gongs. A sonnerie is a non-actionable complication, like a date wheel, which will activate without any input from the user. A petite sonnerie (French for Little Strike) will chime every quarter of the hour and will chime the hour at the hour. A grande sonnerie (Grand strike) will chime the hour in addition to every quarter and will also chime the hour at the hour as well. It is usually the case for minute repeater and sonnerie complications that the time is chimed out on two gongs, one low pitched for the hour, one high pitched for the minute and a quick high-low strike for quarters. One difference between the complications that plagued watchmakers for years is that a sonnerie typically requires its own energy source whereas a minute repeater can draw its energy from the main spring.

To fully understand the development of the sonnerie  you have to go right back to the beginning of watchmaking. There are examples of pocket watches using a strike mechanism to sound time dating back to the late 15th Century however these mechanisms were unreliable. The early "count wheel" or "lock plate" mechanism would remain popular with French and American clockmakers well into the 19th Century even though the chiming mechanism was prone to desynchronize from the hour and minute hand. An alternative method known as "Roman Striking", developed by 17th Century clockmaker Joseph Knibb, never truly caught on. Two differently pitched bells would strike the hour, one bell for Roman numeral "I" and another for "V" ("X" was counted as two "V"s).  This system had the benefit of never needing more than four strikes to tell the hour but was unable to strike at any other increments. It wasn't until 1676 that Rev. Edward Barlow invented the "rack and snail" method of striking time which is still in use today. The benefit of Barlow's new mechanism over previous attempts was that the chiming mechanism would always stay in constant  synchronization with the hands. 

The "Snail" part of the mechanism is a spiraled wheel which resembles the shell of a snail. Around the outside of the wheel, steps are cut into it with the number of steps varying on what that particular snail wheel is measuring; an hour snail would have twelve steps and  a quarter snail would only have four steps. Each snail wheel is directly connected to the relevant hand so it can never get out of sync and confuse the chiming mechanism. The hour snail takes twelve hours to rotate fully, the quarter snail one hour and the minute snail fourteen minutes. Why fourteen times rather than sixty? 

The rack is a flat curved piece of metal which has notches cut into either side and is suspended above the snail wheel ready to fall into place at the appropriate time. As with the steps in a snail wheel, the amount of notches on a rack will depend on what that rack is measuring and how many strikes of the gong it is looking to create. When the sonnerie activates, the rack drops into place with the amount of inner notches available being dictated by the position of the snail wheel.  The racks move to the end of their travel with their outer notches engaging pallets which in turn engage the striking mechanism to strike the correct amount of chimes. The racks then return to their original position ready to strike again. If kept fully wound, a full grande sonnerie will repeat this process 96 times a day and over 35,040 times a year. 

English watchmaker Thomas Mudge. Photo courtesy of Wikipedia.

English watchmaker Thomas Mudge. Photo courtesy of Wikipedia.

Whilst this might seem complicated, imagine trying to now invent a movement which can do all the above yet at the whim of the user at any possible moment? It wasn't until 1750 when Thomas Mudge invented the minute repeater and chose to use bells to strike the time. In addition to the hour and quarter snails, a third wheel to count the minute was required. This additional snail-wheel however only required fourteen steps rather than sixty as any amount of time of fifteen minute can be measured in partnership between the quarter and minute snails. In several textbooks I've seen reference to "feeler-spindles" which act as a mechanical memory for the minute repeater complication, able to "pick up" information on the present time and transmit the to the gathering pallets.  Legendary watchmaker Abraham L. Breguet would refine Mudge's system by replacing the bells with gongs as it reduced the thickness of the watchcase and obtained a clearer sound. Breguet would place the gongs towards the edge of movement and have a thin metal ring running around the circumference of the case, typically made of steel for it's superior resonant qualities. The weight of the gong and where it was hitting along this steel ring would vary the pitch and tone of the chime allowing for far greater auditory control than before.

If the minute repeater is activated at 9:37am, there will be 18 strikes : nine low strikes for the hour, two high-low strikes for the quarters and seven high note for the minutes.

Over the next two hundred years there were several advancements in minute repeaters with sounds becoming clearer and louder with more accurate yet it wasn't until 1992 that a real breakthrough happened. Philippe Dufour created the world's first wristwatch with both a minute repeater and  grande et petite sonnerie complications. The first series of the Grande Petite was limited to just four watches cased in yellow, rose and white gold and platinum, all with an enamel dial. In 1999 Dufour released two Grande Sonneries with a sapphire dial, one in white gold and another in rose. Whilst the movement is technically impressive I have never been a fan of clear or skeleton dials and this watch is unfortunately no exception. In 2005 Jaeger LeCoultre released the Master Minute Repeater Antoine LeCoultre which transmitted the sound directly through the sapphire crystal creating an unparalleled level of auditory quality.

Despite advancements in the technology of chiming mechanisms there still remained one major hurdle for watchmakers, the excessive amount of energy that a sonnerie would use. Francois-Paul Journe had been received requests from his clients to create a minute repeater grande et petite sonnerie however he refused to make one unless he could make the movement more durable, solve the power reserve problem and ensure that the watch was simple enough for an eight year old to use without damage. It took several years and ten new patents to make but in 2005 he unveiled the F.P. Journe Sonnerie Souveraine, the first minute-repeating wristwatch with grande et petite sonnerie to have one source of power. It was a combination of several new inventions which allowed Journe to only have one barrel. He created a mechanism which blocked off power to the sonnerie if the power reserve of the watch was below twenty four hours,  he made it impossible for the sonnerie to activate during time setting and for the time to be changed whilst the sonnerie was striking. In silent mode the watch could run for nearly five days and with all striking mechanisms activated for two days. Below is an amazing behind-the-scenes video that Hodinkee produced earlier this year which explains the process of making a watch and how the striking mechanisms works in greater detail. To this day the watch remains the most complicated piece the F.P. Journe make and instead of a serial number identifying the watch the owner's name is engraved on it instead making an already intimate watch seem all the more connected to you.

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