Hi Steyer, that is indeed a super interesting question....

Nov 19, 2022,18:30 PM

I will refer you to an article written by Jack Forster for Revolution Magazine in 2014 on the matter. In the article he is referring to George Daniels book "The Art Of Breguet" and how Breguet was studying experiments with vacuum.

This article was already referred to by our member cmmnsens elsewhere in this tread but it is easy to miss. Im taking the liberty of posting an extract of the article here but I urge everyone to read the full piece. Also Jack Forster wrot an article for Hodinkee on Resonance where he includes more details.

Link to Jack Forster article about Resonance for Revolution Magazine may 2014: revolutionwatch.com /

Link to Jack Forster article about Resonance for Hodinkee: April 2020: www.hodinkee.com 

Here we go:
"Over the years since the Chronomètre à Résonance watch appeared, there have been several objections raised by skeptics and I’ve been myself guilty of being fairly vocal in airing my own doubts. The two objections are that firstly, the rotational movement of a balance seems insufficient to induce a resonance effect and, as a corollary, the energy in a balance is too small to propagate through the plate to the other balance; it seemed unlikely that two balances could be mechanically coupled through a watch plate in the same way that two pendulums can be coupled through their suspension.
The second objection was that, given the construction of the Chronomètre à Résonance, in which the balances are set very close together, the two balances if they influenced each other at all did so by aerodynamic effects rather than mechanical resonance through the plate. Such an aerodynamic coupling would be affected, one presumes, by changes in barometric pressure and temperature and not produce a satisfactory mutual compensation of the two balances for any error in either.
This second objection led to the observation that a sure way to test the Chronomètre à Résonance would be to put it in a vacuum chamber and see if a resonance effect could be observed, and over the years, on various internet discussion forums someone would occasionally say they remembered hearing from someone who had heard from someone that someone had tried to put a Chronomètre à Résonance in a vacuum chamber and it hadn’t worked. Or it had. But nobody, it seemed, could ever remember exactly who it was who’d tried it.
A few weeks ago, in pursuit of information on something else, I happened to open a book I’ve looked in on countless occasions: The Art Of Breguet, by Dr. George Daniels, published by Sotheby’s. Like so many of the horological reference books in my library, I use it as a reference book –which is to say, I’ve never read it through entirely but merely gone a-hunting in it for information on specific subjects.
As luck would have it, this time the book happened to fall open onto pages 76 and 77. And, further, as luck would have it I happened to read this sentence:
“I thought that the air would have a very great influence on their facility to work together . . . I was very surprised to find that it influenced the mechanism far less than the effort accord each other by the impulsion of their mutual movements.”
I was thunderstruck, and read the rest of the section closely –and then, the related section on Breguet’s experiments with resonance pendulum clocks.
As it turns out –and I find it hard to believe that someone else hasn’t noticed this; surely someone has and I just missed it being mentioned on some discussion forum or other –the person who first tested a dual-train resonance watch with a double balance system in a vacuum was none other than Breguet. In the same (undated) document on his experiments with resonance, he notes, “The first of these double watches (no. 2788) was three months in the hands of M. M. Bouvard and Arago without the seconds hands having parted by the smallest part of a second; it was put twice in a vacuum and maintained in ‘absolute void’ for 24 hours, as well as worn, laid flat, and hanging from a chain without ceasing to keep to the second.” Breguet apparently fitted no. 2788 with a thin steel barrier between the balances to rule out the effects of turbulence on the balances as well, but as the text by Daniels notes, ” . . . as he was now satisfied with his conclusion he did not include it in no. 2794″ (his next resonance watch.)
So if it’s not air friction coupling the balances, what is it? Daniels remarks (p. 76) that “His experiments with clocks led him to conclude that the whole of the matter composing the frame was in continuous microscopic motion with the vibration of the pendulum. He realized that the same phenomena must occur in a balance wheel system where the motion would be transmitted to the plate of the watch by the couple of the balance and the spring at the limit of the arc of vibration.” Later Daniels also notes that, ” . . . excepting in some of his later tourbillon watches it is rare for Breguet to use a spiral spring without a regulator, but in this case it was essential if the effect of the vibration was to be fully transmitted to the cock.” This is apparently a key point —a conventional regulator, with its two pins, reduces the mechanical coupling of the balance spring to the cock and mainplate at the limits of its “breathing,” to such an extent that a resonance effect cannot be achieved.
F. P. Journe’s Chronomètre à Résonance is constructed along exactly these principles. The balances are free-sprung (with no regulator) and regulation is through the use of weights to vary the inertia of the balances. As with Breguet’s resonance pocket watches, the adjustable masses used for regulation are inside the rim of the balance (in the case of Journe’s watches, on the arms.) Breguet’s notes on pendulum clocks are detailed and he notes that the two oscillators have to be closely regulated to each other for a resonance effect to occur although this is dependent on the stiffness of the common mount. Breguet apparently experimented with different attachment points for the balance cocks in his resonance watches, as they vary from one watch to the other.
The technical notes on the F.P. Journe website are as is always the case for Mr. Journe extremely technically detailed (I wish other brands offered the same comprehensive data) and there one can read that the frequency of the balances is 21,600 vph (3 hertz.) I don’t know how long Mr. Journe experimented with these systems or how many variations were tried but I suspect there is probably a sweet spot of some sort involving balance inertia, frequency, and construction of the cocks and plate that gives optimum results; Mr. Journe did mention, in an interview from 2003, that the balances needed to be regulated to run within 5 sec/day for a resonance effect to occur (Breguet’s pendulum clocks, depending on the stiffness of the suspension, might be able to be as far as 20 sec/day apart in rate but still begin to resonate) and in the same interview he also alludes to some of his early experiments with a pocket watch prototype.
To achieve a true resonance effect as Journe has done in a wristwatch this small (38mm and 40mm, and only 9mm thick) is quite remarkable to say the least, and the problem of adjusting the two balances so that they both keep time accurately and run to a variation in rate of no more than 5 sec/day and do so with no more than a 5 sec/day rate variation between the two of them is . . . well, let’s just say I wouldn’t want to do it.
The whole saga is instructive on a number of points but perhaps mostly on these two: the value of reading one’s books, and of keeping an open mind. I am as sure as I have ever been of anything that Mr. Journe knew of Breguet’s notes perfectly well but every instance I know of of persons asking him how the Chronomètre à Résonance actually works has been met with, essentially, a rather Gallic shrug and occasionally a remark along the lines of “well, it works.” Given his known tendency to not suffer fools gladly I can only assume what he meant to convey was “if you can’t be bothered to do a little research I’m not bloody going to tell you.” In any case, though it’s been 14 years now since the Chronomètre à Résonance first saw the light of day and the arguments over whether or not it could work (and how it could work) began, it’s as enormously intellectually satisfying to understand the principles behind the watch –finally –as it is humbling to realize the answers to my questions were hiding in plain sight in one of the most often consulted books in my library. So, Mr. Journe, mea culpa, mea maxima culpa, for all those years of unwarranted criticism. Er, sorry about that."

