SJX Watches
In-Depth: Understanding Resonance in Watches
Resonance watches are among the most elusive machines in modern watchmaking. Creations such as F.P. Journe’s Chronomètre à Résonance perform well at auctions, commanding high prices. While their rarity and appeal are undeniable, watches that purport to harness resonance tend to be viewed with a degree of skepticism. A measure of skepticism is understandable - the concept of sprung balances becoming almost magically coupled is anything but straightforward and requires a profound understanding of oscillators in general. This story seeks to shed some light on the concept of coupled oscillators by explaining the two models of coupling and explore the nuances of each system. Before exploring resonance, the reader is encouraged to review the basics of sprung oscillators and isochronism in order to become more familiar with the hairspring and balance wheel model. The F.P. Journe Chronomètre à Résonance Souscription No. 2 sold for more than CHF3 million in November 2025. A confusion of terms First, the term resonance itself requires definition. In classical physics (mechanics, electrical engineering, signal processing, etc.) resonance is a phenomenon where a system vibrates under the influence of an external driving force that matches the system’s eigenfrequency (natural frequency). This is to say that a system at rest, which includes mass and spring elements, can be excited into a state of resonance by an external force when particular conditions are met. An imp...
