The point was simply that test records are fantastically horrible devices for measurements. The DIN record was a gross illustration of the variability, however differences are easy to find within the same track, even seconds apart. Not that there's any such thing as finite repeatability with these methods.
As I'm boxing up my 10R for awhile I decided to do some measurements before doing so. These were done in my basement with a 200lb maple top table with heavy duty industrial legs. The table is in the corner of the foundation, so three legs rest on foundation footers and only one on the slab. Obvious things like turning off the heating system were done to prevent as much vibration as possible. Not the most ideal environment, but the best I can do ATM.
I'm only showing torque 1 vs 5 here though I took 5 measurements of each of the 5 torque settings. I may process those later, but I doubt it.
Attached:
1) Video test record centering. Not perfect but good enough for a rush job.
2) Scatter plot of the MI data. Torque 5 (T5) is the left set and the deviating colors on each series are the mean.
3) Spectrum of T5 vs. T1. This is only one sample of each, but the rest weren't remarkably different.
4) Polar plots of T1 and T5. These are from the same recordings as the spectrum. Also very consistent between settings.
The audio samples I used are indexed - they all start at the same point on the record and are the same duration for measurement consistency. You'll notice this on the polar plots.
The MI data is unweighted as I wanted a cleaner look at the numbers. RMS drift and RMS wow favor T5 and are very consistent. RMS W&F is close while the rest favor T1 though there is significant overlap.
On the demodulated spectrum T5 measured better at 0.55Hz every time. Not sure why Noel's measurement were so different there, but as mentioned his results didn't make sense. The most notable difference between T5 and T1 across the board were at 1.65Hz and 3.89Hz, favoring T1.
What stood out to me was the polar plots - the errors in the test record are, for lack of a better description, smoothed out with the T1 setting. Is the flutter measurement slightly better because the motor is being a bit lazy reacting to dynamic changes? This aligns with the better drift and wow figures for T5.
A next step would be to re-do these measurements and analysis while playing a typical modulated groove (music) with a second arm. I don't think a conclusion can be drawn on the subject without that data. As what I see thus far is quite far below audibility, that's a torch I'll leave for someone else to pick up.
In short: inconclusive. Though I know which torque setting I'd use.
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Centering video: SP-10R W&F Test Record Centering - YouTube
As I'm boxing up my 10R for awhile I decided to do some measurements before doing so. These were done in my basement with a 200lb maple top table with heavy duty industrial legs. The table is in the corner of the foundation, so three legs rest on foundation footers and only one on the slab. Obvious things like turning off the heating system were done to prevent as much vibration as possible. Not the most ideal environment, but the best I can do ATM.
I'm only showing torque 1 vs 5 here though I took 5 measurements of each of the 5 torque settings. I may process those later, but I doubt it.
Attached:
1) Video test record centering. Not perfect but good enough for a rush job.
2) Scatter plot of the MI data. Torque 5 (T5) is the left set and the deviating colors on each series are the mean.
3) Spectrum of T5 vs. T1. This is only one sample of each, but the rest weren't remarkably different.
4) Polar plots of T1 and T5. These are from the same recordings as the spectrum. Also very consistent between settings.
The audio samples I used are indexed - they all start at the same point on the record and are the same duration for measurement consistency. You'll notice this on the polar plots.
The MI data is unweighted as I wanted a cleaner look at the numbers. RMS drift and RMS wow favor T5 and are very consistent. RMS W&F is close while the rest favor T1 though there is significant overlap.
On the demodulated spectrum T5 measured better at 0.55Hz every time. Not sure why Noel's measurement were so different there, but as mentioned his results didn't make sense. The most notable difference between T5 and T1 across the board were at 1.65Hz and 3.89Hz, favoring T1.
What stood out to me was the polar plots - the errors in the test record are, for lack of a better description, smoothed out with the T1 setting. Is the flutter measurement slightly better because the motor is being a bit lazy reacting to dynamic changes? This aligns with the better drift and wow figures for T5.
A next step would be to re-do these measurements and analysis while playing a typical modulated groove (music) with a second arm. I don't think a conclusion can be drawn on the subject without that data. As what I see thus far is quite far below audibility, that's a torch I'll leave for someone else to pick up.
In short: inconclusive. Though I know which torque setting I'd use.
-----------------------------------------------------------------------
Centering video: SP-10R W&F Test Record Centering - YouTube
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As the SP-10MKII/2A, MK3, and R chassis are essentially the same size one can just image search to find pictures of the combo. I found this one: SP10 advice - 2 Channel - HiFi WigWam
Due to the chassis shape a 9" arm has to be mounted quite far forward. It'll work fine, but the aesthetics and use-ability are a bit out of the norm.
Due to the chassis shape a 9" arm has to be mounted quite far forward. It'll work fine, but the aesthetics and use-ability are a bit out of the norm.
Hello,
Just reading through this thread -- I am impressed with the thought and work you have all put into the content here.
Im up and running at SP10r with an older Moerch DP-6 tone arm. The arm is currently hanging off the side of the unit, bolted with a plywood arm board. I'll be building a first test plinth soon. ...hoping to get a few pointers and tips along the way.
Just reading through this thread -- I am impressed with the thought and work you have all put into the content here.
Im up and running at SP10r with an older Moerch DP-6 tone arm. The arm is currently hanging off the side of the unit, bolted with a plywood arm board. I'll be building a first test plinth soon. ...hoping to get a few pointers and tips along the way.