Ulysse Nardin Blast Hourstriker

Unveiled during the Watches and Wonders 2021 event, the Ulysse Nardin Blast Hourstriker is an innovative new striking watch.

In 2019, the Swiss Manufacture collaborated with French audio technology company Devialet and launched in the Classico Hourstriker Phantom. This year, with the Blast Hourstriker watch, the luxury Swiss brand has opted for more futuristic ways to reinterpret traditional watchmaking crafts.

Ulysse Nardin Blast Hourstriker

In general, to generate the sound needed to mark the passing hours, the hammer strikes a wire gong wrapped around the movement to which it is attached. The acoustic wave spreads into the middle of the mechanism and is partly absorbed by it. In these conditions, the sound heard lacks power and its harmonics are partially muffled by the material of the timepiece.

Ulysse Nardin Blast Hourstriker watch

For the Blast Hourstriker, Ulysse Nardin had to find the solutions for two challenges. The first one was to make the chiming mechanism visible on the dial side. The second challenge was to improve the quality/power output ratio.

To achieve these goals, Ulysse Nardin developed the UN-621 caliber. For ensuring optimal precision of Ulysse Nardin’s first in-house automatic striking manufacture movement, it is powered by a flying tourbillon; one that is equipped with a variable-inertia balance wheel, a silicon hairspring, anchor and escape wheel.

Ulysse Nardin Blast Hourstriker

The most complex phase of the Blast Hourstriker’s development involved redesigning the entire kinematics of this 330-component striking caliber to allow this highly sophisticated mechanism, which is usually hidden from view, to be seen dial side.

When the striker is on, the mechanical ballet that makes the watch’s sound is visible on the hour and half hour, but even its occasional activation is just as beautiful.

By pressing the button located at 10 o’clock, the mechanism, driven by a specially dedicated barrel, is triggered. The hour rack and the inertia regulator start to turn; the hammers, visible in an opening made at 12 o’clock, hit the gong whose shape has been subtly worked to bypass the cage of the flying tourbillon.

Ulysse Nardin Blast Hourstriker watch 2021

Finally, to ensure that the Blast Hourstriker’s striking mechanism acoustic performance perfectly audible, this movement incorporates a titanium membrane developed in collaboration with Devialet, the French audio technology company with whom Ulysse Nardin worked on its torsion lever used in 2019’s Classico Hourstriker Phantom. Interestingly, one of whose co-founders of Devialet is a direct descendant of the Ulysse Nardin family.

Ulysse Nardin Blast Hourstriker watch with rose gold case

As in the Classico Hourstriker Phantom, the torsion lever connects the heel of the gong to the fine membrane. In this construction, it is pressed against a grid to prevent it deforming in the event of extreme external pressure. This diaphragm is 3/10th of a millimetrer thick and treated with black DLC, which offers a large deformation area, which, when under load, moves a large volume of air, which improves the audibility of the sound produced.

Ulysse Nardin Blast Hourstriker

The Blast line’s signature double X cut into the rose gold case back, also ensures the security of this sensitive Devialet membrane, which, once in action, basically acts like a hi-fi speaker– releasing and amplifying the gong’s sound.

Ulysse Nardin Blast Hourstriker

To truly allow the sound of the Blast Hourstriker to resonate, the distinctive 45mm Blast case was given a black DLC titanium middle, capped with 5N18-kt rose gold, for improved acoustics.

Ulysse Nardin Blast Hourstriker

To silence this imposing timepiece with the button located at 8 o’clock on the middle must be pressed and then the ‘ON’ or ‘OFF’ position at the tip of the function selector hand located at 8 o’clock checked.

Ulysse Nardin Blast Hourstriker

The three straps that come with the Blast Hourstriker allow its different personalities to be explored. The black high-tech, waterproof velvet option emphasizes its aerodynamism, while the alligator brings its more sophisticated side to the fore. In addition, a rubber strap is also available for this model.

Technical details

Model: Blast Hourstriker

6215-400/02 (Alligator)
6215-400-3B/02 (Velvet)
6215-400-3A/02 (Rubber)

UN-621 Manufacture Caliber
Automatic tourbillon
Automatic Flying Tourbillon for the movement /Manual-winding for the chiming
Flying tourbillon, hours, minutes
Openwork movement on the dial side
Hour striker (hours and a half hours / hours on demand)
Devialet sound amplification system
330 components
23 jewels
Frequency: 4 Hz / 28,800 V/H
Power reserve: 60 hours

Rose gold 5N
Black DLC titanium
Glass box: Sapphire glass
Diameter: 45 mm
Case-back: Sapphire crystal
Water resistance: 30 m

Velvet, rubber, alligator

99’000 CHF / 91’100 EUR / 104’400 USD