Extract from Revolution Magazine May, 2014. Jack Forster 

To your question about the ability to regulate the right balance wheel. I am not totally sure and I will ask Francois-Paul but I do know the following about it. If the balance wheels are in too close proximity they can create a turbulence or air cushin that disturbs the Resonance. I also learned from the watchmaker building the resonance that he doesnt spend a great deal of time adjusting this distance. The real work goes in to a) regulating the both sides in 6 positions within the 5 sec delta. b) making sure that the recieved components are set up so the behave indentically. e.g. the spirals must be exactly similar. I will try to ask more when I have the chance.

About your last question i have never heard such a claim. I suspect you may confuse it with the power reserve of 28 hours. the RQ only has one barrel. after the 28 hours the two Remontoir d´Egalite disengage. the match will run for some more hours, but of course not to the same spec.

I hope this sheds some light on your questions.

More posts: ChronometreGeorge DanielsResonance

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Comments: view entire thread


Resonance described through control theory

 By: andrea~ : November 13th, 2022-21:43
Have you ever heard of a feedback loop? If you haven't, I can best describe it as a way in which a system can actively detect its output through a sensor and make changes to its variables in order to achieve and maintain a certain desired state automatica...  

Gorgeous movement,

 By: InHavenPro : November 13th, 2022-23:55
inspiring science. Love it, Filip

Thank you!

 By: andrea~ : November 14th, 2022-07:19

The two oscillators are mechanically uncoupled, right?

