Very confusing Timegrapher results

[VWatchie]

Can you spot the difference between the first and the second picture, and no, I do not mean the significant improvement in amplitude?

As it turns out, the only difference between the first and the second picture is that in the first picture the movement is mounted directly on the microphone stand, whereas in the second picture the movement holder is mounted on the microphone stand.

Again, the amplitude goes from bad to (sort of) acceptable when the movement holder is placed on the microphone stand. Coincidence? No, I tried it on and off the movement holder several times, and very consistently the amplitude increases when the movement is in the movement holder.

I can’t make any sense out of this, and I don’t know what the true amplitude would be. I can only guess and that is of course quite useless. Anyone having had the same experience or care to consider what the cause might be?

The movement is a just recently (and meticulously) serviced and adjusted Omega cal. 268, so I’d like to think the 300 degrees is closer to the truth, but I just can’t get it verified. Very frustrating!
 

[Endeavor]

As JohnR725 always says with timegraphers; rubbish in is rubbish out. The microphone receives a signal, passes it on to the processor and it's up to the software to make any sense out of it. It may well be that a movement, clamped in a movement holder and subsequently the combination is clamped in the microphone creates additional vibration or resonance (?) If that would be the case, the software may or may not correctly interpret the received data.

Which one is correct? My two cents; as per design, the movement directly in the microphone.

Do I know for sure: no I don't

 

Edited March 23, 2021 by Endeavor

[nickelsilver]

I agree the movement on the mic directly is probably the right one. This is probably one of the significant differences between these machines and "real ones" at 15x the price, the real ones seem to have a bit more sophisticated circuits that filter things better. I'm sure John will chime in, and he has experience with both- I just have experience with Witschi and then numerous old paper tape machines, haha. I did have the add on meter for those to see amplitude though.

[VWatchie]

5 minutes ago, Endeavor said:

Which one is correct? My two cents; as per design, the movement directly in the microphone.

I guess it makes sense but then again, this movement has been very carefully serviced. Everything is spotless, no hiccups in the train, pivots burnished where required, end-shake meticulously adjusted, the HS bouncing evenly between the index pins, and so on. Hmm...

[VWatchie]

5 minutes ago, nickelsilver said:

I'm sure John will chime in

I'm keeping my fingers crossed he will!

[Endeavor]

New main-spring?

I wish I could come up with an answer to make your day ......

How about filming the balance wheel with your iPhone in slow motion? With a video editor you can slow the video down even further. With a bit of luck, keeping an eye on one of the balance wheel spikes, you can spot the difference between 240 and 300 degrees?

[VWatchie]

53 minutes ago, Endeavor said:

How about filming the balance wheel with your iPhone in slow motion?

That sounds like a brilliant idea. I'll give it a try as soon as I can (hopefully within a couple of days) and will report back.

And yes, a new (Generale Ressorts) mainspring was installed.

Edited March 23, 2021 by VWatchie

[praezis]

Answer is quite simple. The noise is too quiet with mov holder (for this TM).

Tick noise consists of mainly 3 pulses, the first being by far the lowest (most times). If the TM misses the first, it takes the 2nd as start of escapement time, base of ampl measurement -> detected esc time too short -> amplitude value too high!

Didn´t I explain that just recently?

Frank

[spectre6000]

What does it do if it's missing a beat entirely though? In that case, it shouldn't have enough data to calculate all the parameters it's outputting. They're based on timing relative to one another, not relative amplitudes ("distance A-C" from the above graphic).

What is the difference between the movement on the mic and the movement in the case on the mic? If praezis is correct, it should be similar, or at least a step along the same trajectory.

If you want to get really nerdy, what is the mass of the movement holder vs. the mass of the case (relative is all that's necessary)? I would expect a similar result along a linear curve vis a vis mass delta. F=MA, where the more massive of the case/holder requires more force to accelerate (pass sound through). There's technically more at play, but the basic mathematical relationship should present itself in the results. We would know the relative masses, and the relative amplitudes (based on whether or not or with what degree of reliability the timegrapher catches the signal). Force should be based entirely on state of wind, and thus essentially constant. If the relationship holds, praezis's answer will be all but proven.

[Endeavor]

@praezis; I know we digress from the topic and perhaps that's how a timegrapher works. You may be 100% correct, but it doesn't make a lot of sense to me. It would make far more sense to me if the TG would measure the time in between the 3 pulses and the next set of 3 pulses. The way you explain the workings (and therefor VWatchies problem), the TG would measure the speed (=time) with which the impulse jewel performs the unlock till the final lock over the duration of the lifting angle. This would mean that the higher the amplitude, the greater the speed of the impulse jewel. All well, but what about the beat error?

