A simple yet unusual chiming complication, the hourstriker has been a fixture in the Ulysse Nardin line-up for almost three decades, starting with the San Marco Jacquemart developed by Christophe Claret. The hour striker complication has been paired with various automatons over the years, including tigers, horses, oil pumpjacks, and a copulating couple.

Now Ulysse Nardin has stripped away the automaton, streamlined the design, and reworked the acoustics – with help from French speaker specialist Devialet – resulting in the Hourstriker Phantom. It’s the brand’s sleekest and most contemporary hour striker to date, and according to Ulysse Nardin, the loudest chiming wristwatch in the world.

High-end audio help

Founded in 2007 by a trio of Frenchmen, who named the company after 18th century French engineer Guillaume Vialet, Devialet is most famous for its white, egg-shaped Phantom Premier speaker that is compact, powerful and fairly expensive. Most notably, one of its founders, designers Emmanuel Nardin, is a member of the Nardin family that once owned Ulysse Nardin.

The Devialet Gold Phantom Opéra de Paris speaker

Devialet’s contribution to the Hourstriker Phantom was to boost its sound, accomplished in two ways. The first element being the attachment of the gongs to the movement. In an ordinary striking watch, the gongs are fixed with screws.

On the other hand, the Hourstriker Phantom has its gongs secured by “torsion arms”, presumably small springs. According to Ulysse Nardin, the torsion arms “change the direction of the action forces induced by the [gong’s] vibrations”, transmitting the sound to the outside of the watch.

Most of the sound is transmitted to a thin metal membrane fixed to the rear of the watch, essentially a second case back that acts as a sound board, a feature also found on the Audemars Piguet Supersonnerie repeater. The membrane itself has eight holes on its edge that allow the sound to escape the case.

The result is a chime that measures 85 decibels at 10cm, the highest in watchmaking according to Ulysse Nardin.

Chiming on the hours

When turned on, via the button at two o’clock, the hour striker chimes every 30 minutes, sounding the hours at the top of the hour and half past. In silent mode the watch stay quiet and tells the time conventionally. A tiny aperture at three o’clock indicates if the watch is on strike or silent mode.

The button at four o’clock sounds the striking mechanism on command, and the movement sounds the hours of the current hour; at 10:55, the watch will chime 10 times.

The Hourstriker Phantom powered by the automatic UN-610, which is the tried and tested ETA 2892 movement fitted with the hour striking module of Ulysse Nardin, explaining in part the relatively affordable price, as such things go. And maximise the sound, the case is lightweight titanium – materials that are less dense transmit sound better – although still large at 43mm in diameter.

The dial is open worked in the pattern of a Chladni figure, the pattern reproducing the shape of sound waves, which was discovered by German scientist Ernst Chladni.

Key facts and price

Hourstriker Phantom
Ref. 6103-132

Diameter: 43mm
Material: Titanium
Water resistance: 30m

Movement: UN-610 (ETA 2892 base)
Functions: Hours, minutes seconds, and chimes on the hours and half hours
Frequency: 28,800bph (4Hz)
Winding: Automatic
Power reserve: 42 hours

Strap: Alligator with buckle

Availability: Limited edition of 85
Price: 72,500 Swiss francs

For more, visit Ulysse-nardin.com.