Fun with vinyl measurements

[JP]

Have always found the phone app W&F ’measurements’ to be quite poor.

 

[watchnerd]

Have always found the phone app W&F ’measurements’ to be quite poor.

I‘ve certainly been suspicious as the consistency is not great from run to run and even minor changes in phone placement seem to have an impact.

I’m looking forward to the forthcoming speed test feature for the Puffin.

 

[Balle Clorin]

I put th Phone like this

I get consistent results with the app. At present Average speed varies by 0.01-rpms 10 runs in a row and peak wf between 0.09 and 0.12%In the absolute deviation from test record and stroboscope is 0.20% , so the app runs a bit too slow. Place the phone on top of a clamp or pick and make sure it is centered. A slight invisible level difference between pulley and platter has a major impact on stability. I adjusted by trial and error - bubble level not accurate enough. I get best results on Gyro with the chassis barely touching the felt washers :Ai the hint it dampens the bounce in a positive way
Having the phone in the side of the spindle , not centered gives invalid , too high wf numbers.

 

[watchnerd]

I put th Phone like this

I get consistent results with the app. At present Average speed varies by 0.01-rpms 10 runs in a row and peak wf between 0.09 and 0.12%In the absolute deviation from test record and stroboscope is 0.20% , so the app runs a bit too slow. Place the phone on top of a clamp or pick and make sure it is centered. A slight invisible level difference between pulley and platter has a major impact on stability. I adjusted by trial and error - bubble level not accurate enough. I get best results on Gyro with the chassis barely touching the felt washers :Ai the hint it dampens the bounce in a positive way
Having the phone in the side of the spindle , not centered gives invalid , too high wf numbers.

You do it with a record playing?

How much is the stylus drag vs no record?

 

[Balle Clorin]

I have done it with and without record playing, I do not see any difference . The impact of Stylus drag seem to be a myth..:
Here is 0.09% with phone centered on top of clamp .
Notice the even variation twice per revolution... this is what I get when the phone is centered and the pulley and chassis optimal leveled

If the chassis is not optimally level, I get uneven peaks .

With the phone not centered, but placed on the side of the spindle, in this case to the side of the clamp/label . the recorder wow goes up and peaks become uneven..

These uneven peaks happen also when chassis in not optimally leveled even if phone is in center. I adjust feet on the Gyro to get even peak,s then I always get the lowest wf%. But I now seem unable to get down to the 0.05% I had before remounting the player after oil and belt change.( stupid me)

Also having some talcum on the belt gave much better stability.

Too fast today I see, +0.2% or 33.4 rpm on app is 33 1/3 on stroboscope/ test record. I can get 0.1RPM varaiation form day to day depending of room temp or other unknown factors

 

[JP]

Here's W&F measurements from the motor FG and from a test record. On an app this 'table measures ~.11% at best. Fairly random results each time between .11% lowest and .15% highest. With a record and a "meter" you can watch the ballistics and kind of eyeball out record eccentricity. Needless to say records and apps are my last resort for these types of measurements.

Last is polar plot of the test record measurement.

 

[Thomas_A]

I think as JPJ says, these apps have some limitations. They give a bit different results depending on placement and the app itself.

 

[Balle Clorin]

Here's W&F measurements from the motor FG and from a test record. On an app this 'table measures ~.11% at best. Fairly random results each time between .11% lowest and .15% highest. With a record and a "meter" you can watch the ballistics and kind of eyeball out record eccentricity. Needless to say records and apps are my last resort for these types of measurements.

Last is polar plot of the test record measurement.

View attachment 112930

View attachment 112931

View attachment 112933

Motor FG?? ?
How do you place the Phone? On center or on side of spindle

 

[JP]

Frequency generator. Phone centered.

 

[levimax]

Plastic fantastic Technics SL-DD22 with "RPM Speed and Wow" App

33 1/3 RPM -0.08

Speed Min 33.29 rpm
Speed Max 33.32 rpm

Wow'2sigma +/-0.03%

 

[dennis h]

Rule #1 in testing devices :
Test the device as it is used
I have never played a record with a phone sitting on it
And never will
I will test a record player with an accelerometer on it for vibration analysis and other things, but you would need somewhere north of 50 of them to equal the mass of your cell phone

 

[Balle Clorin]

Not perfect but , Not much of a problem . A phone does not weigh much compared to the record clamps many use. For an unsuspended deck a phone on the center will not matter much. For a suspended deck it can matter as it may change elevation between motor pulley and sub platter. A phone weighs 0.2 kilogram and a platter 2-20 kg and has a very marginal effect on the inertia and bearing.
Of course a test record and WFGUI and Auduacity with wow and flutter addin can be a better way . But the problem is to find a quality test record , most are eccentric with far more wow than a Technics.
I have compared all methods
Stroboscope
Testrecord )Bruel&Kjær and Clearaudio are the best og the 10 I have )with WFGUI
Testrecord with Audacity with add-in , Spectral Lab, Rightmark and other

The Strobe is good but does not give a number. And wow must be large to be seen
My Ihphone app is too fast +0.2% but the speed variations fit nicely with my best testrecord and demodulating the speed variations

I do not understand your absolute reluctance to use the phone. It gives agood indication of speed variation and the speed bias can be found by comparing with a strobe.
I understand if accurate speed is the only object a strobe is best. But the phone app helped me bring my peak speed variations from 0.3% to 0.1% and less.Confirmed by WFGUI.