If the time was measured between the last pulse, the lock, till the next first pulse, the unlock, that IMHO would also tell something about the amplitude and gives an indication of the beat error.

 

Edited March 23, 2021 by Endeavor

[WellAdjusted]

I'd agree that it would be best to visually confirm the amplitude, either with a slow-mo video or with an easily removable mark (like a UV ink dot on the balance wheel arm).

For what it's worth, out of curiosity, I just found identical readings with an old Rockford pocket watch mounted directly vs mounted in a movement holder.

[JohnR725]

There are several features missing on the Chinese machines that would be really nice to have. Like audio interesting when you listen to the watch ticking if there's other noises like hairspring is bumping into things. Another useful feature found on expensive witschi timing machines is our oscilloscope mode. Any time I have anything that looks weird I go to the oscilloscope mode. Then you can look at the waveform it never looks perfect like the one above. Then the example above is not technically correct there actually five sounds two of them overlap with two of the others. Unless of course you're having problems and then you start seeing those also. So with the witschi in our oscilloscope mode it also puts a line where it perceives locking is occurring. As stated above the amplitude is measured from the roller jewel hitting the fork and locking or basically unlocking to locking. The initial roller jewel hitting is super quiet sometimes it's not quite contributed correctly. Or locking that's really allowed that should be super simple but a lot of times which he gets confused. I'll see the amplitude goes 300 to something lower as it keeps jumping around where it thinks locking occurs. Basically of the timing machine cannot get a good clean signal you're not going to get the results you desire.

I see somebody beat me to the answer again up above you can use the video to help for this. There's a procedure for finding lift angle where you mark the balance wheel you adjusted 180° to figure out what you lift angle is. But as you already know what the lift angle is you can also use this to verify that the machine is correctly indicating 180° visually at 180°.

A suggestion in your first picture the crown is sticking off in some random direction I find it's more useful if you would stick it out the end as it makes it easier to keep track of which position you're in. Once you've done that why don't you rotate the microphone to crown down and try it with the microphone and with the movement holder and see what happens.

https://youtu.be/-Xgcck692js

Then these phenomenons you're seeing are not always unique to things like this for instance if the watches in a case it doesn't always transmit the sound perfectly through the case. I've seen this several times with Seiko is at work or heavy Rolex cases. The Seiko is I think because the relatively quiet and a using a plastic movement ring. The basically on the machine they look like well crap. Take the movement out to you get a beautiful line and its nice at least for Seiko. Sometimes the timing machine has an issue they're not perfect this is where the additional features of audio to listen to things is helpful the oscilloscope is nice to see if you can even see a decent signal. When you start seeing signals where you start seeing for parts of the signal you know you're having a problem but the timing machine doesn't have the brains to interpret on oscilloscope and it will just attempt to give you numbers and they may not always be happy number is because they're not looking at the correct part of the waveform because it can't pick it up correctly.

[Klassiker]

Slo-mo video as already suggested, to determine the true amplitude, and try adjusting the gain on your machine.

[JohnR725]

I was thinking about this discussion when I was at work today. If I knew ahead of time I would've taken a USB drive because I can do screen captures it look really nice verses a photograph but even in the photograph I think I'll get my point across.

You'll notice the waveform doesn't match the ideal perfect shown farther up. Also the timing machine puts a dashed line where it thinks locking is supposed to be. If you saw the full screen you'll see that there is two waveforms on top And two on the bottom and the only place where it will put the dashed line is on the first two of each line. So where I have the picture of both of them you'll notice once again the image waveform is not perfect like we always see it and the dashed lines are not in the same place.

Then when I was in our oscilloscope mode I was also looking at the amplitude. It kept changing just because the timing machine was being confused. The numbers were alternating between 245 and 277.

 

[praezis]

@Endeavor

Your description of amplitude measurement was correct, that's how it is done in TMs. Velocity within a fixed (lift-)angle.

- rate is tested as time between different noises and averaged

- beat error the same (and has nothing to do with amplitude)

- amplitude is tested as time between pulses in the same noise.

Frank

[Endeavor]

10 minutes ago, praezis said:

- beat error the same (and has nothing to do with amplitude)

Thanks for you elaboration !

