Suono nelle complicazioni

Sound in watchmaking is not a side effect: it is a complication unto itself, designed with the same care reserved for the escapement. Minute repeaters are the highest form of this discipline. When the lateral pusher is activated, a selection train of wheels reads the time, and a series of levers translates that reading into strikes: hours on the low notes, quarters on a double note, minutes on the high tones. The result depends on every link in the chain.

Gongs are the first critical link. Classical ones are made of hardened steel, hand-tuned file by file until the frequency is right. Cathedral gongs wrap around the movement for nearly two complete turns: the greater length produces a longer vibration, a slower fade, a fuller timbre. Patek Philippe in caliber 5750 mounted platinum hammers instead of steel: the higher density transfers more kinetic energy to the gong, improves the richness of the strike and extends the decay. Chopard in the L.U.C Full Strike went further, carving the gongs from a monolithic block of sapphire crystal tuned to C sharp and F: the sound approaches the tinkling of crystal glass, without the imperfections of welds. Audemars Piguet with the Supersonnerie mounted the gongs on a 0.6 mm sapphire crystal sound board, patenting a system that acts as an internal resonance chamber before the sound even reaches the case.

The case itself is the second link. The soundbox, that is the free air volume around the movement, amplifies or dampens everything. A poorly calculated case can nullify perfect gongs. The Hourstriker by Ulysse Nardin, developed with Devialet, uses a 0.3 mm DLC titanium membrane connected to the gong via a torsion bar: it vibrates like the diaphragm of a speaker, pushing air outward. An alternative solution, still on that model, channels the frequencies through eight perforations on the case back, reaching 85 dB at 100 mm distance. The super-compressor case of Jaeger-LeCoultre in the Memovox exploits the geometry of the double case to amplify the alarm's resonance.

The carillon adds a third hammer and a third note, multiplying the mechanical complexity. The parameters a watchmaker evaluates by ear are clarity, rhythm between the strikes, background noise of the rake regulator, tonal richness and volume. Often they are in tension with each other: increasing volume tends to muddy the clarity. There is no formula. There is only patient tuning, ear to the bench.

The tachymetric scale on the chronograph dial connects to the same physical principle: the difference in speed between light and sound allows you to calculate the distance from an event that generates both, such as lightning or an explosion.