In 2004, FP Journe made a fairly monumental shift to begin manufacturing all of their movements from 18k gold, following brass. In that year, Journe updated the Resonance with a new reference, the RN (Resonance Nouveau) series with a 1499.2 calibre. Shortly thereafter, that movement was updated to include a power reserve in the 1499.3 calibre. As a result, this second series RN is considered a transitional reference. It was in production for just two years and is today rarer than the its predecessor or successor on either side. Despite that, the market is only just waking up to that reality.
The effects of resonance in horology were first noted by mathematician and physicist Christiaan Huygens in pendulum clocks that would often synchronize. Antide Janvier and AL Breguet later applied this concept to two closely placed balances, later applied to pocket watches and flirted with by George Daniels. These early efforts intrigued a young FP Journe, who executed the concept masterfully in his 1990 prototype N°1 resonance. Two separate, free sprung balances with a regulator placed in between to limit vibrational transmission within a correct range, all condensed to a 38mm wrist-worn case. A new breed of timekeeping for the wrist.
Since that time, arguments and debates have drawn out ad nauseam just to what degree the effect of resonance regulates mechanical escapements on this scale. The effect is that of periodically applied force acting upon two systems in oscillation equally. The effect can be accurately modeled through Fourier transforms (which are a bitch) in modern physics (just so happens to be my degree), or loosely as a series of harmonic oscillators. The architecture is simple; two balanced wheels close to each other in a sealed environment will have a tendency to synchronize and, therefore, even out imbalances in each other’s rate. Think of it like all those times you’ve seen two like personalities marry, only to become carbon copies in old age. This is the broadest possible application of Newton’s Third Law on display.
Aside from the aformentioned rarity of this series, the rest is as expected. The 40mm platinum case with dual rope crowns shows little wear across its surface. The dial is perfect as one would expect, not fault to be found. It comes on its original alligator strap with a full set from a well-regarded retailer.
Find this Chronomètre à Résonance here from Timexchange listed as POA.