Probably not measure by the TM, but if an escapement was servery out of beat, wouldn't the amplitude to one side not be different than to the other side? To my mind with a watch in beat, the impulse jewel sits in rest on the center line which runs between the banking-pins (sides). With "out of beat" the impulse jewel does not and therefore to one side of the rotation the hairspring is already tensioned when hit by the fork, whereas in the other direction the hairspring is still "un-coiling". This, to my mind, should have an influence on the directional amplitude. Perhaps not the "overall" amplitude measured by the TM, but resulting in an amplitude difference between either directions. This would make the amplitude not completely independent of the beat error.

Am I talking sense or non-sense ?

[praezis]

@Endeavor

no nonsense at all!
Technically a heavy beat error may influence the amplitude, but TM test of both is independent.

Amplitude display is the average of right and left swing, with B.E. one is wider, the other equally smaller.

Frank

[Jon]

21 hours ago, VWatchie said:

Can you spot the difference between the first and the second picture, and no, I do not mean the significant improvement in amplitude?

As it turns out, the only difference between the first and the second picture is that in the first picture the movement is mounted directly on the microphone stand, whereas in the second picture the movement holder is mounted on the microphone stand.

Again, the amplitude goes from bad to (sort of) acceptable when the movement holder is placed on the microphone stand. Coincidence? No, I tried it on and off the movement holder several times, and very consistently the amplitude increases when the movement is in the movement holder.

I can’t make any sense out of this, and I don’t know what the true amplitude would be. I can only guess and that is of course quite useless. Anyone having had the same experience or care to consider what the cause might be?

The movement is a just recently (and meticulously) serviced and adjusted Omega cal. 268, so I’d like to think the 300 degrees is closer to the truth, but I just can’t get it verified. Very frustrating!
 

Are these the only two ways in which you clamped the movement?

Everyone seems to have headed off in the direction of the timegrapher pick-up/algorithm problems in reading the signal etc. which it could possibly be. I've had different readings dependent on how my movement is fixed in the holder and it's orientation to the metal part, which is the mic. I find having the escapement as close to the mic (metal part) is always going to improve the signal, especially if the gain is turned up as well

But, without knowing any other variables, such as, did you try different positions in both the movement holder and directly onto the pick-up and clamp, then they can't be ruled out. You may find that the pick-up and clamp are brushing slightly on the barrel teeth, or the movement holder presses on the side of the balance cock to lift it so slightly to increase end-shake and thus squeeze a bit more amplitude out, because there was a slight bind to begin with.

I'm playing devil's advocate, here. But it's good to take a different tack on the problem

[nickelsilver]

Don't these have a gain adjustement? I put movements in movement holder on my Witschi all the time, but every now and then have to adjust the gain.

[VWatchie]

16 minutes ago, nickelsilver said:

Don't these have a gain adjustement? I put movements in movement holder on my Witschi all the time, but every now and then have to adjust the gain.

Oh yes, they do, but I never tamper with it. Not that it is difficult (it's just pressing an up and a down button) but as I've been unable to fully understand its purpose I haven never changed it. The manual (Chinese to English via Google translate) didn't make much sense. Take a look at the last picture in my first post. The machines automatically switches between showing BEAT and GAIN every 10 seconds or so. So, move the green "progress bar" to the right to increase sensitivity and to the left to decrease sensitivity? And, what should I look for? Changes in amplitude I guess, but when do I know I have the "correct gain"?

[spectre6000]

The point of gain is to increase/decrease the amplification of the signal. If the suspicion is that it's not picking up part of the waveform because it's muffled by the movement holder, turning up the gain may bring it back into a readable range. The flip side, is if you're in a loud room or something and you're getting interference with the reading, you can turn the gain down to hopefully reduce that interference with your reading.

[VWatchie]

1 hour ago, Jon said:

I'm playing devil's advocate, here. But it's good to take a different tack on the problem

Much appreciated and your points could very well be significant. I'll have a go using different positions once a get a chance to.

[VWatchie]

1 hour ago, spectre6000 said:

muffled by the movement holder

Or perhaps amplified by the movement holder!? Anyway, I hope to be recording the slow-motion video tomorrow and publish it here.

Perhaps I should mention that my Omega 268 is a rather loud sounding movement. The ticks can be heard within 25 cm of the movement in a quiet room.

Edited March 24, 2021 by VWatchie

[Endeavor]

26 minutes ago, VWatchie said:

Perhaps I should mention that my Omega 268 is a rather loud sounding movement. The ticks can be heard within 25 cm of the movement in a quiet room.

As if it is not complicated enough, another variable in the mix ! How good / sensitive are you ears?

[praezis]

Yes, but the release noise can still be silent (remember one of several in a tic).

Sometimes so silent that it is hard to separate it from random noise. In that case I don't expect much help from more amplification, as both are amplified.

Lets see what the video can tell

Frank