Quote:
Originally Posted by amanbra
Okay I now understand what you meant, another forum member helped explain that there are multiple sounds with in the tick that human ear hears which I think is what you mean here.
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I think the heart of your question comes down to this: a timegrapher can't "see", it can only "hear"... so how do you "hear" an angle
**? The bottom line is you don't. The timegrapher uses internal lookup tables to convert the timing between successive sounds into an angle. It does NOT directly measure this angle. By giving the timegrapher a single parameter - the lift angle - it can then scale/adjust its conversion of the timing to the amplitude angle. But if it doesn't know how many degrees come between sound A and sound B then it has no way to calculate the total degrees of sweep.
So let's use a basic example just making up numbers. If the timegrapher has measured the time between the two sounds to be Xms and you have told it that the angle moved between those two sounds is 50 degrees, it can now go and run some math and say ok, since the escapement moved from A to B, i.e. 50 degrees, in Xms, I know it is accelerating at Y rate, and therefore I estimate it will swing out to a max angle of Z degrees amplitude. But if you go back in and say "oh, just kidding, the angle between those two sounds is actually only 25 degrees" well now that completely changes its calculation. If I tell you that I ran 500m in 10 seconds you'd calculate I was going super fast, but if I say, oh wait, I only ran 5m in 10 seconds you'd calculate a totally different, and much slower, speed.
And what the timegrapher does is estimate, to continue the analogy, how far you'd get in 30 seconds even though it only has your timings for the 10 second part (between the two sounds it hears). So in the one case it says "he made it 500m in 10 seconds, and that's coming from a dead stop, so he'll probably make it 3000m in 30 seconds" (it is non-linear due to the accel/decel of the escapement). But in the second case, it says "oh, he only made it 5m in 10 seconds, so maybe he only gets 30m total in 30 seconds". Either way, it's a calculation based on heuristics, not a directly measured stat.
This angle (i.e. the distance in the running analogy) between the heard sounds is the lift angle and it is completely baked into the design of the movement. It's not something that can be adjusted, nor does it go up or down if the movement is healthy/sick. You either enter the correct number for your movement, or, you get worthless results out of the machine.
And finally, there is no direct correlation between amplitude and spd. In general we say that a movement is healthier if it has higher amplitude, but that doesn't mean its timing is correct in that state. When my Sub has normal amplitude it is regulated to around 0 spd. When the PR is very low and the amplitude has dropped nearly 100 degrees the spd is now like -25. But what if I went in and regulated it such that spd was 0 when the amplitude was super low? Now when the amplitude was good, i.e. much higher, the spd would be way off. In general, higher amplitude should provide more consistent timing (i.e. better isochronism) and then a simple regulation should have you in good shape. If the timing is inconsistent, you'll always be chasing your tail with regulation.
** The very high end, modern Witschi machines actually do have an optical sensor that allows them to literally see the escapement and thus directly measure the amplitude angle. But 99.9% of timegraphers on this planet do not have this capability.