Just try it. It is easy , fun if you get good result and maybe frustrating if you get bad. Just remember to set the absolute speed by stroboscope and you are OK.


Here is an overlay comparison of the Iphone app and test record done syncronized

 

[dennis h]

No worries you have measured more analog stuff than I have and I have a different philosophy on testing devices is all.
( my Autoranger showed up today so I am getting closer)
Thanks for the heads up on the Clearaudio test record, I was wondering if it was any good.
What have you used it for?

 

[Balle Clorin]

Clearaudio have at least two test records.
1. Trackability test record. Side One has tracks to test cartridge tracking at different levels. 50/50/70/80 um. Side Two has a 15 minutes 3150hz track for long Wow&flutter test. It also have a endless groove on the outer edge to help center the record for minimum wow.

2. TRS 1007 test track for cartridge frequency . Google it . Supposed to be a copy of the famous JVC TRS 1007 that Audio Technica use to test cartridges
I Think you need a special preamp, the pre-emphasis is not RIAA

https://www.technologyfactory.eu/en/clearaudio/accessories/g-10000142?page=2

 

[Balle Clorin]

Audio Technica OC9/ML/II and Clearaudio TRS1007 ( JCV clone) Though Parks Audio Puffin 500R-00 setting suited for constant velocity over 1k, and equalized 10dB/Decade to plot linearly ( RTA-to--spectrum transformation for REW spectrum plot to be linear)

Many steps to get there since test record needs special equalization different from RIAA.
1. Parks audio Puffing EQ 500R-0.0 only bass equalization. Recorded digitally to CoolEdit Pro in PC through USB soundcard.
2. Plotting spectrum and RTA gives different slope on frequency. the transformation is 10dB/decade. ( A spectrum of pink noise slopes 3db/octave=10db/decade as spectrum , but plot as horisontal with RTA. Transformation is by software filter in Audacity
3. Import transformed file in REW and plot with some smoothing

If anyone have an easier way please let me know!!




Comparing EQ 500R-00 and no EQ=Line in with record stated response ( transformed to RTA response)

.

 

[watchnerd]

Audio Technica OC9/ML/II and Clearaudio TRS1007 ( JCV clone) Though Parks Audio Puffin 500R-00 setting suited for constant velocity over 1k, and equalized 10D/Decade to plot linearly ( RTA-to--spectrum transformation for REW spectrum plot to be linear)
View attachment 115244


Many steps to get there since test record needs special equalization different from RIAA.
1. Parks audio Puffing EQ 500R-0.0 only bass equalization. Recorded digitally to CoolEdit Pro in PC through USB soundcard.
2. Plotting spectrum and RTA gives different slope on frequency. the transformation is 10dB/decade. ( A spectrum of pink noise slopes 3db/octave=10db/decade as spectrum , but plot as horisontal with RTA. Transformation is by software filter in Audacity
3. Import transformed file in REW and plot with some smoothing
View attachment 115245


If anyone have an easier way please let me know!!

.

I've used the Puffin in a simpler way by:

1. Turn off RIAA EQ in the Puffin
2. Rip to Audacity
3. Plot using the Python cartridge graphing script

 

[Balle Clorin]

How do I do point 3?

 

[watchnerd]

How do I do point 3?

Use the Python script posted in the MM vs MI vs MC thread.

 

[Balle Clorin]

Sorry I need Python for Dummies, it is all Greek to me... I once programmed in Fortran and Pascal, but this is way over my head
'

https://www.audiosciencereview.com/forum/index.php?threads/mm-vs-mi-vs-mc.18636/post-669665

What do I do with this, The Python 3.8 manual seem to me as made by Marsians
I continue my education in the MM-MI MC thread

 

[watchnerd]

Sorry I need Python for Dummies, it is all Greek to me... I once programmed in Fortran and Pascal, but this is way over my head
'View attachment 115391

https://www.audiosciencereview.com/forum/index.php?threads/mm-vs-mi-vs-mc.18636/post-669665

What do I do with this, The Python 3.8 manual seem to me as made by Marsians
I continue my education in the MM-MI MC thread

I run it from a bash shell.

e.g.

david@Shingen cart % python cartridge.py

But, yes, better to talk about it in the other thread where the authors hang out.