 By: mezentius : November 14th, 2022-01:13
How do they compensate and stabilize each other? Through vibrations on the mainplate? Or maybe movements in the air?


 By: andrea~ : November 14th, 2022-07:19
The mechanical coupling happens through vibrations, and the mainplate is the means to achieve it, since both oscillators are mounted on top of it.

That's very cool

 By: mezentius : November 14th, 2022-07:47
I wonder if they're using any special materials on the mainplate to enhance the coupling... I'd expect something more rigid would be better? No doubt shape would matter as well... I guess I'm wondering how much this effect has been optimized with modern m... 

You are right, the harder the material is, the better the coupling will be

 By: andrea~ : November 14th, 2022-08:04
No new materials are being used, the mainplate is either brass (found in early versions) or rose gold, but the results are good regardless.

 By: mezentius : November 14th, 2022-08:11
Haha, looks like I would have to get a brass resonance to satisfy my optimization tendencies then! That's very bad news for my wallet though, I guess I'll have to stick with admiring my little CS for now...

Hahaha I know, I love the resonance but the price is a little steep 🤣

 By: andrea~ : November 14th, 2022-08:51
A CS is a beautiful watch regardless

I think it is a phenomena called resonance

 By: Cookies : November 14th, 2022-08:20
Very interesting to read about it. I watched a youtube video on it and it is mindblowing how this mysterious phenomena happens.

It's exactly that

 By: andrea~ : November 14th, 2022-08:52
The resonance effect makes the balances couple by the mechanical waves that propagate through the mainplate

How does all this hold up with a moving wrist?

 By: BigFatPauli : November 14th, 2022-13:32
We've all seen the metronomes sync up on a table but has anyone tried it, say, in a moving car on a road? I think we can all easily envision their inability to stay synced with each bump or turn. Clock makers used the system in clocks, which are stationar... 

A hard knock can make it fall out of sync, but the balances will reestablish the the Resonance

 By: ChristianDK : November 14th, 2022-15:20
If you watch this lecture from HSNY you will see a video of the balances being disturbed and the go back in to resonance. How does it hold up on the wrist? In practical terms I can wear mine on the wrist for days without the seconds hands falling out of ... 

There's a difference

 By: andrea~ : November 14th, 2022-20:16
This analogy doesn't necessarily work since metronomes in a car would have to be fixed to the car and even then there's a huge difference with resonance in a wrist watch. The effect of your wrist moving doesn't impact the vibrations of the oscillators in ... 

There's a difference

 By: andrea~ : November 14th, 2022-20:16
This analogy doesn't necessarily work since metronomes in a car would have to be fixed to the car and even then there's a huge difference with resonance in a wrist watch. The effect of your wrist moving doesn't impact the vibrations of the oscillators in ... 

You believe whatever you like. I know many are very passionate about the brand.

 By: BigFatPauli : November 14th, 2022-21:09
And after all, this is a purely passion based hobby: no one needs a mechanical watch.

I'm not a huge Journe fan

 By: andrea~ : November 14th, 2022-21:15
I'm personally not a mechanical engineer so my knowledge of the field is restricted, from what I can understand it seems like it does work, but again, I'm not qualified to talk about that aspect. Being skeptic can be good of course, proof is important, I ... 

Well, one thing to consider is how it is implemented by other brands...

 By: BigFatPauli : November 14th, 2022-22:02
Consider Dufour, for example, where he used a differential system. That system as also adopted by MB&F. Armin Strom uses a "Resonance Clutch Spring". In all cases, the balances are physically connected which is probably more reliable than counting on ... 

There's a few differences

 By: andrea~ : November 14th, 2022-22:10
In the case of the Dufour, the watch isn't about the use of resonance, that's why it's not the same as the Journe. The Resonance Clutch Spring is a nice feature, but not essential for resonance to happen. Resonance was actually discovered when Christiaan ... 

"Resonance was actually discovered when Christiaan Huygens ...

 By: BigFatPauli : November 14th, 2022-23:26
...observed how the two pendulum clocks he had on the wall of his room synchronized after oscillating for a while. Just like the wall allowed for that coupling, the mainplate allows for the coupling of the balances in the Chronometre A Resonance. " Sure. ... 

Mine works.

 By: TheMadDruid : November 15th, 2022-00:05
Have you ever played with one? Worn one? I wouldn’t be so condescending about something I hadn’t experienced myself.

