Halcro -
I would also remind you that in your earlier testing you indicated that you got different results if you rotated the record a quarter turn.
I would also expect for example differences in the shape of the traces according to motor type - AC motors tend to self correct sinusoidally, whereas DC motors tend to correct trapezoidally.
An important point is that we can only do true comparisons where the testing instruments, protocols, and environment are constant. In other words comparing your results to Fremers is not scientifically valid. There will be differences in the test records, there are errors integral in the iPhone/computer apps that vary depending on model, and many other variables.
10-23-15: HalcroThat is not correct - point 2 in my post you refer to highlights that the Feickert test record can be prone to error - evidenced by the fact that the weighted averaging process is supposed to account for eccentricities in the record ( see Feickert for confirmation ).
..Dover still resorts to imagined 'monsters' from his antipodal 'sleep of reason' as witnessed by
4.The timeline only measures the arrival of a single point on the platter at the same place at each time. It does not measure what happens in between.
He strangely ignores the Feikert Frequency Response Charts posted which demonstrate a 'real-time' ANALOGUE print-out over a 30 second time interval....an interval comprising 16 revolutions of the platter....which disproves his (and your) theory of malevolent speed behaviour BETWEEN the Timeline recording interval.
10-23-15: HalcroIndeed, you have confirmed that the Feickert is not accurate enough to quantify the micro changes in speed between the test intervals.
As for your idea of testing the various arm/cartridge combinations on my TT-101...I don't believe the Feikert Speed App is accurate enough for this contest. In fact....if you conduct three 30 second test measurements with the identical table/arm/cartridge (without touching the set-up)...you will receive three sightly different results.
I would also remind you that in your earlier testing you indicated that you got different results if you rotated the record a quarter turn.
10-24-15: RichardkrebsIn Fremers testing thus far he highlights the vastly different shapes of the raw trace between the Caliburn and the Onedof even though they measure similarly, indicating differences in micro timing vs macro timing.
As for Dover's and my comments about what is happening "between" each pulse of the time line. I was hoping that this topic was in the 'agree to differ basket', but since it has been raised....you only need look at the traces you have just posted. Sharp spikes on the raw trace... this is a servo in action! Rapid acceleration/deceleration of the platter. Yet the platters average speed is 33 1/3. The smoothed ( green) trace filters these spikes, so it tells only part of the story.
I would also expect for example differences in the shape of the traces according to motor type - AC motors tend to self correct sinusoidally, whereas DC motors tend to correct trapezoidally.
An important point is that we can only do true comparisons where the testing instruments, protocols, and environment are constant. In other words comparing your results to Fremers is not scientifically valid. There will be differences in the test records, there are errors integral in the iPhone/computer apps that vary depending on model, and many other variables.