I'm sorry if you feel I was condescending: that was never my intention.

 By: BigFatPauli : November 15th, 2022-00:26
All I am asking for is a simple proof of concept. Can you provide one?

I think without some serious calculus

 By: mezentius : November 15th, 2022-03:35
You would not be able to provide a proof of concept. That is, I don't believe that a proof of concept would be "simple", and I don't believe that a simple explanation would be "proof". That being said, I'm not a mechanical engineer but I would believe tha... 

That's so true!

 By: andrea~ : November 15th, 2022-07:27
It's not an easy thing to prove, this is not my field, but everything makes sense to me. I'd gladly lend you a resonance if I had it 😅

It actually should be an easy thing to prove....

 By: BigFatPauli : November 15th, 2022-12:07
The whole concept is based on metronomes on a table syncing, or clocks on a wall. That's the proof of concept. Simple. The fly in the ointment is that the table or wall are stationary and not having external, irregular forces acted on them (like a moving ... 

The balances are fixed in relative position to each other

 By: mezentius : November 15th, 2022-17:41
So translational movements such as "slightly nudging the watch" as you say will affect both equally. The movements which will act significantly differently on the wheels involve rotations about a center which is close to one balance wheel. The distance fr... 

You have already been given plenty of proof in this thread. But you chose to ignore the arguments, video clips ect and stick to your home made theories.

 By: ChristianDK : November 15th, 2022-17:49
You have been here before Pauli. I am sure no matter what arguments you are presented with, your disregard for this watch and FP Journe generally, will remain. When You own the watch, you know when it works or when it doesn’t. Just I’ve said all along. Fu... 

Again, I am not asking for a scientific paper. I am just asking for a simple proof of concept.

 By: BigFatPauli : November 15th, 2022-23:40
I understand that people get defensive of this, but I wish that wasn't the case: I am just trying to understand how it is supposed to work and I am not attacking anyone, or their choice or watch. You say I have been shown proof here... I have seen people ... 

I don't have a way do that while wearing the watch and moving around.

 By: BigFatPauli : November 16th, 2022-11:39
But, yes, I would I love to see a video like that. More so, I would like to see someone put one a machine able to measure the two seperate beat rates and amplitudes, be able to move that around, and see how long it takes for the balances to naturally re-s... 

Paul raises a good point though.

 By: Cozmopak : November 16th, 2022-22:37
I believe that the resonance system works while at rest, but I would like to see proof that it persists with the wrist in motion. That's important. Or if it doesn't persist, how long does it take for it to come back in sync?

I imagine it will decrease variance

 By: mezentius : November 15th, 2022-09:39
From factors caused by differences between individual balance wheels/springs such as manufacturing and setting imperfections, but not those caused by factors affecting both wheels equally such as position on the wrist... Unless perhaps Journe designs a re... 

I get it in concept but shouldn't all those factors be accounted for when the watch is made and regulated?

 By: Fastwong : November 15th, 2022-14:24
In particular, the dual balance systems are really hard to regulate as seen by the propensity of the Resonance watches needing to go back to service for tuning... And also Max Busser talked about how much of a pita it is because you can just stick it on a... 

To be honest,

 By: mezentius : November 16th, 2022-05:49
I never understood why one had to be slow and one had to be fast. I've always thought the point of resonance to cancel out variances within the operation of each balance - to improve precision, not accuracy. Intuitively, that should occur no matter if the... 

Just to clarify. you dont have a slow and a fast balance. They are regulated to the same frequency. Ideally +/- 0 sec on all 6 positions...

 By: ChristianDK : November 16th, 2022-15:29
The mentioning of the slow and fast balance refers to the situation where the watch receives a knock. this disturbance will cause the balance wheel to either accelerate or slow down briefly. Since the two balance wheels run in opposite direction they will... 

I understand they need to be regulated to the same frequency in order to achieve resonance but I think it's safe to assume that at the smallest level they are not identical because then it would all be pointless.

 By: Fastwong : November 16th, 2022-15:47
My point being, could one of the balances be overall more accurate than the other in which case having two balances is detrimental to time keeping? Given that a single balance is easier to regulate, practically a single balance might be the more accurate ... 

On the Micro level you are right, of course

 By: ChristianDK : November 16th, 2022-18:36
They can not be regulated to exactl same. Just close enough and then they will begin to synchronize and resonate. This does help timekeeping in that er evens out error and creates a more stable running. To your other question about what is more accurate, ... 

Yes, he is quite clear on this

 By: ChristianDK : November 17th, 2022-07:08
He considers a Tourbillon, first and foremost a thing of beauty and fascinating. He has said that installing a Tourbillon is like deliberately breaking a leg to put a casket on it to fix a problem. It solves a problem but it also creates more problems tha... 

Thanks for explaining!

 By: mezentius : November 16th, 2022-19:16
But this phenomenon makes me more doubtful. I would imagine the vibrational forces coupling the two balances together at the moment of impact would be orders of magnitude less than external shocks acting on the balances as they move, and so only would aff... 

They are difficult to regulate because both sides need to be regulated to almost perfection in all 6 positions. That is hard in any watch.

 By: ChristianDK : November 16th, 2022-15:19
From what I have been explained by a watchmaker a watch can be well regulated in 5 positions and the watchmaker can "hide" the irregularities in the 6th position. The Resonance is unforgiving in that way. you need regulating in 6 positions x 2 to be withi... 

The proof can be seen in the wearing of the watch.

 By: TheMadDruid : November 15th, 2022-11:32
It’s that elemental; and that difficult. Assuming you aren’t an owner try going to a Boutique and playing with one.

what a nice post Andrea

 By: ChristianDK : November 14th, 2022-15:49
I really appreciate it. (even if formulas are not my strong side ;-)) I dont know if you ever watched this lecture at HSNY. I hope you will find it interesting. The Resonance is a very stimulating and fascinating watch in so many levels. Your last words i... 

I did

 By: andrea~ : November 14th, 2022-17:12
It was really insightful and helped me develop the mathematical model for this simulation

It's a pleasure!

 By: andrea~ : November 14th, 2022-20:17
I am an engineer, I studied control systems in the past but now my focus is on materials science


 By: massi. : November 14th, 2022-20:53

Grazie! 😊

 By: andrea~ : November 14th, 2022-20:55

Excellent, Grazie Andreas.

 By: ChristianDK : November 14th, 2022-23:03
Its a pleasure with such well informed argumentation. It reminds of the day I sat for some time with the watchmaker who assembles the Resonance and bombarded him with all kinds of questions. I asked him; "how can you be sure its not just two well regulate... 

It must have been incredible to see!

 By: andrea~ : November 14th, 2022-23:18
The resonance and the optimum are both fantastic pieces of horology and fascinating in how they approach chronometry

Wow, that sounds like quite a moment!

 By: Spangles - Dr. Tabby : November 15th, 2022-18:08

Yes, my friend. I will never forget.

 By: ChristianDK : November 15th, 2022-18:37

Thank you, it's a pleasure!

 By: andrea~ : November 14th, 2022-20:59
The great thing about this is that even within science, watches have many facets that can be explored, from mechanics to materials and everything inbetween, it's an endless pit of interesting discoveries


 By: massi. : November 14th, 2022-21:06
I remember as a child I was amazed at how such a small thing, to look at with the loupe, could produce such a loud tick-tock! Unfortunately, many have fallen for knowledge! 😢

A price worth paying ;)

 By: andrea~ : November 14th, 2022-21:17
(actually it probably depends on what you break 😅)

Ha! I had forgotten all about this article. Thank you, A!

 By: ChristianDK : November 17th, 2022-07:16
It encapsulates perfectly the delta between the vivid imaginations of members of watch forums versus real watches and real watchmakers. Kudos to Jack Forster for writing this. A former moderator here BTW.


 By: cmmnsens : November 17th, 2022-17:09

Through the mainplate, really ?

 By: Steyr : November 19th, 2022-08:06
Well, I have no doubts that both balance wheels are synched. I've seen it, and I am totally OK with that conclusion. But "How ?" still bothers me I don't believe this can happen through the mainplate. The energy would have to follow quite a path to make i... 

Hi Steyer, that is indeed a super interesting question....

 By: ChristianDK : November 19th, 2022-18:30
I will refer you to an article written by Jack Forster for Revolution Magazine in 2014 on the matter. In the article he is referring to George Daniels book "The Art Of Breguet" and how Breguet was studying experiments with vacuum. This article was already...